Abstract:
A display module includes: a main liquid crystal panel having a plurality of pixel regions formed on a surface thereof so as to display visual information; a barrier panel spaced a predetermined gap from the surface in the thickness direction so as to cover the surface of the main liquid crystal panel; and a refractive portion including at least one glass substrate so as to fill the gap. The freedom of design may be increased since the display module can maintain a prescribed thickness, and the portability may be improved by increasing rigidity.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2011-0049183, filed on May 24, 2011, the contents of which is incorporated by reference herein in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present disclosure relates to a mobile terminal including a display module for reproducing second-dimensional and three-dimensional images. 
         [0004]    2. Background of the Invention 
         [0005]    Terminals may be divided into mobile/portable terminals and stationary terminals according to their mobility. Also, the portable terminals may be categorized into a handheld terminal and a vehicle mount terminal according to whether it is directly portable by a user. 
         [0006]    As it becomes multifunctional, the terminal can be allowed to capture still images or moving images, play music or video files, play games, receive broadcast and the like, so as to be implemented as an integrated multimedia player. 
         [0007]    Recently, interest in stereoscopic image displays is growing, and a variety of products for implementing them are being released. 
         [0008]    Stereoscopic images may be roughly divided into spatial three-dimensional images using holography and stereographs using the difference in angle between a left image and a right image that the eyes are pointing. In one of the method for implementing stereography, a parallax barrier may be used to realize 3D. The parallax barrier method uses the principle that a parallax is generated between the eyes of a viewer by placing a filter with vertical slits in front of a display apparatus. 
         [0009]    However, in order to deliver XGA-level resolution on a display panel for both 2D and 3D with a screen size of 8.9 inches or greater, the rear distance from a color filter to a barrier needs to be equal to or greater than a predetermined value or more, which has been difficult to perform by a conventional method. 
       SUMMARY OF THE INVENTION 
       [0010]    Therefore, an aspect of the detailed description is to provide a display module in which the rear distance from color filters to barriers is equal to or greater than a prescribed distance. 
         [0011]    Another aspect of the detailed description is to provide a display module including a refractive portion with a prescribed refractive index or more which is laminated so that the rear distance is maintained. 
         [0012]    To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, a display module according to an embodiment of the present invention includes: a main liquid crystal panel having a plurality of pixel regions formed on a surface thereof so as to display visual information; a barrier panel spaced a predetermined gap from the surface in the thickness direction so as to cover the surface of the main liquid crystal panel; and a refractive portion including at least one glass substrate so as to fill the gap, wherein the barrier panel includes barriers that are disposed to cover at least part of color filters forming the pixel regions and are disposed to be spaced apart from each other to define slits at prescribed intervals, and the glass substrate contains predetermined percentages by weight of Nb 2 O 5 , BaO, and TiO 2 . 
         [0013]    In an embodiment related to the present invention, the refractive portion may further include at least one polarization layer, and the polarization layer may include an intermediate layer of an inorganic material. 
         [0014]    In an embodiment related to the present invention, the inorganic material may be formed by a material selected from the group consisting of SiO, SiO 2 , Al 2 O 3 , ZrO 2 , TiO 2 , GeO 2 , and mixtures and combinations thereof. 
         [0015]    In an embodiment related to the present invention, the barrier panel includes barriers that are disposed to cover at least part of color filters forming the pixel regions and spaced apart from each other to define slits at preset intervals. 
         [0016]    In an embodiment related to the present invention, the glass substrate may have a predetermined refractive index (n), and the refractive index (n) may be 1.8≦n≦2.3. 
