Patent Publication Number: US-2012040723-A1

Title: Electronic device and outer panel for electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2010-181583, filed on Aug. 16, 2010, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiment discussed herein is related to a technical field of an electronic device, such as a mobile phone, and an outer panel of the electronic device. 
     BACKGROUND 
     Electronic devices like mobile phones have a display unit, such as a liquid crystal display or an organic electro-luminescence (EL) display. Japanese laid-open patent publication No. 2008-83263 and Japanese laid-open patent publication No. 2009-8703 disclose methods for ensuring the water-tightness of a mobile phone by covering the body of a mobile phone including the display unit with a single outer panel. 
     SUMMARY 
     According to an aspect of an embodiment, an electronic device includes a display unit, a protective member disposed on the display unit to protect the display unit, a surface member disposed on the same plane as the protective member and a waterproof sheet covering at least a gap between the protective member and the surface member, the waterproof sheet is disposed between the display unit and the protective and surface members. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating the exterior of a front-side part of a mobile phone according to this embodiment in an open state. 
         FIG. 2  is a perspective view illustrating the exterior of a rear-side part of the mobile phone according to this embodiment in an open state. 
         FIG. 3A  is a side view, and  FIGS. 3B and 3C  are perspective views illustrating the exterior of the mobile phone according to this embodiment in a closed state. 
         FIGS. 4A and 4B  are perspective views illustrating a detailed configuration of a display unit. 
         FIG. 5A  is an exploded perspective view and  FIG. 5B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of a front-side part of the display unit, in which respective components of the front-side part are illustrated in an exploded manner. 
         FIG. 6A  is an exploded perspective view and  FIG. 6B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of a rear-side part of the display unit, in which respective components of the rear-side part are illustrated in an exploded manner. 
         FIG. 7A  is an exploded perspective view and  FIG. 7B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of a front-side part according to a first modification, in which respective components of the front-side part are illustrated in an exploded manner. 
         FIG. 8A  is an exploded perspective view and  FIG. 8B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of a rear-side part according to the first modification, in which respective components of the rear-side part are illustrated in an exploded manner. 
         FIG. 9A  is an exploded perspective view and  FIG. 9B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of a front-side part according to a second modification, in which respective components of the front-side part are illustrated in an exploded manner. 
         FIG. 10A  is an exploded perspective view and  FIG. 10B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of a rear-side part according to the second modification, in which respective components of the rear-side part are illustrated in an exploded manner. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the body of a mobile phone including a display unit, when an outer panel including a panel portion for covering the display unit and a panel portion for covering a portion other than the display unit is used to improve the flexibility of decorating the mobile phone, the two panel portions may have different thicknesses due to difference in specification between the two panel portions. In addition, the shape of a casing frame that receives the outer panel including these panel portions becomes complex. Thus, sink marks may occur while forming the outer panel or the casing frame. Such sink marks make it difficult to maintain water-tightness between the outer panel and the casing frame. 
     An exemplary method for overcoming this problem is that the outer panel is divided, as separate components, into a panel portion for covering the display unit and a panel portion for covering a portion other than the display unit. However, because one outer panel is divided into a plurality of panel portions, it is difficult to maintain water-tightness at the boundary of the divided panel portions. 
     This situation occurs not only in mobile phones, but also in any electronic device having a display unit. 
     Embodiments of the present invention will be described below with reference to the drawings. In the following description, a mobile phone, which is an example of the electronic device, will be described. However, the configuration described below may be applied not only to mobile phones, but also to other various electronic devices (for example, PDAs, mini-personal computers, notebook personal computers, and desktop personal computers). 
     1. Exterior of Mobile Phone 
     Referring to  FIGS. 1 to 3C , the exterior of a mobile phone  1  according to this embodiment will be described.  FIG. 1  is a perspective view illustrating the exterior of a front-side part of a mobile phone  1  according to this embodiment in an open state.  FIG. 2  is a perspective view illustrating the exterior of a rear-side part of the mobile phone  1  according to this embodiment in an open state.  FIG. 3A  is a side view, and  FIGS. 3B and 3C  are perspective views illustrating the exterior of the mobile phone  1  according to this embodiment in a closed state. 
