Patent Abstract:
A liquid crystal display device includes a liquid crystal display unit for displaying images, and a case in which the liquid crystal display unit is installed, the case being formed with an opening through which the liquid crystal display unit is slid into and out of the case.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a display device such as a liquid crystal display device.  
           [0003]    2. Description of the Related Art  
           [0004]    As an example of a conventional display unit, a conventional liquid crystal display device is illustrated in FIGS.  1  to  10 .  
           [0005]    The conventional liquid crystal display device includes a backlight unit  30  (see FIG. 1), a panel unit  50  (see FIG. 5), and a rear plate  26  (see FIG. 8).  
           [0006]    As illustrated in FIG. 1, the backlight unit  30  is comprised of lamps  15 , light-reflectors  16 , an optical sheet comprised of a lens film  22  and a light-diffusion film  23  (see FIG. 2), a light-reflection film  14 , a light-guide  13  (see FIG. 2), a rear frame  21 , and a front frame  31  (see FIG. 3).  
           [0007]    As illustrated in FIG. 5, the panel unit  50  is comprised of a plurality of flexible substrates  300  on each of which a driver IC is mounted, connector substrates  500 , and signal-processing substrates  400 . The connector substrates  500  and the signal-processing substrates  400  are mechanically and electrically connected to a liquid crystal display panel through the flexible substrates  300 .  
           [0008]    As illustrated in FIG. 6, the panel unit  50  is framed by a front bezel  40  formed centrally with an opening  61 .  
           [0009]    As illustrated in FIG. 8, on the rear plate  26  are mounted a conversion substrate  600  which receives external signals, converts the thus received signals into a desired form, and transmits the converted signals to the signal-processing substrate  400 , an inverter substrate  700  which supplies a desired voltage to the lamps  15 , and circuit substrates (not illustrated).  
           [0010]    As illustrated in FIG. 9, the rear plate  26  is mounted on a rear of a display unit  60 , and as illustrated in FIG. 10, the display unit  60  is fixedly sandwiched between a case front  70  and a case rear  80 . Thus, a liquid crystal display device is completed.  
           [0011]    Japanese Patent Application Publication No. 11-281963 suggests a method of fixing the backlight unit  30  and the panel unit  50  to each other.  
           [0012]    As illustrated in FIGS. 5 and 6, a frame of the backlight unit  30  is formed at an external sidewall thereof with a plurality of hooks  34  for horizontally supporting and positioning a liquid crystal display panel, and the front bezel  40  fixes the panel unit  50  onto the backlight unit  30 .  
           [0013]    Japanese Patent Application Publication No. 9-297542 suggests a method of fixing the display unit  60 .  
           [0014]    In the method, as illustrated in FIGS.  7  to  10 , the display unit  60  is comprised of the backlight unit  30  and the panel unit  50  both connected to each other through the front bezel  40 . The display unit  60  is designed to have such a flange that the display unit  60  is fixedly sandwiched between a front housing as the case front  70  and a rear housing as the case rear  80 .  
           [0015]    FIGS.  1  to  4  illustrate parts constituting the backlight unit  30  and steps of assembling the backlight unit  30 .  
           [0016]    As illustrated in FIG. 1, the light-reflection sheet  14 , the lamps  15  as a light source, and the light-reflectors  16  are all inserted into the rear frame  21 . Each of the lamps  15  is temporarily fixed to the light-reflector  16  by means of a holder rubber  19 , and includes a lamp cable  20  extending from an end of the lamp  15 .  
           [0017]    As illustrated in FIG. 2, the light-guide  13 , the light-diffusion film  23  and the lens film  22  are mounted in this order on the light-reflection sheet  14  fixed in the rear frame  21 .  
           [0018]    Then, as illustrated in FIG. 3, the front frame  31  is fixed onto the rear frame  21  to thereby fix the light-guide  13 , the light-diffusion film  23  and the lens film  22  therebetween. The front and rear frames  31  and  21  are fixed to each other by insertion of the hooks  34  into hook holes  32  formed at an external surface of the front frame  31 , and further by screws  35 .  
           [0019]    Thus, as illustrated in FIG. 4, the backlight unit  30  is completed.  
