Abstract:
A display device and a lighting device are provided. The display device includes a display element for outputting an image according to a provided image signal, a frame disposed on a rear surface of the display element, and a reflection layer formed on the frame and positioned between the display device and the frame, the reflection layer being a coating layer formed using a paint including at least one of silver and aluminum. When the backlighting device of the display device is configured, a reflection plate where deposition films and a reflection layer made of a metal component are deposited is not required and the reflection layer is formed on the frame by using a paint having at least one of silver and aluminum as its main components, thereby simplifying a manufacturing process, and contributing to reducing the thickness of the display device.

Description:
PRIORITY 
     This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Mar. 8, 2011 and assigned Serial No. 10-2011-0020612, the entire disclosure of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display device mounted on a portable terminal. More particularly, the present invention relates to a lighting device which facilitates reduction in the thickness of a backlighting device and a display device including the lighting device. 
     2. Description of the Related Art 
     Generally, the term “display device” refers to a device for presenting a screen with a provided image signal. The display device has been widely used in daily life for not only portable terminals, such as cellular phones, Portable Multimedia Players (PMPs), etc., but also electric appliances, such as navigation systems for vehicles, televisions (TVs), laundry machines, refrigerators, etc. 
     With the common use of a flat-panel display device such as a Liquid Crystal Display (LCD), the display device can now be mounted on a small-size device such as a portable terminal. Recently, a combination of a touch screen panel and a display device implements a virtual keypad on a screen in place of a physical keypad of the portable terminal. 
     Since the flat-panel display device cannot emit light itself, the display device visually presents a screen implemented through the display device with light provided from a separately installed light source. The flat-panel display device, at its early stages of development, displayed a simple character or symbol with combinations of black and white, such that lighting can be sufficiently provided by installing a point light source at a side of the display device. 
     Recently, however, as a television or a monitor for a computer, which uses a flat-panel display device, has been popularized and a multimedia service using a portable terminal is also rapidly increasing, there is a limitation in providing lighting for the flat-panel type display device with a point light source which has a large deviation in backlighting according to an installation position. As a result, effort has been exerted to provide lighting uniformly over the entire area of the display device by using a light guide plate or a sheet diffuser which converts a point light source into a surface light source. In addition, a reflection plate for efficient use of light generated from the light source is also mounted in the flat-panel type display device. 
       FIG. 1  is an exploded perspective view of a display device according to the related art. The display device  10  implements an image based on a provided image signal through a flat-panel display device  21 , and a backlighting device including a light source (not shown) provides lighting to allow a user to view the image implemented through the flat-panel display device  21 . The backlighting device includes a light guide plate  12 , a sheet diffuser  13 , and a prism sheet  14  which are disposed on a frame  11 , and the light source (not shown) is disposed on at least a side of the light guide plate  12 . A plurality of light sources may be installed in an actual product according to a size of the flat-panel display device  21  or the like. 
     The frame  11  may be provided to enclose a back surface and side surfaces of the flat-panel display device  21  while maintaining the shapes of the light guide plate  12 , the sheet diffuser  13 , and the prism sheet  14 . 
     The light guide plate  12  allows the light provided from the light source to be radiated over the entire area of the flat-panel display device  21 . In other words, a line light source radiated from the light source is converted into a surface light source through the light guide plate  12 . 
     The sheet diffuser  13  uniformly adjusts the light radiated from the light guide plate  12  toward the flat-panel display device  21  over the entire area of the flat-panel display device  21 . The light passing through the sheet diffuser  13  is refracted in various directions, thereby passing through the prism sheet  14 . 
     The prism sheet  14  converts side light, which passes through the sheet diffuser  13  and then goes in an inclined direction with respect to the flat-panel display device  21 , into front light. That is, the light passing through the prism sheet  14  enters the prism sheet  14  perpendicular to a surface of the flat-panel display device  21 . 
     The backlighting device described above is adhered to a back surface of the flat-panel display device  21  through a separate adhesive sheet (not shown). 
     The light radiated from the light guide plate  12  also goes to a back surface which does not face the flat-panel display device  21 , degrading lighting efficiency. Therefore, the backlighting device preferably includes a reflection plate  15  on the back surface of the light guide plate  12 . 
