Abstract:
A display device is provided. The display device includes a display panel comprising a display surface configured to display an image thereon, the display surface having an edge; a light source spaced apart from the display panel to form a space therebetween and configured to emit light to the display panel, wherein the display panel is configured to generate image on the display surface using the light from the light source; and a reflective surface arranged so as to reflect light emitted from the light source and to direct the reflected light to the edge.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application makes claims priority to and the benefit of Korean Patent Application No. 10-2006-0112214 filed on Nov. 14, 2006 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    The present invention relates to a display device. 
         [0004]    2. Description of the Related Technology 
         [0005]    The field emitter array (FEA) is known as an electron emission device. The FEA-type electron emission device typically includes an electron emission element, and cathode and gate electrodes to function as driving electrodes for controlling the electron emission of the electron emission device. The electron emission elements can be formed by a material having a relatively lower work function or a relatively large aspect ratio such as, for example, a carbon-based material including carbon nanotubes, graphite, and diamond-like carbon. The material is selected to effectively emit electrons when an electric field is formed around the electron emission elements under a vacuum atmosphere. 
         [0006]    The electron emission elements are typically arrayed on a substrate to constitute an electron emission device. The electron emission device may be combined with another substrate, on which a light emission unit having phosphor layers and an anode electrode may be formed to constitute a light emission unit. A display device is manufactured by combining a display panel with the light emission unit. 
       SUMMARY OF THE INVENTION 
       [0007]    According to one embodiment, a display device includes a display panel comprising a display surface configured to display an image thereon, the display surface having an edge; a light source spaced apart from the display panel to form a space therebetween and configured to emit light to the display panel, wherein the display panel is configured to generate image on the display surface using the light from the light source; and a reflective surface arranged so as to reflect light emitted from the light source and to direct the reflected light to the edge. 
         [0008]    According to another embodiment, a display device includes a surface light source configured to emit visible light; an array of pixels forming a display surface and arranged to receive visible light from the surface light source, wherein each pixel is configured to selectively pass visible light incident thereto such that the array as a whole can display an image on the display surface; a frame framing the display surface so as to define a viewing area of the display surface, wherein the frame comprises an edge defining an edge of the viewing area; and a mirror reflective with respect to visible light and extending generally parallel to the edge of the viewing area. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an exploded perspective view of a display device according to an embodiment. 
           [0010]      FIG. 2  is a cross-sectional view taken along line II-II of  FIG. 1 . 
           [0011]      FIG. 3  is a sectional view of a display device according to another embodiment. 
           [0012]      FIG. 4  is a perspective view of a fixing member of a display device according to another embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]    With reference to the accompanying drawings, embodiments will be described in order to enable those skilled in the art to be able to implement them. As those skilled in the art would realize, the described embodiments may be modified in various ways, all without departing from the spirit or scope of the present invention. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
         [0014]    It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present between them. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
         [0015]    It will be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, elements, layers, and/or sections, these elements, components, elements, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, element, layer, or section from another element, component, element, layer, or section. Thus, a “first” element, component, element, layer, or section discussed below could be termed a “second” element, component, element, layer, or section without departing from the teachings of the invention. 
         [0016]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including”, when used in this specification, are intended to specify the presence of stated features, elements, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, integers, steps, operations, elements, components, and/or groups thereof. 
         [0017]    Spatially relative terms, such as “beneath,” “below,” “lower.” “above,” “upper,” “over,” and the like may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that these 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. For example, if a device shown in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be considered oriented “above” the other elements or features. Thus, the term “below” can encompass an orientation of both above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly. 
         [0018]    Unless otherwise defined, all terms (including technical and scientific terms) used herein can have the same meaning as commonly understood by one with 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 present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0019]    Embodiments are described herein with reference to perspective views that are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations caused by, for example, various manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments should not be construed as limited to the particular shapes of elements illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. As an example, an element illustrated or described as flat may have rough and/or nonlinear features. Moreover, angles that are illustrated as sharp may be rounded. Thus, the elements illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of an element and are not intended to limit the scope of the present invention. 
         [0020]      FIG. 1  illustrates an exploded view of a display device  100  according to an embodiment. 
         [0021]    The display device  100  includes a display panel  70  and a light source unit  20 . The display device  100  may further include fixing members  60 ,  63 , and  66  for fixing and supporting the display panel  70  and the light source unit  20 . A diffuser plate  50  may be located between the display panel  79  and the light source unit  20  for diffusing the light emitted from the light source unit  20 , and supplying it to the display panel  70 . The diffuser plate  50  may be removed. 