           [0020]    FIGS.  5  to  7  illustrate parts constituting the display unit  60  and steps of assembling the display unit  60 .  
           [0021]    The front frame  31  is formed with ribs  37  for supporting a liquid crystal display panel. The panel unit  50  is mounted on the backlight unit  30  in dependence on the ribs  37 .  
           [0022]    As illustrated in FIG. 6, the signal-processing substrates  400  and the connector substrates  500  are positioned on a rear of the backlight unit  30  by bending the flexible substrates  300 . As an alternative, the connector substrates  500  may be fixed to sidewalls of the backlight unit  30  by perpendicularly bending the flexible substrates  300 .  
           [0023]    The panel unit  50  mounted on the backlight unit  30  is then fixedly sandwiched between the front bezel  40  and the backlight unit  30 , in which case, the front bezel  40  and the backlight unit  30  are fixed to each other by inserting the hooks  34  of the backlight unit  30  into hook holes  41  of the front bezel  40 , as illustrated in FIG. 7.  
           [0024]    FIGS.  8  to  10  illustrate parts constituting a liquid crystal display device and steps of assembling the same.  
           [0025]    As illustrated in FIG. 9, a power source connector  610  and an interface connector  620  are mounted on the conversion substrate  600 . As illustrated in FIG. 8, the inverter substrate  700  and the conversion substrate  600  are fixed onto the rear plate  26  by means of hooks  27  and screws  24 . The rear plate  26  is fixed on a rear of the display unit  60 , as illustrated in FIG. 9.  
           [0026]    As illustrated in FIGS. 8 and 9, the substrates are electrically connected to one another through connection cables  25 . A backlight cable is electrically connected to the inverter substrate  700 .  
           [0027]    Then, as illustrated in FIG. 10, the display unit  60  on which the conversion substrate  600  and the inverter substrate  700  have been mounted is fixedly sandwiched between the case front  70  and the case rear  80  by insertion of hooks  71  of the case front  70  into hook holes  81  of the case rear  80 , and further by screws  28 . Thus, there is completed a liquid crystal display device.  
           [0028]    As mentioned above, the conventional liquid crystal display device is fabricated as follows.  
           [0029]    First, there are assembled the backlight unit  30  comprised of the lamps  15 , the light-reflectors  16 , the optical sheet  22 - 23 , the light-reflection sheet  14 , the light-guide  13  and the frames  21  and  31 , and the panel unit  50  including a liquid crystal display panel to which the connection substrates  500  and the signal-processing substrates  400  are connected through the flexible substrates  300 . Then, the backlight unit  30  and the panel unit  50  are connected to each other through the front bezel  40  formed with the opening  61 , thereby forming the display unit  60 . Then, the rear plate  26  on which the conversion substrate  600 , the inverter substrate  700  and the circuit substrates are mounted is fixed onto a rear of the backlight unit  30 . Then, the display unit  60  is fixedly sandwiched between the case front  70  and the case rear  80 . Thus, there is fabricated the liquid crystal display device.  
           [0030]    As is obvious in light of the above-mentioned fabrication process of the conventional liquid crystal display device, the conventional liquid crystal display device is accompanied with problems that it has a lot of parts for fabrication, and fabrication process is quite complicated, because the fabrication process includes a plurality of steps of inverting parts or semi-products.  
           [0031]    In addition, an increase in the number of the parts for fabrication of a liquid crystal display device causes difficulty in preparing and delivering parts, and an increase in lead-time necessary for assembling a liquid crystal display device after parts are obtained. As a result, costs for fabrication of a liquid crystal display device are unavoidably up.  
           [0032]    Furthermore, since fabrication error in assembly of the units is accumulated, a resultant liquid crystal display device unavoidably have much reduced accuracy in fabrication.  
           [0033]    The above-mentioned problems are common to a display device other than a liquid crystal display device.  
         SUMMARY OF THE INVENTION  
         [0034]    In view of the above-mentioned problems in the conventional liquid crystal display device, it is an object of the present invention to provide a display device which can reduce the number of assembling steps for simplifying a fabrication process.  
