Abstract:
The present invention relates to a display apparatus comprising front display unit ( 10 ) and rear display unit ( 50 ), wherein the front display unit ( 10 ) and the rear display unit ( 50 ) are arranged such that an image on the rear display unit ( 50 ) is visible through a portion of the front display unit ( 10 ). The front display unit ( 10 ) comprise: a display panel ( 20 ); a front backlight ( 30 ) which is arranged behind the display panel ( 20 ), and which includes a first light guide plate ( 36 ) having a projection window ( 16 ) through which an image on the rear display unit ( 50 ) is visible, first light sources ( 38 ) arranged along the circumference of the first light guide plate ( 36 ), and a reflection sheet ( 39 ) arranged at the rear surface of the first light guide plate ( 36 ) to reflect light and having an image hole ( 18 ) formed at the region thereof that corresponds to the projection window ( 16 ); a rear backlight ( 40 ) arranged behind the front backlight ( 30 ) and including a second light guide plate ( 42 ) corresponding to the projection window ( 16 ) and second light sources ( 44 ) arranged along the circumference of the second light guide plate ( 42 ); and a rear optical shutter ( 48 ) arranged behind the second light guide plate ( 24 ). The rear optical shutter ( 48 ) is made of a transparent material, such that the rear display unit and the front display unit cooperate with one another to display a combined image. The entire screen of the front display unit is capable of displaying an image, without any disconnection of the image, when the rear optical shutter is closed.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a display apparatus which includes front and rear display units cooperating with each other to display a combined image and, more particularly, to a display apparatus which permits a front display unit to display an image on an entire screen thereof without disconnection of the screen. 
       BACKGROUND ART 
       [0002]    Generally, in a slot machine using a rotational reel display unit, a liquid crystal display is used to induce interest in a game and display more colorful images. Typically, the liquid crystal display is disposed on a front side of the game machine, and an opening is formed on a light guide plate constituting a backlight unit of the liquid crystal display. Further, the opening is provided at the rear thereof with a rotational reel on which a reel band having symbol marks is mounted. With this configuration, a rear rotational reel display unit is viewed through the opening of the light guide plate and a game-related image is display through the liquid crystal display at the front side of the game machine, thereby inducing interest in the game. 
         [0003]    However, in such a game machine, light is not emitted through the opening of the light guide plate, causing disconnection of an image displayed on the liquid crystal display. For example, when a game-related image is displayed through the liquid crystal display at the front side of the game machine, with the rear rotational reel display unit stopped, it is difficult to display the image since a backlight unit is not present in a region through which the rotational reel display unit is viewed. As a result, the game machine provides only a very restrictive and disconnected screen image in displaying game results and guide messages through the front liquid crystal display. 
         [0004]    Moreover, although the rotational reel display unit at the rear side of the game machine is illuminated by a separate lighting lamp, the rotational reel display unit is always exposed through the opening of the light guide plate even in the case in which the lighting lamp is turned off. This configuration provides a coarse appearance to the display apparatus while a game is not played. 
       DISCLOSURE 
     Technical Problem 
       [0005]    The present invention is conceived to solve such problems in the art, and provides a display apparatus configured to display a combined image through cooperation between front and rear display units, wherein the rear display unit may be viewed through a projection window and the entirety of the front display unit may be illuminated to allow the front display unit to display an image on the entire screen thereof without disconnection of the screen while selectively shielding the rear display unit, so that the display apparatus may display game results, guide messages, and other game-related images on the front display unit without any restriction and may enhance screen display quality even when a game is not played. 
         [0006]    In addition, the present invention provides a display apparatus which may selectively shield the front display unit in order to indicate whether a game is played or not. 
         [0007]    Further, the present invention provides a display apparatus in which a light guide plate of a front backlight unit is formed with a pattern region and a non-pattern region to provide a projection window without cutting the light guide plate, thereby simplifying a manufacturing process of the light guide plate, improving brightness of the front backlight unit, and suppressing light interference between the front backlight unit and the rear backlight unit on the projection window. 
       Technical Solution 