         [0022]    A liquid crystal display panel may be used as the display panel  70 . The display panel  70  may include upper and lower substrates  701  and  703 . The upper and lower substrates  701  and  703  may be made of a glass material. Polarizers (not shown) may be attached on respective outer surfaces of the upper and lower substrates  701  and  703  to polarize the light. Liquid crystal may be injected between the upper and lower plates  701  and  703 . A color filter, a gate line, a data line, a thin film transistor (TFT) and the like may be formed at each display pixel between the upper and lower substrates  701  and  703 . The TFT may be turned on or off according to a driving signal that can be transmitted through the gate and data lines to vary an orientation angle of the liquid crystal, thereby displaying an image on the display panel  70 . 
         [0023]    In order to apply the driving signal to the gate and data lines of the display panel  70 , gate and data printed circuit boards  705  and  707  may be connected to the display panel  70  through driver integrated circuit packages (driver IC packages)  709 . A tape carrier package (TCP) or a chip on film (COF) may be used as the driver IC package  709 . The gate printed circuit board  705  can generate a gate driving signal and transmit the same to the gate line. The data printed circuit board  707  can generate a data driving signal and transmit the same to the data line. In order to minimize a non-display region of the display device  100 , the gate and data printed circuit boards  705  and  707  may be received in a side of the display device  100 . 
         [0024]    The light source unit  10  can supply light to the display panel  70 . As illustrated by the dotted lines in the light source unit of  FIG. 1 , the light source unit  10  may be driven by each light emission pixel, i.e., dimming drive. One light emission pixel of the light source unit  10  may correspond to two or more display pixels of the display panel  70 . Therefore, the light emission pixel can emit light having a brightness that is appropriate for the display pixel to the display pixel. As a result, the dynamic contrast ratio of an image displayed on the display panel  70  can be improved. 
         [0025]    An electron emission type light source unit may be used as the light source unit  10 . The electron emission type light source unit may be provided with a plurality of gate lines and a plurality of data lines. The gate and data lines may be connected to a printed circuit board  20  through the driver IC package  709 . The printed circuit board  20  can apply driving signals to the gate and data lines, thereby operating the light source unit  10 . 
         [0026]    In the illustrated embodiment, the fixing members  60 ,  63 , and  66  are first, second, and third fixing members, respectively. The first, second and third fixing members  60 ,  63  and  66  may be made of resin or metal. The first fixing member  60  may receive the diffuser plate  50 , the light source unit  10 , and the printed circuit board  20 . The second fixing member  63  may fix the diffuser plate  50  by covering the same. The display panel  70  may fixedly seat on the second fixing member  63 . The third fixing member  66  may cover the edges of the display panel  70  to fix the display panel  70  on the second fixing member  63 . In addition, the gate and data printed circuit boards  705  and  707  may be folded and fixed on an inner side of the third fixing member  66 . 
         [0027]    According to an embodiment, the inner sides of the second and third fixing members  63  and  66  include light reflective layers  601 . By supplying the light emitted from the light source unit  10  to the display panel  70  using the light reflective layers  601 , light loss can be minimized and light utilizing efficiency can be maximized. The light reflective layers  601  will now be described in more detail with reference to  FIG. 2  hereinafter. 
         [0028]      FIG. 2  is a schematic cross-sectional view taken along a line II-II of  FIG. 1  after the display device  100  of  FIG. 1  is assembled. In the circle inset of  FIG. 2 , an internal structure of the light source unit is illustrated as an enlarged view. A right region D with reference to a boundary line L corresponds with a display region, where the display panel  70  displays the image, and a light emission region, where the light source unit  10  emits the light. 
         [0029]    As illustrated in  FIG. 2 , the light source unit  10  may be spaced apart from the display panel  7  to define a space S. The space S can include the entire region where the diffuser plate  50  is positioned. By forming the space S, the light emitted from the light source unit  10  can be suitably diffused and then can be supplied to the display panel  70 , and thus the uniformity of the brightness of the light can be improved. Since the space S can be defined by a space surrounded by the first and second fixing members  60  and  63 , the inner sides of the first and second fixing members  60  and  63  can be adjacent to the space S. According to other embodiments, the space S may be defined by other methods rather than by the fixing members. 
         [0030]    The space S may include a side S 1 . Since the side S 1  includes the light reflective layer  601 , as indicated by the arrow of  FIG. 2  representing the light reflected, the side S 1  can reflect the light emitted from the light source unit  10  and direct the light toward the display panel  70 . Meanwhile, the inner sides of the first and second fixing members  60  and  63  can also respectively include reflective layers  601 . Therefore, the light loss can be minimized in the space S. Since the light loss can be minimized, there is no need to make the light emission region of the light source unit  10  large. As a result, as illustrated in the region D of  FIG. 2 , an area of the display region of the display panel  70  can be substantially identical to that of the light emission region of the light source unit  10 . 