           [0035]    In one aspect of the present invention, a display device including a display unit for displaying images, and a case in which the display unit is installed, the case being formed with an opening through which the display device is slid into and out of the case.  
           [0036]    It is preferable that the case is formed with a guide for supporting the display unit therewith.  
           [0037]    It is preferable that the case includes a cover for covering the opening therewith, the cover being formed as a part of the case.  
           [0038]    It is preferable that the cover is bendable for having a first position in which the cover does not close the opening, and a second position in which the cover closes the opening.  
           [0039]    The display device may further include a base plate on which the display unit is fixed.  
           [0040]    For instance, the display device is fabricated as an electroluminescence (EL) display device.  
           [0041]    In another aspect of the present invention, there is provided a liquid crystal display device including a liquid crystal display unit for displaying images, and a case in which the liquid crystal display unit is installed, the case being formed with an opening through which the liquid crystal display unit is slid into and out of the case.  
           [0042]    For instance, the liquid crystal display unit may be comprised of a liquid crystal display panel, a first substrate supplying a desired voltage to the liquid crystal display panel, a second substrate supplying a signal voltage to the first substrate, a backlight unit supplying backlight to the liquid crystal display panel, a third substrate acting as an interface, and a fourth substrate supplying a desired voltage to the backlight unit;  
           [0043]    It is preferable that the liquid crystal display unit further includes a base plate on which the liquid crystal display panel is supported, the base plate is formed centrally with a window through which a display area of the liquid crystal display panel is exposed, and the base plate is formed with ribs for supporting the liquid crystal display panel, and a light-guide and a light-reflector both constituting the backlight unit.  
           [0044]    It is preferable that the base plate acts as a guide for the liquid crystal display unit to be slid into and out of the case.  
           [0045]    It is preferable that the opening is closed by bending a part of the case.  
           [0046]    It is preferable that the opening is closed by a cover composed of the same material as that of the case.  
           [0047]    It is preferable that the liquid crystal display panel, the first substrate, the second substrate, the backlight unit, the third substrate and the fourth substrate are stuck on the base plate.  
           [0048]    The advantages obtained by the aforementioned present invention will be described hereinbelow.  
           [0049]    In accordance with the present invention, a display device is simply slid into and out of a case through an opening formed with the case. Thus, it is no longer necessary to carry out steps of inverting parts or semi-products which steps were inevitably carried out in fabrication of the conventional liquid crystal display device, ensuring reduction in the number of fabrication steps.  
           [0050]    In addition, by mounting a liquid crystal display panel, a light-guide and a light-reflector on a base plate, it would be possible to reduce the number of parts in comparison with the conventional liquid crystal display device in which a holder plate is necessary for each of assembly units.  
           [0051]    The above and other objects and advantageous features of the present invention will be made apparent from the following description made with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0052]    FIGS.  1  to  10  are perspective views of a conventional liquid crystal display device, illustrating respective steps in fabrication of the same.  
         [0053]    FIGS.  11  to  17  are perspective views of a liquid crystal display device in accordance with an embodiment of the present invention, illustrating respective steps in fabrication of the same.  
         [0054]    [0054]FIG. 18 is a cross-sectional view taken along the line  18 - 18  in FIG. 16.  
         [0055]    [0055]FIG. 19 is a cross-sectional view taken along the line  19 - 19  in FIG. 16.  
         [0056]    FIGS.  20  to  22  are perspective views of a liquid crystal display device in accordance with an embodiment of the present invention, illustrating respective steps in fabrication of the same.  
         [0057]    [0057]FIG. 23 is a cross-sectional view taken along the line  23 - 23  in FIG. 22.  
         [0058]    [0058]FIG. 24 is a cross-sectional view taken along the line  24 - 24  in FIG. 22.  
         [0059]    [0059]FIG. 25 is a cross-sectional view taken along the line  24 - 24  in FIG. 22, illustrating different state of a liquid crystal display device from a state illustrated in FIG. 24.  
         [0060]    [0060]FIG. 26 is a cross-sectional view taken along the line  26 - 26  in FIG. 22.  
         [0061]    [0061]FIG. 27 is a rear view of an display apparatus including the liquid crystal display device in accordance with an embodiment of the present invention.  