       [0008]    In accordance with one aspect of the present invention, a display apparatus includes a front display unit  10  and a rear display unit  50  disposed behind the front display unit  10  such that an image of the rear display unit  50  can be viewed through part of the front display unit  10 , wherein the front display unit  10  includes a display panel  20 ; a front backlight unit  30  including a first light guide plate  36  disposed behind the display panel  20  and having a projection window  16  through which the rear display unit  50  is visible, a first light source  38  arranged along the circumference of the first light guide plate  36 , and a reflective sheet  39  placed on a backside of the first light guide plate  36  to reflect light and opened at a region thereof corresponding to the projection window  16  to form an image hole  18 ; a rear backlight unit  40  including a second light guide plate  42  disposed at a place corresponding to the projection window  16  behind the front backlight unit  30 , and a second light source  44  arranged along the circumference of the second light guide plate  42 ; and a rear optical shutter  48  disposed behind the second light guide plate  24   
         [0009]    In some embodiments, the rear display unit  50  may be a rotational reel display unit having a plurality of variable image arrays. 
         [0010]    In some embodiments, the rear display unit  50  may include one of an LCD, PDP, OLED, and AMOLED. 
         [0011]    In some embodiments, the rear display unit  50  may be a picture or an object displaying an image. 
         [0012]    In some embodiments, when the rear display unit  50  is the rotational reel display unit or the picture or object displaying an image, the display apparatus may further include a rear display lighting unit  56  which illuminates the rear display unit  50 . 
         [0013]    In some embodiments, the display panel  20  may be a liquid crystal panel, which includes a TFT substrate  26 , a color filter  24 , and liquid crystals encapsulated between the TFT substrate  26  and the color filter  24  bonded to each other. 
         [0014]    In some embodiments, the projection window  16  may be formed by cutting a part of the first light guide plate  36  corresponding to the rear display unit  50 . 
         [0015]    In some embodiments, the first light guide plate  36  includes a pattern region  36   a  formed on a region thereof excluding the projection window  16  and having a pattern printed thereon, and a non-pattern region  36   b  formed on a region of the projection window  16  and having no pattern. 
         [0016]    In some embodiments, the display apparatus further includes a front optical shutter  46  disposed behind the display panel  20 . 
         [0017]    In some embodiments, the front optical shutter  46  and the rear optical shutter  48  may be liquid crystal shutters including polymer dispersed liquid crystals (PDLC). 
         [0018]    In some embodiments, the first and second light sources may be CCFLs or LEDs. 
       Advantageous Effects 
       [0019]    According to the present invention, the front display unit of the display apparatus is equipped with a front backlight unit having a projection window through which the rear display unit is visible, a rear backlight unit is placed corresponding to the projection window, and a rear optical shutter is placed behind the rear backlight unit. With this configuration, when the rear optical shutter is switched to a transparent state, the rear display unit may be viewed through the light guide plate of the rear backlight unit to display a combined image in cooperation with the front display unit. Further, when the rear optical shutter is shielded, the rear backlight unit illuminates a region of the front display unit corresponding to the projection window, with an image of the rear display unit completely shielded, so that the entirety of the front display unit can be illuminated, thereby allowing the front display unit to display an image on the entire screen thereof without disconnection of the screen. As a result, the display apparatus may realize display of game-related images in various ways in higher quality by allowing the game-related images to be displayed through the entire screen of the front display unit while completely blocking the rear display unit when a game is not played. 
         [0020]    In addition, according to the present invention, the display panel is provided at the rear side thereof with a front optical shutter which is used to switch the front optical shutter to a transparent state or to a shielded state in order to indicate whether a game is played by controlling on/off of the overall screen of the display apparatus. 
         [0021]    Further, according to the present invention, the light guide plate of the front backlight unit is formed with a pattern region and a non-pattern region to provide a projection window without cutting the light guide plate, thereby simplifying a manufacturing process of the light guide plate, improving brightness of the front backlight unit through an increase in total reflection area within the light guide plate, and suppressing light interference between the front backlight unit and the rear backlight unit by light shielding between the pattern region and the non-pattern region. 
         [0022]    Furthermore, such effects of the present invention may be usefully applied not only to game machines such as slot machines, but also to a technique for embodying 3-dimensional and 2-dimensional images based on combination of front and rear display units, and other image display techniques based on combination of the front and rear display units. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a perspective view of a front display unit in accordance with the present invention; 
           [0024]      FIG. 2  is a sectional view of a display apparatus in accordance with one embodiment of the present invention; 
           [0025]      FIG. 3  is a sectional view of a display apparatus in accordance with another embodiment of the present invention; 
           [0026]      FIG. 4  is a front view of a first light guide plate in accordance with another embodiment of the present invention; and 
           [0027]      FIG. 5  is a cross-sectional view of the first light guide plate taken along line A-A′ of  FIG. 4 . 
           [0000]    
         