     Although the mobile phone  1  of a foldable type will be described below, the configuration described below may be applied to mobile phones having other shapes (for example, straight mobile phones or slidable mobile phones).  FIGS. 1 to 3C  selectively illustrate the configurations necessary for the description of the mobile phone  1  according to this embodiment. Thus, the mobile phone  1  according to this embodiment may include other configurations (not illustrated) that are necessary for a mobile phone. 
     As illustrated in  FIGS. 1 and 2 , the mobile phone  1  includes a display unit  10  and an operation unit  20 . Note that  FIGS. 1 and 2  illustrate the mobile phone  1  in an unfolded state (i.e., in an open state). 
     As illustrated in  FIG. 1 , the display unit  10  includes a main display  11  and an ear piece  14  on the front side (inner side) thereof. The main display  11  is an example of the “display unit” and indicates information (for example, characters, images, and patterns). For example, the main display  11  indicates the current time, the charging status of the mobile phone  1 , the signal strength of the mobile phone  1 , the record of incoming and outgoing calls, the address book, and e-mail messages. For example, the main display  11  is a liquid crystal display or an organic EL display. The ear piece  14  has a speaker  14   a  therein. A user of the mobile phone  1  may hear audio output from the speaker  14   a.    
     Similarly, as illustrated in  FIG. 1 , the operation unit  20  has a plurality of operation buttons  21  and a mouth piece  22  on the front side thereof. A user operates the operation buttons  21  including, for example, number buttons, a power button, a talk button, a mail button, and a cross-bar button. The mouth piece  22  has a microphone  22   a  therein. A user of the mobile phone  1  inputs audio into the mobile phone  1  through the microphone  22   a.    
     On the other side, as illustrated in  FIG. 2 , the display unit  10  includes a sub-display  15  and an electrostatic sensor  16  on the rear side (outer side) thereof. The sub-display  15  is an example of the “display unit” and indicates information (for example, characters, images, and patterns). For example, the sub-display  15  indicates the current time, the charging status of the mobile phone  1 , and the signal strength of the mobile phone  1 . For example, the sub-display  15  is a liquid crystal display or an organic EL display. The electrostatic sensor  16  detects an operation by a user sweeping across the rear surface of the display unit  10  where the electrostatic sensor  16  is disposed and outputs a signal according to the operation. The electrostatic sensor  16  may be covered by a plastic panel  122  (see  FIGS. 6A and 6B , described below), and thus, it does not have to be exposed outside the display unit  10 . 
     Similarly, as illustrated in  FIG. 2 , the operation unit  20  includes a camera  23  for capturing, for example, images and movies, a rechargeable battery (not illustrated), a battery lid  24  covering the rechargeable battery, metal charging terminals  25  for charging the rechargeable battery, etc., on the rear side thereof. 
     As illustrated in  FIGS. 1 and 2 , the mobile phone  1  according to this embodiment is a foldable mobile phone that may be folded in such a manner that the display unit  10  is brought toward the operation unit  20  in the direction indicated by the dual arrow. As a result, as illustrated in  FIG. 3A , the mobile phone  1  is folded in such a manner that the main display  11  of the display unit  10  faces the operation buttons  21  of the operation unit  20  (i.e., a closed state). 
     As illustrated in  FIG. 3B , the rear surface of the display unit  10  (i.e., the sub-display  15  and the electrostatic sensor  16 ) of the closed mobile phone  1  may be disposed outside, and the front surface of the display unit  10  (i.e., the main display  11  and the ear piece  14 ) of the closed mobile phone  1  does not have to be exposed outside. Note that, however, the rear surface of the display unit  10  of the closed mobile phone  1  does not have to be exposed outside, and the front surface thereof may be exposed outside. 