     The reflection plate  15  forms a reflection layer by depositing a metal component such as aluminum on a surface of a deposition film. In this case, since it is difficult to secure a sufficient refractive index only with a general metal component, deposition films on which reflection layers are formed are laminated and thermally compressed, after which thickness is reduced by a stretching process and a surface area is expanded, thus completing the reflection plate  15 . The completed reflection plate  15  is adhered to the back surface of the light guide plate  12  or the frame  11  through a separate adhesive tape  16 . 
     However, in the backlighting device of the related art, the reflection plate has disadvantages of a complex manufacturing process and a high possibility of a crack being generated in the reflection layer or the deposition film. Moreover, the reflection plate is manufactured by laminating the plurality of deposition films and then performing the stretching process, such that to dispose the reflection plate in an actual product, a separate cutting process and an adhering process using an adhesive tape are required. As a result, the assembly process of the reflection plate to the backlighting device as well as the manufacturing process of the reflection plate is cumbersome. Moreover, the thickness of the adhesive tape as well as the thickness of the reflection plate including the deposition films hinders reducing the thickness of the display device. 
     The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as Prior Art with regard to the present invention. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a display device including a backlighting device, which contributes to simplifying a manufacturing process. 
     Another aspect of the present invention is to provide a display device including a backlighting device, which contributes to reducing the thickness of the display device, and thereby reducing the thickness of a portable terminal in which the display device is mounted. 
     According to an aspect of the present invention, a display device is provided. The device includes a display element for outputting an image according to a provided image signal, a frame disposed on a rear surface of the display element, and a reflection layer formed on the frame and positioned between the display device and the frame, the reflection layer being a coating layer formed using a paint including at least one of silver and aluminum. 
     The frame may be formed of a plate using a metal material or an injection-molded product. 
     The display device may further include a bottom primer layer interposed between the frame and the reflection layer, and in this case, the bottom primer layer may be formed using a paint including at least one of acryl, urethane, silicon, epoxy, styrene, polyester, and high polymer polyester. 
     The display device may further include an ultraviolet (UV)-curing layer interposed between the bottom primer layer and the reflection layer. 
     The display device may further include a top coating layer formed on the reflection layer and positioned between the display element and the reflection layer. 
     The display device may further include an anti-tarnish layer coated on a surface of the reflection layer. 
     The display device may further include a silicon particle layer formed on the reflection layer and positioned between the display element and the reflection layer. 
     The display device may further include a bottom primer layer interposed between the frame and the reflection layer, an ultraviolet (UV)-curing layer interposed between the bottom primer layer and the reflection layer, a top coating layer formed on the reflection layer and positioned between the display element and the reflection layer, and an anti-tarnish layer coated on a surface of the reflection layer, in which at least one of the bottom primer layer, the UV-curing layer, the top coating layer, and the anti-tarnish layer may be formed using a paint to which at least one of a pigment, a dye, and a quencher are added. 
     Meanwhile, it can be easily understood by those of ordinary skill in the art that the reflection layer may be applicable to not only the display device, but also a lighting device used in daily life, for example, indoor lighting, a street lamp, a vehicle&#39;s head lamp, etc. 
     When the backlighting device of the display device is configured, a conventional reflection plate where deposition films and a reflection layer made of a metal component are deposited is not required and a reflection layer may be formed on a frame by using a paint having at least one of silver and aluminum as its main components, thereby simplifying a manufacturing process. In other words, it is unnecessary to deposit the metal component onto the deposition films to form the reflection layer or to deposit and stretch the deposition films where the reflection layer is formed, thus simplifying the manufacturing process. 
     Furthermore, the reflection layer may be directly formed on the frame disposed on the rear surface of the display device, thereby removing a need for cutting or adhesion of the reflection plate and thus contributing to reduction of the thickness of the display device, and thereby contributing to reduction of the thickness of a device having the display device mounted thereon, such as a portable terminal, due to the deposition films or an adhesive tape. 
     In addition, the reflection layer whose manufacturing process is simplified and whose thickness is easy to reduce can be applied to indoor lighting, a street lamp, a vehicle&#39;s head lamp, and so forth, thereby reducing the manufacturing cost of a device or equipment for which lighting is used. 
     Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of an exemplary embodiment of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective view of a display device according to the related art; and 
         FIG. 2  is a cross-sectional view of a display device according to an exemplary embodiment of the present invention. 
     