         [0017]    In an embodiment related to the present invention, the refractive portion is disposed to be spaced apart at prescribed distances (d) in the thickness direction extending from the color filters to the barriers, and the distances are 0.55 mm≦n≦0.75 mm. 
         [0018]    In an embodiment related to the present invention, the refractive portion may further include at least one adhesion layer, and the adhesion layer may be formed of an organic or inorganic adhesion layer containing glass fibers. 
         [0019]    To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, a mobile terminal according to an embodiment of the present invention includes: a terminal body; and a display module incorporated in the terminal body and displaying image information, the display module including: a main liquid crystal panel having a plurality of pixel regions formed on a surface thereof so as to display visual information; a barrier panel spaced a predetermined gap from the surface in the thickness direction so as to cover the surface of the main liquid crystal panel; and a refractive portion including at least one glass substrate so as to fill the gap, wherein the barrier panel includes barriers that are disposed to cover at least part of color filters forming the pixel regions and are disposed to be spaced apart from each other to define slits at prescribed intervals, and the glass substrate contains predetermined percentages by weight of Nb 2 O 5 , BaO, and TiO 2 . 
         [0020]    To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, a mobile terminal according to an embodiment of the present invention includes: a terminal body; a main liquid crystal panel incorporated in the terminal body, and having a plurality of color filters spaced apart from each other and alternately disposed in a first direction to define a pixel; a barrier panel including slits for transmitting light emitted from the display panel and barriers arranged in the first direction so as to realize a 3D image; and a refractive portion disposed to space the main liquid crystal panel and the barrier panel apart from each other, wherein the refractive portion includes a plurality of layers, and the refractive index (n) of at least one of the layers is 1.8≦n≦2.3. 
         [0021]    The thus-configured display module related to at least one of the embodiments of the present invention can offer a resolution increase because of its high refractive index. 
         [0022]    According to the present invention, the freedom of design may be increased since the display module can maintain a prescribed thickness, and the portability may be improved by increasing rigidity. 
         [0023]    Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the invention. 
           [0025]      FIG. 1  is a perspective view of a mobile terminal related to an embodiment of the present invention; 
           [0026]      FIG. 2  is a rear perspective view of a mobile terminal related to an embodiment of the present invention; 
           [0027]      FIG. 3  is an exploded perspective view of the mobile terminal  100  of  FIG. 1 ; 
           [0028]      FIG. 4  is a conceptual diagram of a stereoscopic image display method related to an embodiment of the present invention; 
           [0029]      FIGS. 5A and 5B  are conceptual diagrams of 2D and 3D operation modes of a display module related to an embodiment of the present invention; 
           [0030]      FIG. 6  is a conceptual diagram illustrating a lamination structure of a barrier panel, refractive portion, and main liquid crystal panel of the display module related to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    Hereinafter, a display module related to the present invention and a mobile terminal including the same will be described in more detail with reference to the drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated. Singular expressions include plural expressions which do not have any obviously different meaning in view of a context. 
         [0032]    The suffixes “module” and “unit or portion” for components used in the following description merely provided only for facilitation of preparing this specification, and thus they are not granted a specific meaning or function. 