         [0062]    [0062]FIG. 28 is a front view of the liquid crystal display device in accordance with an embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0063]    FIGS.  11  to  17  and  20  to  22  are perspective views of a liquid crystal display device in accordance with an embodiment of the present invention, illustrating respective steps in fabrication of the same, and FIGS. 18, 19 and  23  to  26  are cross-sectional views of the liquid crystal display device.  
         [0064]    [0064]FIG. 11 illustrates a frame-shaped base plate  100  as a part of the liquid crystal display device. The base plate  100  is composed of plastic resin or metal, and is centrally formed with a rectangular opening  110  through which a display area of the liquid crystal display device can be seen. The base plate  100  is formed with ribs  121 ,  122 ,  131 ,  132  and  133  for positioning and supporting other parts.  
         [0065]    Hereinbelow is explained a fabrication process of the liquid crystal display device with reference to FIGS.  12  to  20 .  
         [0066]    As illustrated in FIG. 12, a resilient and/or adhesive strip  140  is arranged along the rectangular opening  110  of the base plate  100 .  
         [0067]    As illustrated in FIG. 13, the panel unit including the liquid crystal display panel  200 , the signal-processing substrate  400  and the connection substrate  500  both of which are mechanically and electrically connected to the liquid crystal display panel  200  through the flexible substrates  300  is mounted on the base plate  100  with the strip  140  being sandwiched therebetween such that a display area of the liquid crystal display panel  200  can be seen through the opening  110  from a rear of the base plate  100 . The strip  140  absorbs deformation of the base plate  100  to ensure close contact between the liquid crystal display panel  200  and the base plate  100 .  
         [0068]    The liquid crystal display panel  200  is partially supported by the ribs  121  and  122  such that a display screen of the liquid crystal display panel  200  is kept horizontal.  
         [0069]    Since the connector substrates  500  are connected to the liquid crystal display panel  200  through the flexible substrates  300 , when the connector substrates  500  make contact with the ribs  133 , the flexible substrates  300  are made bent, and the connector substrates  500  slide on chamfered rounded tops of the ribs  133  into a gap formed between the ribs  131  and  133 . As a result, the connector substrates  500  are kept perpendicular relative to a display plane of the liquid crystal display device, as illustrated in FIG. 14.  
         [0070]    The liquid crystal display panel  200  is partially supported by the ribs  121  and  122  of the base plate  100  horizontally of a display plane of the liquid crystal display device. Then, a spacer  11  for positioning an optical sheet  12 , an optical sheet  12  and the light-guide  13  are mounted in this order on the liquid crystal display panel  200 .  
         [0071]    Specifically, a plastic spacer  11  having a thickness of about 0.2 to 1.5 mm and a width of about 1.0 to 5.0 mm is fixed onto a rear of the liquid crystal display panel  200  mounted on the base plate  100 . For instance, an adhesive is applied to a surface of the spacer  11 , and then, the spacer  11  is adhered to a rear surface of the liquid crystal display panel  200 . Then, the optical sheets  12  such as a lens sheet for collecting light, and a light-diffusion sheet for diffusing light are mounted in the spacer  11  adhered onto a rear surface of the liquid crystal display panel  200 . Then, the light-guide  13  is arranged on the spacer  11 . Between the liquid crystal display panel  200  and the light-guide  13  is formed a clearance equal to a thickness of the spacer  11 . The optical sheets  12  are mounted within the clearance.  
         [0072]    The ribs  132  are designed to have a distal end formed as a L-shaped hook for supporting the liquid crystal display panel  200 , the light-guide  13 , and the light-reflection sheet  14  all mounted on the base plate  100 . The ribs  132  vertically support the liquid crystal display panel  200 , the light-guide  13  and the light-reflection sheet  14  with the distal ends formed as a L-shaped hook, and horizontally support them with sidewalls thereof. The ribs  132  have a tapered outer sidewall, as illustrated in FIGS. 14 and 15.  
         [0073]    The cold cathode lamps  15  and the light-reflectors  16  for reflecting or collecting light to a desired direction are attached to opposite edges of the light-guide  13 . The light-reflectors  16  are composed of metal or plastic. The light-reflectors  16  in which the lamps  15  are arranged are U-shaped, and are open to the edges of the light-guide  13 .  