     Similarly, as illustrated in  FIG. 3C , the rear surface of the operation unit  20  (i.e., the camera  23 , the battery lid  24 , and the charging terminals  25 ) of the closed mobile phone  1  may be exposed outside, and the front surface of the operation unit  20  (i.e., the operation buttons  21  and the mouth piece  22 ) of the closed mobile phone  1  does not have to be exposed outside. Note that, however, the rear surface of the operation unit  20  of the closed mobile phone  1  does not have to be exposed outside, and the front surface thereof may be exposed outside. 
     2. Configuration of Display Unit 
     Referring to  FIGS. 4A and 4B , a detailed configuration of the display unit  10  will be described.  FIGS. 4A and 4B  are perspective views illustrating a detailed configuration of the display unit  10 . 
     As illustrated in  FIGS. 4A and 4B , the display unit  10  includes a front-side part  110  having front-side components (i.e., the main display  11  and the ear piece  14 ), and a rear-side part  120  having rear-side components (i.e., the sub-display  15  and the electrostatic sensor  16 ).  FIG. 4A  illustrates the display unit  10  as viewed from the front-side part  110 , and  FIG. 4B  illustrates the display unit  10  as viewed from the rear-side part  120 . 
     The front-side part  110  and the rear-side part  120  are fixed or bonded to each other with, for example, a predetermined bonding member (e.g., an adhesive or a screw). At this point, as illustrated in  FIGS. 4A and 4B , the front-side part  110  and the rear-side part  120  are fixed or bonded to each other such that the surfaces thereof opposite to the surfaces having the main display  11  or the sub-display  15  face each other. In other words, as illustrated in  FIGS. 4A and 4B , the front-side part  110  and the rear-side part  120  are fixed or bonded to each other such that the main display  11  and the sub-display  15  may be viewed from the outside. 
     3. Configuration of Front-Side Part of Display Unit 
     Referring to  FIGS. 5A and 5B , a detailed configuration of the front-side part  110  of the display unit  10  will be described.  FIG. 5A  is an exploded perspective view and  FIG. 5B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of the front-side part  110  of the display unit, in which respective components of the front-side part  110  are illustrated in an exploded manner. 
     As illustrated in  FIGS. 5A and 5B , the front-side part  110  includes a plastic panel  111 , a plastic panel  112 , a polyethylene terephthalate (PET) sheet  113 , the main display  11 , and a front frame (front casing)  115 .  FIG. 5B  illustrates a cross-sectional view taken along line V-V′ in  FIG. 5A . 
     The plastic panel  111  is an example of the protective member and is a plastic panel (or a thin plate) for protecting the main display  11 . The plastic panel  111  is disposed in the front-side part  110  so as to overlap the main display  11  in a direction normal to the plastic panel  111 . For example, the plastic panel  111  may be disposed such that a part or the entirety of the plastic panel  111  overlaps a part or the entirety of the main display  11 . The plastic panel  111  transmits light. 
     The plastic panel  112  is an example of the surface member and is disposed on the same plane as the plastic panel  111 . Preferably, the plastic panel  112  is disposed at a position not overlapping the main display  11  (or the plastic panel  111 ) in a direction normal to the plastic panel  112 . In the example illustrated in  FIGS. 5A and 5B , a configuration is employed in which the plastic panel  112  has a frame-like shape with an opening having a size equal to or larger than the main display  11  (or a size equal to or larger than the plastic panel  111 ) and in which the plastic panel  111  is fitted into the opening. Note that, in  FIGS. 5A and 5B , the plastic panel  112  is indicated with hatching, and a portion surrounded by the hatched plastic panel  112  is the opening. The plastic panel  112  may be disposed at a position overlapping a part of the main display  11  (or a part of the plastic panel  111 ) in a direction normal to the plastic panel  112 . Predetermined decoration may be applied to the surface or inside of the plastic panel  112 . Examples of such decoration include printing or engraving characters, numbers, or pictures, coloring with predetermined colors, and polishing. In addition, when a light emitting device, such as a light emitting diode (LED) is disposed between the plastic panel  112  and the front frame  115 , the plastic panel  112  may have a hole provided as predetermined decoration, through which light emitted from the light emitting device is transmitted outside. The plastic panel  112  may have either a light-transmitting property or a non-light-transmitting property. 