         [0033]    The mobile terminal described in the specification can include a cellular phone, a smart phone, a laptop computer, a digital broadcasting terminal, personal digital assistants (PDA), a portable multimedia player (PMP), a navigation system and so on. However, those skilled in the art will easily understand that configurations according to embodiments of the present disclosure can also be applied to stationary terminals such as digital TV and desktop computers except a case where the configurations can be applied to only mobile terminals. 
         [0034]      FIG. 1  is a perspective view of a mobile terminal  100  related to an embodiment of the present invention when viewed from the front. 
         [0035]    A case (a casing, a housing, a cover, etc.) forming the exterior of the body of the terminal is formed by a front case  111  and a rear case  121 . Electronic components are disposed in a space formed by the front case  111  and the rear case  121 . At least one intermediate case may be additionally disposed between the front case  111  and the rear case  112 . The cases may be formed of a synthetic resin in a manner of injection, or formed of a metallic material such as stainless steel (STS) or titanium (Ti). 
         [0036]    A display  113 , a first audio output unit  114 , a first image input unit  115 , a first manipulation portion  116 , and an audio input unit  117  may be disposed at the front case  111 . 
         [0037]    The display  113  includes a display module  200  (see  FIG. 3 ) such as a Liquid Crystal Display (LCD) module, an Organic Light Emitting Diodes (OLED) module, etc., to visually represent information. 
         [0038]    The display  113  may further include a touch screen so that the user can input information by touch. 
         [0039]    The first audio output unit  114  may be implemented as a receiver or a speaker. 
         [0040]    The first image input unit  115  may be implemented as a camera module for shooting an image or moving picture for the user. The first manipulation portion  116  is configured to receive a command for controlling an operation of the mobile terminal  100  related to an embodiment of the present invention. 
         [0041]    The first audio input unit  125  may be implemented, for example, as a microphone to receive user&#39;s voice or other sounds. 
         [0042]    The rear case  121  mounted on the rear surface of the mobile terminal  100  may be provided with a second manipulation portion  123 , an interface  124 , a power supply unit  125 , etc. 
         [0043]    The second manipulation portion  123  may be disposed on a side surface of the rear case  121 . 
         [0044]    The first and second manipulation portions  116  and  123  may be broadly referred to as a manipulation portion, which can be adapted or implemented in any manner, such as a tactile manner that the user can touch for manipulation. 
         [0045]    For example, the manipulation portion may be implemented as a dome switch, the touch screen or a touch pad by which the user can input commands or information by push or touch thereof. Alternatively, the manipulation portion may be implemented, for example, as a wheel, a jog, or a joystick. 
         [0046]    Functionally, the first manipulation portion  116  is configured to input commands such as start, end, or the like, and the second manipulation portion  123  can work as a hot key which performs a specific function, such as activating the first image input unit  115 , as well as the scroll function. 
         [0047]    If the first and second manipulation portions  116  and  123  are minimized as illustrated herein, phone numbers, text, etc. can be input through a touch screen provided at the display  113 . 
         [0048]    The interface  124  serves as a path which allows the mobile terminal  100  to exchange data with external devices. For example, the interface  124  may be used in a wired or wireless manner, and may be at least one of a connection terminal to which an earphone is connected, a port for a local communication (e.g., infrared data (IrDA) port, Bluetooth port, wireless Lan port, etc.), or a power supply terminal for supplying power to the mobile terminal  100 . The interface  124  may be a card socket for receiving an external card such as a Subscriber Identification Module (SIM), a User Identity Module (UIM) or a memory card for storing information, etc. 
         [0049]    The power supply unit  125  is mounted at the rear case  121  so as to supply power to the mobile terminal  100 . 
         [0050]    The power supply unit  125  may be implemented as a rechargeable battery, for example, and be detachably coupled to the mobile terminal for charging and discharging operations. 
         [0051]      FIG. 2  is a rear perspective view of the mobile terminal  100  of  FIG. 1 . 