           
                 
               
                 
                 
               
             
                 
                     
                 
                 
                   &lt;Description of reference numerals of main parts of the drawings &gt; 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                   10: front display unit 
                   12: front backlight unit housing 
                 
                 
                   14: rear backlight unit housing 
                   16: projection window 
                 
                 
                   18: image hole 
                   20: display panel 
                 
                 
                   22: polarizer film 
                   24: color film 
                 
                 
                   26: TFT substrate 
                   28: polarizer film 
                 
                 
                   30: front backlight unit 
                   32: prism sheet 
                 
                 
                   34: diffusive sheet 
                   36: first light guide plate 
                 
                 
                   36a: pattern region 
                   36b: non-pattern region 
                 
                 
                   38: first light source 
                   39: reflective sheet 
                 
                 
                   40: rear backlight unit 
                   42: second light guide plate 
                 
                 
                   44: second light source 
                   46: front optical shutter 
                 
                 
                   48: rear optical shutter 
                   50: rear display unit 
                 
                 
                   52: rotational reel 
                   54: reel band 
                 
                 
                   56: rear display lighting unit 
                 
                 
                     
                 
               
            
           
         
       
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0028]    Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
         [0029]    The present invention relates to a display apparatus which displays a combined image through cooperation between a front display unit and a rear display unit disposed behind the front display unit. Such a display apparatus may be applied in various ways, for example, game machines such as slot machines, game machines which display images through combination of front and rear displays, 3D image display apparatuses, electronic frames, and the like. 
         [0030]    According to one embodiment, a liquid crystal display and a rotational reel display unit may be used as front and rear display units, respectively. The rotational reel display unit may be configured to provide variable display of symbol marks printed on a reel band and to allow winning of a game to be determined according to combination of the symbol marks. 
         [0031]    In another embodiment, the rear display unit may be replaced by other types of display unit. For example, typical display apparatuses such as a liquid crystal display (LCD), plasma display panel (PDP), organic light emitting diode (OLED), active matrix organic light emitting diode (AMOLED), and the like, may be provided as the rear display unit. In a further embodiment, a picture or an object (for example, jewelry) displaying a certain image may be provided as the rear display unit. 
         [0032]      FIG. 1  is a perspective view of one example of a front display unit in accordance with the present invention, and  FIGS. 2 and 3  are schematic views of display apparatuses in accordance with embodiments of the invention. Referring to  FIG. 1 , the front display unit  10  includes a display panel  20 , a front optical shutter  46 , a front backlight unit  30 , a rear backlight unit  40 , and a rear optical shutter  48  arranged to form a multilayer structure. As shown in  FIGS. 2 and 3 , a rear display unit  50  is placed behind the front display unit  10 .  FIG. 2  shows a rotational reel display unit according to one embodiment of the invention and  FIG. 3  shows a rotational reel display unit according to another embodiment of the invention. 
         [0033]    Referring to  FIG. 2 , when a rotational reel display unit is provided as the rear display unit  50 , the rotational reel display unit has a structure in which a reel band  54  is attached to an outer periphery of a rotational reel  52  and is printed with symbol marks (not shown). Further, a rear display lighting unit  56  is placed inside or outside the rotational reel  52  to illuminate the symbol marks. Accordingly, the rear display unit  50  may be viewed by operating the rear display lighting unit to illuminate the rotational reel  52 , and a game result may be determined based on a combination of the symbol marks, which may be viewed through the front display unit  10  when rotation of the rotational reel  52  is stopped. 
         [0034]    Referring to  FIG. 3 , the rear display unit  50  may be realized by a display unit such as an LCD, PDP, OLED, AMOLED, and the like. In this case, a game-related image is displayed through the display unit at the rear side and a gamer views the image corresponding to the game through the front display unit  10 . Here, since the display unit provided as the rear display unit  50  is the same as a typical display apparatus, a detailed description of the display unit including a backlight unit will be omitted herein. 
         [0035]    In the embodiment of  FIG. 1 , the display apparatus is illustrated as being applied to a slot machine, but the display apparatus according to the present invention may be embodied by a structure in which the front display unit  10  has a plurality of visible regions and 3D images can be displayed through cooperation between the front and rear display units  10 ,  50 . 