     Note that, not only plastic panels, but also panels made of other materials, such as metal, which meet the above-described conditions may be used as the plastic panels  111  and  112 . Furthermore, in addition to the plastic panels  111  and  112 , the front-side part  110  may include more plastic panels, according to the size, shape, and number of the main display  11 , the size, shape, and number of other functional portions, and the type, shape, and number of decoration to be applied. 
     The PET sheet  113  is an example of the waterproof sheet and is a film-like sheet containing PET. The PET sheet  113  transmits light. Note that a film-like sheet or a thin-plate-like panel containing a material other than PET (for example, an arbitrary resin, fiber, or metal) may be used as the PET sheet  113 . Predetermined decoration may be applied to the surface or inside of the PET sheet  113 . 
     The plastic panels  111  and  112  are bonded to one surface of the PET sheet  113  with an optically clear adhesive (OCA)  114 . However, the plastic panels  111  and  112  may be bonded to one surface of the PET sheet  113  with an optical adhesive (or a light-transmitting adhesive) other than the OCA  114 . The arrows in  FIGS. 5A and 5B  indicate attaching conditions of the plastic panels  111  and  112  to the PET sheet  113 . Accordingly, the PET sheet  113  is larger in size than the plastic panels  111  and  112  in a surface direction. However, as will be described in first and second modifications below, the PET sheet  113  may be smaller in size than the plastic panels  111  and  112  in a surface direction. Although  FIGS. 5A and 5B  illustrate an example in which the OCA  114  is applied over the entire surface of the PET sheet  113 , the OCA  114  may be applied between the PET sheet  113  and the plastic panel  111 , and between the PET sheet  113  and the plastic panel  112 . In other words, the OCA  114  does not have to be applied to a portion of the PET sheet  113  corresponding to the gap between the plastic panels  111  and  112 . 
     The other surface of the PET sheet  113  (i.e., the surface opposite to the surface to which the plastic panels  111  and  112  are attached) is attached to the front frame  115  with a double-faced adhesive tape (hereinafter referred to as a “double-faced tape”)  116 . However, the other surface of the PET sheet  113  may be attached to the front frame  115  with an arbitrary bonding member (e.g., an adhesive or a screw) other than the double-faced tape  116 . The PET sheet  113  has a size sufficient to sandwich the entire main display  11  with respect to the front frame  115 . In addition, the double-faced tape  116  for attaching the PET sheet  113  to the front frame  115  is preferably disposed on the front frame  115  (or the PET sheet  113 ) such that the entire main display  11  is positioned on the inner side of the double-faced tape  116 . Furthermore, the double-faced tape  116  is disposed so as to form a closed loop on the front frame  115  (or the PET sheet  113 ) so that the water-tightness of the main display  11  positioned on the inner side of the double-faced tape  116  may be ensured. 
     The PET sheet  113  to which the plastic panels  111  and  112  are attached is an example of the outer panel. 
     The front frame  115  is a frame (or a casing) that constitutes the exterior of the front-side part  110 . A surface of the front frame  115  opposite to the surface to which the main display  11  is mounted is attached to a rear frame  125 . Thus, the display unit  10  is formed. 
     4. Configuration of Rear-Side Part of Display Unit 
     Referring to  FIGS. 6A and 6B , a detailed configuration of the rear-side part  120  of the display unit  10  will be described.  FIG. 6A  is an exploded perspective view and  FIG. 6B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of the rear-side part  120  of the display unit  10 , in which respective components of the rear-side part  120  are illustrated in an exploded manner. 