         [0052]    Referring to  FIG. 2 , a second image input unit  127 , a second audio output unit  130 , a broadcast signal receiving antenna  131 , etc. may be additionally disposed at the rear case  121 . 
         [0053]    The second image input unit  127  has a shooting direction substantially opposite to a direction of the first image input unit  115  (see  FIG. 1 ). The second image input unit  128  may be implemented as a camera having a pixel density different from that of the first image input unit. 
         [0054]    For example, the first image input unit  115  has low pixel density so that an image of the user&#39;s face can be captured and then transmitted without any problem in case of a video call, while the second image input unit  127  preferably has high pixel density since it is mainly used for when an image of a general object is captured but the image is not immediately transmitted. 
         [0055]    A flash  128  and a mirror portion  129  may be additionally disposed adjacent to the second image input unit  127 . When capturing an object by using the second image input unit  127 , the flash  128  throws a flash of light on the object. When the user captures an image of himself/herself by using the second image input unit  127 , the mirror portion  129  can be used for the user to look at himself/herself therein. 
         [0056]    The second audio output unit  130  may be implemented as a stereo together with the first audio output unit  114  (see  FIG. 1 ) or may be used to talk in a speakerphone mode. 
         [0057]    At least one side of the rear case  121  may be provided with the antenna  131  for receiving broadcast signals in addition to an antenna for communication. The antenna  131  may be installed to be extendable from the rear case  121 . 
         [0058]    So far, it is explained that the first manipulation portion  116 , etc. is mounted on the front case  111  and the second manipulation portion  123 , etc. is mounted on the rear case  121 . However, such is not limited thereto. For example, the second manipulation portion  123  may be disposed at the front case  111  so as to be adjacent to the first manipulation portion  116 . 
         [0059]    Further, even if the second image input unit  127  is not provided, since the first image input unit  115  is rotatably formed, it may be configured to be capable of shooting in a direction that includes a shooting direction of the second image input unit  127 . 
         [0060]      FIG. 3  is an exploded perspective view of the mobile terminal  100  of  FIG. 1 . 
         [0061]    Referring to this drawing, a window  140  is coupled so as to cover one surface of the front case  111 . The window  140  covers one surface of the display module  200  so that visual information output from the display module  200  is recognized from the outside. The display module  200  and the window  140  constitute the display  113  (see  FIG. 1 ). 
         [0062]    The window  140  may be configured to recognize a user&#39;s touch. In this case, the window  140  may receive an input of information (e.g., a command, a signal, and the like) by a user&#39;s touch. 
         [0063]    The window  140  may have an area corresponding to the display module  120  and is formed of a light transmitting material. The window  140  may have an opaque region where light is not transmitted or light transmission rate is very low. For instance, edges of the window  140  may undergo a surface treatment for blocking any light transmission. 
         [0064]    A manipulation pad  116   a  may be formed on the front case  111 , in correspondence to the first manipulation portion  116 . The manipulation pad allows the user to perform a touch or press operation thereon. 
         [0065]    The manipulation pad may function as a manipulation area at a portion of the window  140 . 
         [0066]    A sound hole  114   b , a window hole  112   b , and a video window may be formed at the front case  111 . 
         [0067]    The sound hole  114   b  is formed to correspond to the audio output unit  114 , and outputs audio sounds (e.g., ringtones, music, and the like) of the mobile terminal to the outside. The window hole  112   b  may be formed to correspond to the display  113 . A light-transmissive image window may be formed to correspond to the first image input unit  115  (see  FIG. 1 ). 
         [0068]    The display module  200 , a speaker module  114   a , a camera module  115   a , and a switch may be mounted on the rear case  121 . 