    
    
     Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiment of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions will be omitted for clarity and conciseness. 
     The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
     It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
       FIG. 2  is a cross-sectional view of a display device according to an exemplary embodiment of the present invention. According to exemplary embodiments of the present invention, the display device shown in  FIG. 1  may include additional and/or different components, or omit any number of the components shown in  FIG. 1 . Similarly, the functionality of two or more components may be integrated into a single component. 
     Referring to  FIG. 2 , a display device  100  according to an exemplary embodiment of the present invention includes a backlighting device in which a reflection layer  102  may be formed on a frame  101  disposed on a back surface of a display element  105 . The backlighting device may include a light guide plate, a sheet diffuser, a prism sheet, and so forth, but such a configuration can be easily understood by those of ordinary skill in the art and thus will not be described in detail herein. 
     The display element  105 , may be implemented with a flat-panel display element, and may be manufactured with various elements such as a Liquid Crystal Display (LCD) element, a Thin Film Transistor (TFT) LCD element, an Organic Light Emitting Diode (OLED) element, etc. Since the display element  105  generally cannot emit light by itself or cannot generate enough light to clearly implement a screen color, the display device  100  includes the separate backlighting device. 
     The backlighting device includes the frame  101  provided on the back surface of the display device  105  to enclose at least the back surface of the display device  105 , and the reflection layer  102  formed on a surface of the frame  101 . 
     The frame  101  provides a structure, although not shown, for installing a light source or a light guide plate of the backlighting device. The frame  101  may be coupled to the display element  105  to protect the display element  105 . The frame  101  may be manufactured by processing a plate using a metal material or manufactured with an injection-molded product. In other words, the frame  101  may be manufactured with a plate using a metal material such as iron, aluminum, magnesium, or the like, or with an injection-molded product using a synthetic resin material such as polycarbonate resin, ABS resin, natural rubber, or the like. 
     The reflection layer  102  includes a coating layer formed by coating a paint onto a surface of the frame  101 . The paint for the reflection layer  102  includes silver and aluminum as its main components, such that the surface of the frame  101  may be coated by spraying the paint onto the surface of the frame  101 , and the paint may be cured by thermal curing, thus completing the reflection layer  102 . The reflection layer  102  may be formed to have a thickness of at least 20 μm, thus securing a refractive index equal to or higher than that of a reflection plate of the related art. When the refection layer  102  is formed to have a thickness of 60-120 μm, its refractive index may be further improved and its durability may be improved. 
     Table 1 shows a comparison between a refractive index of a reflection plate of the related art having deposition films and a refractive index of a reflection layer according to an exemplary embodiment of the present invention. As can be seen in Table 1, the refractive index of the reflection layer according to the present exemplary embodiment of present invention may be equal to that of the reflection plate of the related art in a visible light spectrum. 
     