         [0031]    In the case of a dimming drive type of light source unit, the light emitted from the light emission pixels located at a periphery region is partly lost due to its unique location. Especially in case of the dimming drive type of light source unit, since the light emission pixels are typically driven independently according to the dimming drive, it is difficult to compensate for the deterioration of the brightness from the adjacent light emission pixels. Therefore, the display quality of the image displayed at the periphery of the display panel is deteriorated since the brightness at the periphery is reduced. To prevent this, the light emission region of the light source unit is typically designed to be larger than that of the display region of the display panel in order to prevent the deterioration of the brightness at the periphery. 
         [0032]    However, in the present case, since the size of the light source unit can increase, the manufacturing cost can also increase and the receiving structure of the light source unit can become complicated during the manufacturing process. In addition, since there is typically a size difference between the display region of the display panel and the light emission region of the light emission unit, it is difficult to make the display pixels properly correspond to the light emission pixels of the light emission unit. 
         [0033]    According to an embodiment of the present invention, the use of light reflective layers  61  can prevent the reduction of the brightness at the periphery of the light source unit  10 . Therefore, as described above, the display region and the light emission region can be designed to have areas that are substantially identical to each other. As a result, since the light source unit  10  can be designed to be compact, the manufacturing cost can be reduced and accordingly, the light source unit  10  can be more conveniently received in the first fixing member  60 . 
         [0034]    The light reflective layer  601  may be formed by any material as long as it can reflect the light. For example, the light reflective layers  601  may be formed of aluminum. In order to maximize light reflectivity, the reflectivity of the light reflective layer  601 , i.e., a ratio of the amount of reflected light to the amount of light incident on the light reflective layer  601 , may be 80% or more. 
         [0035]    In addition, openings  603  can be formed in the first and second fixing members  60  and  63 . Therefore, the space S may communicate with an external side through the openings  63 . Since the space S is sealed, it may be heated to a high temperature by the thermal energy of the light emitted from the light source unit  10 . Therefore, the diffuser plate  50  may become deformed by the high temperature. Accordingly, the thermal deformation of the components can be prevented by circulating the air into the space S through the openings  603 . 
         [0036]    As illustrated in the enlarged circle inset of  FIG. 2 , the light source unit  10  may be the electron emission unit. Since the light source unit  10  in the illustrated embodiment has a plurality of electron emission elements for the respective light emission pixels, the dimming drive is possible. The internal structure and the operational principle of the light source unit  10  will now be described in detail. 
         [0037]    The light source unit  10  may include an electron emission device  1000 , an anode electrode  1101 , a phosphor layer  1103 , a spacer  1100 , etc. The spacer  1100  may be located between first and second substrates  101  and  103  facing each other to support them. 
         [0038]    The electron emission device  1000  may include cathode electrodes  1001 , electron emission elements  1003 , and gate electrodes  1005 . An insulation layer  1007  may be interposed between the cathode and gate electrodes  1001  and  1005  to prevent a short circuit from occurring between the cathode and gate electrodes. 
         [0039]    The cathode electrodes  1001  can be arranged on the first substrate  101  in a stripe pattern. The cathode electrodes  1001  can then be applied with a data driving voltage to function as data electrodes. The gate electrodes  1005  can be arranged in a stripe pattern extending in a direction (i.e., the x-axis) that crosses the cathode electrodes  1001 . The cathode and gate electrodes  1001  and  1005  may be made of a conductive material including an indium thin oxide (ITO) or another metal. 
         [0040]    The electron emission elements  1003  may be located at each crossed region of the cathode and gate electrodes  1001  and  1005 . The electron emission elements  1003  may be electrically connected to one of the cathode and gate electrodes  1001  and  1005 . For instance, the enlarged circle inset of  FIG. 2  shows an example of how the electron emission elements  1003  can be connected to the cathode electrodes  1001 . 
         [0041]    Openings may be formed in the insulation layer  1007  and the gate electrodes  1005  to allow the electrons emitted from the electron emission elements  1003  to pass through. By a voltage difference between voltages applied to the cathode and gate electrodes  1001  and  1005 , electrons e −  can then be emitted from the electron emission elements  1003 . 