         [0069]      FIG. 4  is a conceptual diagram of a stereoscopic image display method related to an embodiment of the present invention.  FIGS. 5   a  and  5   b  are conceptual diagrams of 2D and 3D operation modes of a display module related to an embodiment of the present invention. 
         [0070]    The display module  200  according to an embodiment of the present invention includes a main liquid crystal panel  220  and a barrier panel  230 . Although descriptions of the elements such as a case and a driver are omitted, it does not mean that the omitted elements are not necessary for embodying the invention. 
         [0071]    Left-eye pixels L for displaying image information for the left-eye and right-eye pixels R for displaying image information for the right eye are alternately formed on the main liquid crystal panel  220 . A backlight  210  may be disposed at the backside of the main liquid crystal panel  220  to supply light. 
         [0072]    The backlight  210  may be used as a source of images to be provided to the user through the main liquid crystal panel  220  and the barrier panel  230 . The backlight  210  is disposed in such a manner as to enclose the outer surface of a first substrate  221  of the main liquid crystal panel  220  or the side surface of the main liquid crystal panel  220 , and supplies light to the main liquid crystal panel  220  through a light guide plate (not shown). The backlight  210  may include a light guide plate (not shown), a light source, a reflective plate, and an optical sheet. Particularly, the light source may be configured by using, but not limited to, a PDP, an OLED, an LED, a cold cathode ray tube, and a mechanism having the same function as those listed above. 
         [0073]    A detailed description of the backlight  210  will be omitted because a variety of techniques associated with the backlight  210  are well known. 
         [0074]    A parallax barrier panel  230  is disposed between the main liquid crystal panel  220  and an observer  10  or between the main liquid crystal panel  220  and the backlight  210  to transmit and block light at predetermined positions, and consists of slit portions T and barrier portions B for selectively transmitting and blocking light emitted from the left- and right-eye pixels L and R. The slit portions T and the barrier portions B alternate with each other. 
         [0075]    Of light emitted from the backlight  210 , light L 1  passed through the left-eye pixels L of the main liquid crystal panel  100  reaches the left eye LE of the observer  10  via the slit portions T of the parallax barrier panel  230 , and light R 1  passed through the right-eye pixels R of the main liquid crystal panel  220  reaches the right eye RE via the slit portions T of the parallax barrier panel  230 . The image displayed through the left- and right-eye pixels includes enough parallax information for the observer to be consciously aware of it, thus making it possible for the observer  10  to recognize the 3D stereoscopic image. 
         [0076]    In the 2D mode, the barrier panel  230  transmits light across the entire surfaces without performing any operation. On the other hand, in the 3D mode, a transparent zone functioning as the slit portions B for transmitting light and a barrier zone functioning as the barrier portions T for blocking light appear in stripes. 
         [0077]    As shown in  FIGS. 5A and 5B , the main liquid crystal panel  220  includes a pair of first and second substrates  221  and  223  attached together so that they face each other, with a liquid crystal layer  222  interposed therebetween. 
         [0078]    A plurality of pixels with their own orientations may be arranged between the two substrates  221  and  223 . Each of the pixels may include a transparent pixel electrode of the first substrate  221  and a transparent common electrode of the second substrate  223  may be disposed to face each other, with liquid crystals interposed therebetween. 
         [0079]    An image signal voltage may be selectively applied to the pixel electrode by a corresponding thin film transistor (TFT). The second substrate  223  is provided with red, green, and blue (RGB) color filters and a black matrix filling the gaps between the RGB color filters, for example, corresponding to each pixel, and the common electrode is formed to cover the black matrix. 