       
         
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
             
             
               
                 Visible Light Wavelength 
                 400 mm 
                 500 mm 
                 600 mm 
                 700 mm 
               
               
                 Reflection Plate Having 
                 89.4% 
                 89.4% 
                 96.6% 
                 96.5% 
               
               
                 Deposition Films 
                   
                   
                   
                   
               
               
                 Reflection Layer 
                 82.5% 
                 96.0% 
                 96.5% 
                 97.4% 
               
               
                   
               
             
          
         
       
     
     The frame  101  may be further formed with a bottom coating layer, a top coating layer  147 , an anti-tarnish layer  141 , a silicon particle layer  145 , and so forth to facilitate coating of the paint for the reflection layer  102  or to protect the reflection layer  102 . 
     The bottom coating layer may include a bottom primer layer  131  and an ultraviolet (UV)-curing layer  135 . The bottom primer layer  131  may be formed between the reflection layer  102  and the frame  101 , more specifically, on the surface of the frame  101 , and the UV-curing layer  135  may be formed on a surface of the bottom primer layer  131  to be positioned between the bottom primer layer  131  and the reflection layer  102 . 
     A surface treatment process for reinforcing affinity of the frame  101  with respect to the paint for the reflection layer  102  may be used to form the bottom primer layer  131  and the UV-curing layer  135 . The bottom primer layer  131  and the UV-curing layer  135  are formed by coating a paint including at least one of acryl, urethane, silicon, epoxy, styrene, polyester, and high polymer polyester at least once and are completed by thermally curing or UV-curing the coated paint. 
     The top coating layer  147  may be intended to protect the reflection layer  102 , and may be formed by coating a paint including at least one of acryl, urethane, silicon, epoxy, styrene, polyester, and high polymer polyester at least once and may be completed by thermally curing the coated paint. The top coating layer  147  may be formed on the reflection layer  102 , such that it may be positioned between the reflection layer  102  and the display element  105 . 
     The anti-tarnish layer  141  may prevent discoloration of the reflection layer  102  by preventing contamination or oxidation of silver (Ag) and aluminum (Al) which are the main components of the reflection layer  102 . To this end, the anti-tarnish layer  141  may be formed on the surface of the reflection layer  102 . The anti-tarnish layer  141  may be positioned between the reflection layer  102  and the top coating layer  147 . 
     The silicon particle layer  145  may be formed on the surface of the reflection layer  102  or the surface of the anti-tarnish layer  141  by applying or depositing a paint having silicon dioxide or silicon carbide as its main component. The silicon particle layer  145  suppresses damage of the reflection layer  102  such as a scratch on the surface of the reflection layer  102  and suppresses contamination of the surface of the reflection layer  102  due to a foreign substance or a worker&#39;s finger print. Moreover, the silicon particle layer  145  can be washed by water even when being contaminated by a foreign substance or a worker&#39;s finger print, such that the contamination substance can be easily removed therefrom. Although the silicon particle layer  145  may be formed on the surface of the reflection layer  102  or the surface of the anti-tarnish layer  141  in the present exemplary embodiment of the present invention, it may be formed on the surface of the top coating layer  147 . 
     When the bottom coating layer/the top coating layer  147  or the anti-tarnish layer  141  are formed, a pigment, a dye, a quencher, etc. may be added to the paint to minimize color distortion during reflection, refraction, and penetration of light emitted from a light source. Such addition may be intended to prevent a lighting color from distorting a color implemented by the display element  105 . 
     As mentioned previously, the backlighting device of the display device  100  may include a light guide plate and a sheet diffuser to convert a point light source into a surface light source and uniformly distribute light over the entire area of the display element  105 . 
     The thickness of the display device  100  structured as described above may be reduced by a minimum of 0.14 mm when compared to a display device including a reflection plate manufactured by depositing/stretching deposition films. 
     While the present invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. 
     For example, in a lighting device in which a reflector is installed behind a light source, such as indoor lighting using a fluorescent lamp or a Light Emitting Diode (LED), outdoor lighting such as a street lamp around a footpath or flood lighting around a road, or vehicle lighting such as a vehicle&#39;s headlamp, the reflection layer  102  may be formed. In this case, a frame positioned behind the light source may be manufactured with an injection-molded product or a metal material, and according to the manufacturing material, top/bottom coating layers, an anti-tarnish layer, a silicon particle layer, etc. may be formed to improve the durability of the reflection layer formed on the frame.