         [0042]    The electron emission elements  1003  may be made of a material that emits electrons when an electric field is induced under a vacuum atmosphere, such as a carbon-based material or a nanometer-sized material. For example, the electron emission elements  1003  may include but are not limited to carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbon, C 60 , silicon nanowires, or a combination thereof. The electron emission device  1003  may be formed by various processes including but not limited to a screen-printing, chemical vapor deposition, sputtering, and the like. Alternatively, the electron emission elements  1003  may be formed in a Mo-base or Si-based pointed-tip structure. 
         [0043]    The phosphor layer  1103  and anode electrode  1101  may be provided on the second substrate  103 . Since a high voltage can be applied to the anode electrode  1101 , the electrons emitted from the electron emission elements  1003  can collide with the phosphor layer  1103  at a high speed. Therefore, light may be emitted from the phosphor layer  1103  to the external side through the second substrate  103 . 
         [0044]    Since the phosphor layer  1103  may be a white phosphor layer, white light can be emitted to the external side. Alternatively, the phosphor layer  1103  may be formed by red, green and blue phosphor layers emitting light of a variety of colors. 
         [0045]    As illustrated in the enlarged circle inset of  FIG. 2 , the phosphor layer and the anode electrode may be in an order such that the phosphor layer  1103  is formed over the second substrate  103  and the anode electrode  1101  is formed over the phosphor layer  1103 . Since the phosphor layer  1103  is adjacent to the second substrate  103  in the embodiment shown, the anode electrode  1101  would not interfere with the light emitted from the phosphor layer  1103 . Therefore, the anode electrode  1101  may be formed of non-transparent metal having a superior electric conductivity in the illustrated embodiment. 
         [0046]    Alternatively, the anode electrode and the phosphor layer may be formed in an order such that the anode electrode  1101  is formed over the second substrate  103  and the phosphor layer  1103  is formed over the anode electrode  1101 . In this case, since the light is emitted from the phosphor layer to the external side through the anode electrode and second substrate  103 , the anode electrode may be formed of a transparent material such as the ITO. 
         [0047]    The operation of the light source unit  10  will now be described with reference to the enlarged circle inset of  FIG. 2 . Predetermined driving voltages may be applied to the cathode and gate electrodes  1001  and  1005 . In this case, an electric field can be formed around the electron emission elements  1003  at a pixel where a voltage difference between the cathode and gate electrodes  1001  and  1005  is equal to or greater than a threshold value. As a result, electrons e −  can be emitted from the electron emission elements  1003 . The emitted electrons can collide with the phosphor layer  1003  of the corresponding pixel by being attracted by the high voltage applied to the anode electrode  1101 . Thus, the phosphor layer  1003  can be excited to emit the light to an external side through the second substrate  103 . 
         [0048]      FIG. 3  illustrates a schematic of a display device  200  according to another embodiment. Since the display device  200  illustrated in  FIG. 3  is similar to the display device  100  of  FIG. 2 , like reference numerals refer to like elements and the different features of the illustrated embodiment will be described. 
         [0049]    As illustrated in  FIG. 3 , an inner side of a first fixing member  61  that includes a light reflective layer  605  may be bulged toward the interior of a space S, or have a convex surface. In this case, the light emitted from the light source unit  10 , as indicated by the arrow in  FIG. 3 , can be more effectively reflected and directed toward the display panel  70 . In other words, a convex surface can reflect the light with a larger angle of incidence between the light emitted and the light reflected toward display panel  70 . As a result, the space between the active display and light emission regions from the first fixing member  60  can be minimized. In addition, a diffuser plate  50  or a printed circuit board  20  may be more easily fixed on the first fixing member  60 . 
         [0050]      FIG. 4  illustrates a first fixing member  60  in a display device according to another embodiment. Since the first fixing member  60  of  FIG. 4  is similar to those of  FIGS. 1 to 3 , the different features of the illustrated embodiment will be described. 
         [0051]    As illustrated in  FIG. 4 , a plurality of light reflective sections  607  may be formed on the inner side of the first fixing member  60 . The plurality of light reflective sections  607  are shown to be spaced apart from each other in a parallel manner, with non reflective sections  608  interposed between adjacent reflection sections  607 . In addition, the plurality of light reflective sections  607  may be arranged in a comb pattern as illustrated in  FIG. 4 , to minimize the loss of the light emitted from the light source unit. Therefore, the brightness of light supplied to the display panel, particularly, the brightness of the light at the periphery of the display panel, can be enhanced. Furthermore, the plurality of light reflective layers  607  can be spaced apart from each other to provide an air flow passage between the light reflective layers  607 . 
         [0052]    As described above, since the loss of light at the periphery of the display panel can be minimized by using a light reflective layer, the uniformity of the light can be improved and the overall light brightness can also be enhanced. 
         [0053]    Although exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.