         [0080]    Accordingly, when an image signal voltage is applied to the pixel electrode of a selected pixel by the switching operation of the thin film transistor, a voltage difference is generated between the pixel electrode and the common electrode, and this drives liquid crystal molecules having optical anisotropy and polarization properties, thereby producing difference in transmittance. As light of the backlight  210  passes through the main liquid crystal panel  220 , a variety of planar color images are displayed in accordance with a difference in transmittance between the pixels and a color combination of the RGB color filters. Although an LCD panel is used as the main liquid crystal panel  220  by way of example, a Braun tube, a plasma display panel, an OLED display panel, and other display panels may also be used to implement the main liquid crystal panel. 
         [0081]    Although the barrier panel  230  includes first and second barrier substrates  233  and  235  bonded together to face each other, with a second liquid crystal  234  interposed therebetween, the barrier panel  230  is different from the main liquid crystal panel  220  in that, for every pixel, a transparent barrier electrode is formed on an inner surface of the first barrier substrate  233  and a transparent common electrode is provided on an inner surface of the second barrier substrate  235 . If the liquid crystal layer  234  is formed in a twisted nematic type, a liquid crystal driving voltage is applied to the barrier electrode in the 3D mode only. 
         [0082]    Moreover, in the display module  200 , for example, polarization plates may be respectively attached to an outer surface of the second substrate  223  of the main liquid crystal panel  220 , between the main liquid crystal panel  220  and the barrier panel  230 , and to the backside of the first barrier substrate  233  of the barrier panel  230 . 
         [0083]    As such, the display module  200  including the barrier panel  230  maintains a normal white condition across the entire surfaces of the barrier panel  230  in the 2D mode of  FIG. 5A  in which no voltage is applied to the barrier electrode of the barrier panel  230  and merely transmits light emitted from the backlight  210 . As a result, the viewer can see a planar image of the main liquid crystal panel  220 . While the description given herein is about normal white, normal white and normal black may be selectively formed in accordance with the display ratio between 2D and 3D. 
         [0084]    On the other hand, in the 3D mode of  FIG. 5B  in which a liquid crystal driving voltage is applied to the barrier electrode, only liquid crystals between the barrier electrode and the common electrode are driven. Thus, the corresponding portions serve as a barrier zone for displaying black to block light, and the portions formed therebetween serve as a transparent zone for displaying white to transmit light. Consequently, the barrier zone and the transparent zone function as the barrier portions B and the slit portions T, respectively, thus allowing the observer to recognize an image of the main liquid crystal panel  220  in a stereoscopic manner. 
         [0085]    As such, the display module  200  is able to switch between the 2D and 3D modes by on/off operations of the barrier electrode of the barrier panel  230 . 
         [0086]      FIG. 6  is a conceptual diagram illustrating a lamination structure of the barrier panel  230  (see  FIG. 5A ), refractive portion  240 , and main liquid crystal panel  220  (see  FIG. 5A ) of the display module related to an embodiment of the present invention. 
         [0087]    The refractive portion  240 , which is formed of a plurality of layers, includes at least one glass substrate  223  and  233 . Additionally, it may include an adhesion layer  242  or a polarization layer  241 . The refractive portion  240  is disposed between the main liquid crystal panel and the barrier panel. More specifically, the refractive portion  240  is disposed between the color filters  222   a  of the main liquid crystal panel and the liquid crystal layer  234  on which the barriers of the barrier panel are formed. 
         [0088]    The glass substrate  223  and  233  may be the second substrate  223  of the main liquid crystal panel or the first barrier substrate  233  of the barrier panel. 
         [0089]    In general, in the design of a stereoscopic image display using a parallax barrier, the viewing distance D (see  FIG. 4 ) is proportional to the rear distance S (see  FIG. 4 ), and inversely proportional to the pitch P (see  FIG. 4 ) of a pixel. In an example, provided that the interocular distance between the left and right eyes of the observer  10  is 65 mm, the stereoscopic image display can be designed by the following Equation: 
         [0000]        D=S [( E+P )/ P]   [Equation 1]
 