         [0036]    Referring to  FIG. 1 , the display panel  20  may be a liquid crystal panel. The display panel  20  includes a TFT substrate  26 , a color filter  24 , and polarizer films  22 ,  28  provided to front and rear sides of a panel provided by bonding the TFT substrate  26  to the color filter  24 . As in a typical liquid crystal panel, the TFT substrate  26  is an array substrate which includes pixel regions and pixel electrodes arranged in a matrix, gate wires, and source wires arranged in transverse and longitudinal directions, and the color filter  24  is a glass substrate on which R, G and B patterns are printed or R, G and B films are coated. Although not shown in the drawings, a drive IC is mounted on a lateral side of the panel provided by bonding the TFT substrate  26  to the color filter  24 , and liquid crystals are encapsulated between the TFT substrate  26  and the color filter  24 . Each of the polarizer films  22 ,  28  is printed with patterns orthogonal to one another and serves to permit realization of various colors through the color filter by determining penetration and blocking of light when a polarizing direction of the light is changed according to movement of the liquid crystals. Although not shown in the drawings, the display panel  20  may further include other components, such as a protective film, a glass substrate, and the like. 
         [0037]    The front optical shutter  46  is placed between the display panel  20  and the front backlight unit  30 . The front optical shutter  46  allows light from the front backlight unit  30  to pass therethrough or blocks the light therefrom, and may include polymer dispersed liquid crystals (PDLC). The PDLC panel includes liquid crystals dispersed within a polymer without using a polarizer film. When voltage is not applied to the front optical shutter, the liquid crystals are non-uniformly arranged in the front optical shutter, so that the front optical shutter blocks light. When voltage is applied thereto, the liquid crystals are uniformly arranged, so that the front optical shutter is switched to a transparent state. With this configuration, the front optical shutter  46  blocks light from the front backlight unit  30  and the rear backlight unit  40  described below, thereby forcibly blocking display of the front display unit  10 . 
         [0038]    As shown in the drawings, the front backlight unit  30  includes optical sheets such as a prism sheet  32  and a diffusive sheet  34 , a first light guide plate  36 , first light sources  38 , and a reflective sheet  39 . The prism sheet  32  is an optical sheet for collecting light and the diffusive sheet  34  is an optical sheet for dispersing light in order to obtain uniform brightness. Such optical sheets may be selectively used or replaced by other optical sheets. Further, the front backlight unit may further include a protective sheet and the like. As shown in the drawings, such optical sheets are partially formed with image holes  18  through which the rear display unit  50  is visible. 
         [0039]    The first light guide plate  36  receives light from the first light sources  38  through a thickness plane and emits light through a surface of the panel, and is formed of transparent acryl or the like. Each of the first light sources  38  may be embodied by a cold cathode fluorescent lamp (CCFL) as shown in  FIG. 1 , or may be embodied by an LED as shown in  FIGS. 2 and 3 . Further, the first light sources  38  are disposed at peripheral sides of the first light guide plate  36 . In this embodiment, the first light sources  38  are illustrated as being disposed at upper and lower sides of the first light guide plate  36 . Alternatively, the first light sources  38  may also be disposed at right and left sides of the first light guide plate  36 . 
         [0040]    As shown in the drawings, the first light guide plate  36  is formed with projection windows  16  through which the rear display unit  50  is visible. The projection windows  16  are non-luminous regions, and light of the front backlight unit  30  is not generated from regions having the projection windows  16 . Accordingly, it is possible to view the rear display unit  50  through the projection windows  16  while a screen is displayed on the display panel  20 . 
         [0041]    Meanwhile, in the embodiment of  FIG. 1 , the projection windows  16  are formed by cutting three central regions of the first light guide plate  36  to form openings on the first light guide plate. However, in some embodiments, the projection windows  16  may be formed without cutting the central regions of the first light guide plate  36 , and this technique will be described below with reference to  FIGS. 4 and 5 . 
         [0042]    The reflective sheet  39  is disposed at the rear of the first light guide plate  36  to reflect light. As in the optical sheets described above, the reflective sheet  39  is opened at three regions corresponding to the projection windows  16  to form the image holes  18 . The reflective sheet  39  may be realized by a protective glass which includes a reflective film attached to an overall surface thereof. 
         [0043]    In order to allow the front display unit  10  to display an image on an entire screen thereof, the display apparatus according to the embodiments of the present invention further includes a separate rear backlight unit  40  and a separate rear optical shutter  48  disposed behind the front backlight unit  30 . As shown in  FIGS. 2 and 3 , the display panel  20  and the front backlight unit  30  are placed inside a front backlight unit housing  12 , and the rear backlight unit  40  and the rear optical shutter  48  are disposed within a separate rear backlight unit housing  14 . Advantageously, the rear backlight unit housing  14  may be assembled to an opening formed on a backside of the front backlight unit housing  12 . 