         [0074]    Lights emitted from the lamps  15  and reflected from the light-reflectors  16  are introduced entirely into and diffused in the light-guide  13 . As a result, the light-guide  13  act as a surface light source for the liquid crystal display panel  200 .  
         [0075]    The light-reflection sheet  14  is attached to a rear surface of the light-guide  13  for reflecting light back to the light-guide  13 . The light-reflection sheet  14  makes close contact with a surface of the light-guide  13 .  
         [0076]    The light-guide  13  is supported horizontally relative to a display plane of the liquid crystal display panel  200  by the ribs  131  of the base plate  100 .  
         [0077]    As illustrated in FIG. 15, the light-reflectors  16  are partially supported by the ribs  121  and  122 .  
         [0078]    After the light-reflection sheet  14  has been attached to the light-guide  13 , the signal-processing substrates  400  of the panel unit are mounted on a rear surface of the light-reflection sheet  14  by bending the flexible substrates  300 , as illustrated in FIG. 16.  
         [0079]    Then, as illustrated in FIG. 17, a conversion substrate  600  which receives external signals, converts the thus received signals into a desired form, and transmits the converted signals to the signal-processing substrate  400 , and an inverter substrate  700  which supplies a desired voltage to the lamps  15  are mounted on a rear surface of the light-reflection sheet  14 .  
         [0080]    [0080]FIG. 18 is a cross-sectional view taken along the line  18 - 18  in FIG. 16, illustrating that the liquid crystal display panel  200  and the light-reflector  16  are supported by the ribs  121  of the base plate  100 .  
         [0081]    [0081]FIG. 19 is a cross-sectional view taken along the line  19 - 19  in FIG. 16, illustrating that the light-guide  13  and the light-reflection sheet  14  are supported horizontally relative to a display plane  17  of the liquid crystal display panel  200  by the ribs  131  extending upwardly from the base plate  100 . As mentioned earlier, the connector substrates  500  are mounted perpendicularly to the display plane  17  of the liquid crystal display panel  200  in a gap formed between the ribs  131  and  133 .  
         [0082]    As illustrated in FIG. 16, the signal-processing substrates  400  are mounted on a rear surface of the light-reflection sheet  14  by bending the flexible substrates  300 , in which case, the flexible substrates  300  are bent so as to partially surround the optical sheets  12 , the light-guide  13 , the lamp  15  and the light-reflector  16 .  
         [0083]    On a rear surface of the light-reflection sheet  14  are mounted the conversion substrate  600  and the inverter substrate  700 . The conversion substrate  600  and the inverter substrate  700  are electrically connected to the signal-processing substrate  400  through cables  18 , as illustrated in FIGS. 17 and 20. The conversion substrate  600  and the inverter substrate  700  are fixed onto the light-reflection sheet  14  through double-sided adhesive tape having high cushion.  
         [0084]    [0084]FIG. 21 illustrates that a display unit, that is, the base plate  100  on which the above-mentioned various units are mounted is slid into a case  800  through an opening  801  formed at a side of the case  800 . FIG. 22 illustrates that the opening  801  of the case  800  is covered with a cover  820 . FIG. 23 is a cross-sectional view taken along the line  23 - 23  in FIG. 22, illustrating that the display unit is put in the case  800 .  
         [0085]    As illustrated in FIG. 23, the case  800  is formed at an inner surface of a sidewall thereof with a guide  810  by which the display unit is appropriately positioned and along which the display unit is slide into the case  800  through the opening  801 . After the display unit is slid into the case  800 , the guide  810  supports the display unit in the case  800 .  
         [0086]    [0086]FIG. 24 is a cross-sectional view taken along the line  24 - 24  in FIG. 22, illustrating that the display unit is slid into the case  800  through the opening  801 .  
         [0087]    The rib  132  is designed to have a reverse-L-shaped distal end acting as a hook for supporting the light-guide  13  or both of the light-guide  13  and the light-reflection sheet  14  making close contact with a rear surface of the light-guide  13 . The rib  132  supports the light-guide  13  and the light-reflection sheet  14  with its L-shaped distal end in a vertical direction, and has a tapered wall at which the rib  132  makes contact with the cover  820 .  