         [0090]    The rear distance calculated by Equation 1 is as shown in the following Table 1: 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 rear distance 
                 rear distance 
               
               
                 display 
                   
                 (refractive 
                 (refractive 
               
               
                 panel size 
                 resolution 
                 index) 
                 index: 1.5) 
               
               
                   
               
             
             
               
                  10″ 
                 XGA(1024*768) 
                 0.70 mm (1.8) 
                 0.58 mm 
               
               
                   
                 WXGA(1280*800)  
                 0.63 mm (1.9) 
                 0.50 mm 
               
               
                 8.9″ 
                 XGA(1024*768) 
                 0.62 mm (1.8) 
                 0.52 mm 
               
               
                   
                 WXGA(1280*800)  
                 0.56 mm (1.9) 
                 0.44 mm 
               
               
                   
               
             
          
         
       
     
         [0091]    As shown in the above table, in a 10-inch display panel, when the refractive index of the refractive portion  240  is 1.5, the viewing angle is 380 mm, and the resolution is WXGA(1280*800), the rear distance is only 0.50 mm. If at least one glass substrate  223  and  233 , the polarization layer  241 , and the adhesion layer  242  are formed within the above rear distance, each of the components do not have sufficient thickness. Especially, the glass substrate  223  and  233  does not have sufficient rigidity, and therefore is easily damaged. This drawback acts as a barrier element because it causes limitations in designing a terminal. 
         [0092]    In order for the glass substrate  223  and  233  to have sufficient rigidity, it must have a rear distance of at least 0.55 m. Also, if the rear distance is 0.75 mm or greater, it is difficult to make a terminal smaller in size. Accordingly, as shown in Table 1, the refractive index of the refractive portion  240  is preferably 1.8 or more. With a refractive index of 2.3 or more, the resolution of a three-dimensional object may be lowered, and the thickness of the body of a terminal may be increased, which is contrary to the trend of small-sized terminals. Therefore, at least one of the plurality of layers constituting the refractive portion have a refractive index of 1.8≦n≦2.3 so that the refractive portion can have a high refractive index as described above. 
         [0093]    In order to increase the refractive index of the glass substrate  223  and  233 , it has to contain at least Nb 2 O 5 , BaO, and TiO 2 . Here, if the glass substrate  223  and  233  contains 40 to 50% by weight of Nb 2 O 5 , 17 to 26% by weight of BaO, and 1 to 6% by weight of TiO 2 , the glass substrate  223  and  233  may have a refractive index of 1.8 or more. 
         [0094]    The refractive portion  240  may further include at least one polarization layer  241 . Because of this, the overall refractive index of the refractive portion  240  may be designed such that optimum resolution and higher viewing angle can be achieved. 
         [0095]    In order to increase the refractive index of the polarization layer  241 , the polarization layer  241  includes at least one intermediate layer  241   b  of an inorganic material. Different layers  241   a  and  241   c  of an organic or inorganic material may be formed above and below the intermediate layer  241   b . The intermediate layer  241   b  of an inorganic material requires sufficient thickness because it may be provided with fine grooves without substantially exposing the substrate surface. In an example, the intermediate layer  241   b  may have a thickness of less than 10 μm, preferably less than 5 μm, more preferably, less than 1 μm. 
         [0096]    The intermediate layer  241   b  may be preferably a silicon oxide, a metal oxide, or a compatible mixture and/or combination thereof. That is, the inorganic intermediate layer  241   b  may be formed by a material selected from the group consisting of SiO, SiO 2 , Al 2 O 3 , ZrO 2 , TiO 2 , GeO 2 , and mixtures and combinations thereof. 
         [0097]    As such, the polarization layer  241  and the intermediate layer  241   b , which are formed of an inorganic material as described above, can have a strong bond with the glass substrate  223  and  233  made of especially SiO 2 , an inorganic glass material, and an organic polymer material. This leads to an increase in the overall refractive index of the refractive portion  240 . 
         [0098]    The refractive portion  240  may further include at least one adhesion layer  242 . Because of this, the overall refractive index of the refractive portion  240  may be designed such that optimum resolution and higher viewing angle can be achieved. 
         [0099]    The adhesion layer  242  may be formed of an organic or inorganic adhesion layer containing glass fibers. 
         [0100]    The inorganic adhesion layer has a thickness in the range of 100 nm to 2□, more preferably in the range of 200 nm to 1 μm. A material for forming the inorganic adhesion layer may be a silicon compound such as SiO 2 , SiN, etc. or an aluminum compound such as Al 2 O 3  so that the inorganic adhesion layer has a minimum refractive index of 1.5 or more. 
         [0101]    Besides, a material for the organic adhesion layer may include thermoplastic resin (acrylic resin), polyester resin (polyethyleneterephthalate, etc.), methacrylic acid resin, polyamide resin, polyimide resin, polyetherimide resin, polyacetal resin, polyethersulfone, polyvinyl alcohol and a derivative thereof (polyvinyl butyral, etc.), polyphenylene ether, norbornene resin, isobutylene-maleic anhydride copolymer resin, cyclic olefin resin), non-photosensitive thermosetting resin (alkyd resin, aromatic sulfonamide resin, urea resin, melamine resin, benzoguanamine resin), or photosetting resin. Each of these materials has a refractive index of at least 1.5. 
         [0102]    As described above, the above-described display module and a mobile terminal including the same are not limited to the configuration and method of the embodiments described as above, but the embodiments may be configured by selectively combining all the embodiments or some of the embodiments so that various modifications can be made. 
         [0103]    The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. 
         [0104]    As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.