         [0044]    The rear backlight unit  40  includes second light guide plates  42  placed corresponding to the projection windows  16  of the front backlight unit  30 , and second light sources  44  disposed at peripheral sides of each of the second light guide plates  42 . Like the first light guide plate  36 , the second light guide plates  42  may be realized by transparent panels, and the second light sources  44  may be realized by CCFLs or LEDs. Although the second light sources  44  are illustrated as being disposed at upper and lower sides of the corresponding second light guide plates  42 , the second light sources  44  may be disposed at right and left sides of the second light guide plate  42 . 
         [0045]    Here, in order to achieve the objectives of the present invention, the rear backlight unit  40  is configured to illuminate the front display unit  10  and is viewable. Thus, the rear backlight unit  40  is not provided at the backside thereof with any reflective sheet. Instead, as shown in the drawings, the rear backlight unit  40  is provided at the backside thereof with a rear optical shutter  48 . Although the rear optical shutter  48  may be realized by various types of optical devices, the rear optical shutter  48  may be realized by PDLC, as in the front optical shutter  46 . 
         [0046]    When the rear optical shutter  48  is in a transparent state and the rear backlight unit  40  is turned off, the rear display unit  50  is viewed through the second light guide plates  42  of the rear backlight unit  40 . As a result, the display apparatus may display a combined image of the front and rear display units  10 ,  50 . Further, when the rear optical shutter  48  is in a shielded state and the rear backlight unit  40  is turned on, the rear display unit  50  is completely blocked from a user&#39;s view and the rear backlight unit  40  illuminates the projection windows  16  of the front backlight unit  30 , so that a clear image may be displayed throughout the screen of the front display unit  10 . 
         [0047]    Although not shown in the drawings, the display apparatus may further include an optical shutter on the front side of the rear backlight unit  40 . The optical shutter on the front side of the rear backlight unit  40  is operated to completely shield light of the rear backlight unit  40 . 
         [0048]      FIG. 4  is a front view of a first light guide plate in accordance with another embodiment of the present invention, and  FIG. 5  is a cross-sectional view of the first light guide plate taken along line A-A′ of  FIG. 4 . 
         [0049]    Referring to these drawings, in this embodiment, the first light guide plate  36  is formed with projection windows  16  without cutting the central regions thereof. 
         [0050]    Referring to  FIG. 4 , the first light guide plate  36  has a pattern region  36   a  and a non-pattern region  36   b . In the first light guide plate  36 , a predetermined pattern is printed only on a region through which the rear display unit  50  is not viewed, that is, on a region on which the projection windows  16  will not be formed. The pattern formed on the pattern region  36   a  is typically the same as the pattern printed over the entire surface of the light guide plate, and serves to collect and refract light forwards when the light enters the light guide plate. For example, the pattern formed on the pattern region  36   a  may be a pattern of dots arranged in a matrix. Further, brightness of the light guide plate may be determined by adjusting distances between pattern rows and between pattern columns. In some embodiments, a combined pattern may be used to improve brightness and light uniformity of the light guide plate. 
         [0051]    The non-pattern region  36   b  has no pattern and is formed on a region of the first light guide plate  36  corresponding to the projection windows  16  through which the rear display unit  50  is visible. The non-pattern region  36   b  prevents light from being emitted through the front side thereof by total reflection of the light incident on the first light guide plate  36 . With this configuration, the first light guide plate  36  emits light only through the front side of the pattern region  36   a  without emitting light through the front side of the non-pattern region  36   b.    
         [0052]    Here, total reflection of light occurring within the non-pattern region  36   b  of the first light guide plate  36  cannot be observed from the outside, so that the non-pattern region  36   b  appears transparent. 
         [0053]    In this configuration of the first light guide plate  36 , since the central region of the light guide plate is not removed, the first light guide plate  36  may be manufactured by a simple process. Further, compared with the first light guide plate  36 , the central regions of which are removed as shown in  FIG. 1 , the first light guide plate  36  according to this embodiment provides an increased total reflection area, thereby improving brightness. This effect may reduce overall power consumption of the display apparatus through a reduction in power consumption of the first light source  38 . Further, a light shielding effect occurs between the pattern region  36   a  and the non-pattern region  36   b , thereby significantly suppressing light interference between the front backlight unit  30  and the rear backlight unit  40 . 
         [0054]    Although some embodiments have been described herein, it should be understood by those skilled in the art that these embodiments are given by way of illustration only, and that various modifications, variations and alterations can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be limited only by the following claims and equivalents thereof.