         [0088]    [0088]FIG. 25 is a cross-sectional view taken along the line  24 - 24  in FIG. 22, illustrating that the opening  801  is closed with the cover  820  after the display unit has been slid into the case  800  through the opening  801 .  
         [0089]    [0089]FIG. 26 illustrates an example of fastening the cover  820  to the case  800 . For instance, as illustrated in FIG. 26, the cover  820  may be fixed to the case  800  in the vicinity of the opening  801  by means of screws  45 .  
         [0090]    As illustrated in FIGS. 24 and 25, the cover  820  is formed as a part of the case  800 . The cover  820  is designed to be able to rotate about a bending center  830  for closing and opening the opening  801  of the case  800 . The bending center  830  is formed thinner than the rest of the case  800  for facilitating rotation of the cover  820 .  
         [0091]    The cover  820  engages to the rib  132 . When the opening  801  of the case  800  is closed with the cover  820 , the cover  820  makes contact with the rib  132 , and then, compresses the rib  132 . As a result, the rib  132  is deformed due to a compressive force exerted by the cover  820 , ensuring that the rib  132  firmly supports the light-guide  13 .  
         [0092]    The cover  820  is designed to have an inner surface at which the cover  820  makes contact with the rib  132 , identical to an outer shape of the rib  132 . As illustrated in FIG. 25, when the cover  820  is closed, the cover  820  surrounds the L-shaped distal end of the rib  132  to enhance a strength of the L-shaped distal end of the rib  132  as a hook.  
         [0093]    As illustrated in FIGS. 22 and 26, the cover  820  is fixed to the case  800  by the screws  45 , in which case, the L-shaped distal end of the rib  132  may be fixed in position also by the screws  45 .  
         [0094]    The rib  132  makes contact at the tapered sidewall thereof with the cover  820 . Due to a compressive force exerted by the cover  820 , the rib  132  is deformed, and hence, the L-shaped distal end of the rib  132  firmly compresses the light-guide  13  and the light-reflection sheet  14 . As illustrated in FIG. 26, the cover  820  is formed with through-holes  46  through which the screws  45  are inserted. The L-shaped distal end of the rib  132  is fixed to the case  800  by the screws  45 , which ensures that the L-shaped distal end of the rib.  132  more firmly compresses the light-guide  13  and the light-reflection sheet  14 .  
         [0095]    The liquid crystal display device having been assembled in the above-mentioned way is further assembled into a display apparatus  1  illustrated in FIGS. 27 and 28 wherein FIG. 27 is a rear view and FIG. 28 is a front view. The display apparatus  1  is supported with a stand  2 . An AC adapter  3  or a voltage transformer for feeding power to the display apparatus  1  is electrically connected to the display apparatus  1 , and an image-signal transmitter  4  is electrically connected to the display apparatus  1  through a cable  5 .  
         [0096]    For instance, the image-signal transmitter  4  is comprised of a personal computer. Image-signals transmitted from the image-signal transmitter  4  are input into the conversion substrate  600  in the display apparatus  1  through the cable  5 . A voltage transformed from a domestic voltage by the AC adapter  3  is input into the conversion substrate  600 . The conversion substrate  600  converts the thus received image-signals into drive signals, and further, the received voltage into a voltage suitable for driving the inverter substrate  700 . The inverter substrate  700  drives the lamps  15  for making a surface light source in the light-guide  13 .  
         [0097]    The conversion substrate  600  supplies desired voltage and signals to the signal-processing substrate  400 , which then supplies desired voltage and signals to the driver ICs to thereby drive the liquid crystal display panel  200  in the display apparatus  1 .  
         [0098]    In the above-mentioned embodiment, a liquid crystal display device is selected as an example of a display device. The present invention may be applied to other planar displays such as an organic electroluminescence (EL) display.  
         [0099]    While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by way of the present invention is not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims.  
         [0100]    The entire disclosure of Japanese Patent Application No. 2002-240174 filed on Aug. 21, 2002 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.

Technology Classification (CPC): 6