     As illustrated in  FIGS. 6A and 6B , the rear-side part  120  includes a plastic panel  121 , a plastic panel  122 , a PET sheet  123 , the sub-display  15 , the electrostatic sensor  16 , and a rear frame (rear casing)  125 .  FIG. 6B  illustrates a cross-sectional view taken along line VI-VI′ in  FIG. 6A . 
     The plastic panel  121  is an example of the protective member and is a plastic panel (or a thin plate) for protecting the sub-display  15 . The plastic panel  121  is preferably disposed in the rear-side part  120  so as to overlap the sub-display  15  in a direction normal to the plastic panel  121 . For example, the plastic panel  121  may be disposed such that a part or the entirety of the plastic panel  121  overlaps a part or the entirety of the sub-display  15 . The plastic panel  121  transmits light. 
     The plastic panel  122  is an example of the surface member and is disposed on the same plane as the plastic panel  121 . The plastic panel  122  is disposed at a position not overlapping the sub-display  15  (or the plastic panel  121 ) in a direction normal to the plastic panel  122 . In the example illustrated in  FIGS. 6A and 6B , the plastic panel  122  is disposed adjacent to the plastic panel  121 . However, the plastic panel  122  may be disposed at a position overlapping a part of the sub-display  15  (or a part of the plastic panel  121 ) in a direction normal to the plastic panel  122 . The surface of the plastic panel  122  may be processed (for example, flattened to form an outer surface of a touch pad) to enable an operation using the electrostatic sensor  16 . Alternatively, other predetermined decoration may be applied to the surface or inside of the plastic panel  122 . Furthermore, when a light emitting device, such as an LED, is disposed between the plastic panel  122  and the rear frame  125 , the plastic panel  122  may have a hole provided as predetermined decoration, through which light emitted from the light emitting device is transmitted outside. The plastic panel  122  may have either a light-transmitting property or a non-light-transmitting property. 
     Note that, not only plastic panels, but also panels made of other materials, such as metal, which meet the above-described conditions may be used in place of the plastic panels  121  and  122 . Furthermore, in addition to the plastic panel  121  and the  122 , the rear-side part  120  may include more plastic panels according to the size, shape, and number of the sub-display  15 , the size, shape, and number of the electrostatic sensor  16 , the size, shape, and number of other functional portions, and the type, shape, and number of decoration to be applied. 
     The PET sheet  123  is an example of the waterproof sheet and is a film-like sheet containing PET. The PET sheet  123  transmits light. Note that a film-like sheet or a thin-plate-like panel containing a material other than PET (for example, an arbitrary resin, fiber, or metal) may be used as the PET sheet  123 . Predetermined decoration may be applied to the surface or inside of the PET sheet  123 . 
     The plastic panels  121  and  122  are bonded to one surface of the PET sheet  123  with an OCA  124 . However, the plastic panels  121  and  122  may be bonded to one surface of the PET sheet  123  with an optical adhesive (or a light-transmitting adhesive) other than the OCA  124 . The arrows in  FIGS. 6A and 6B  indicate attaching conditions of the plastic panels  121  and  122  to the PET sheet  123 . Accordingly, the PET sheet  123  is larger in size than the plastic panels  121  and  122  in a surface direction. However, as will be described in the first and second modifications below, the PET sheet  123  may be smaller in size than the plastic panels  121  and  122  in a surface direction. Although  FIGS. 6A and 6B  illustrate an example in which the OCA  124  is applied over the entire surface of the PET sheet  123 , the OCA  124  may be applied between the PET sheet  123  and the plastic panel  121 , and between the PET sheet  123  and the plastic panel  122 . In other words, the OCA  124  does not have to be applied to a portion of the PET sheet  123  corresponding to the gap between the plastic panels  121  and  122 . 
     The other surface of the PET sheet  123  (i.e., the surface opposite to the surface to which the plastic panels  121  and  122  are attached) is attached to the rear frame  125  with a double-faced tape  126 . However, the other surface of the PET sheet  123  may be attached to the rear frame  125  with an arbitrary bonding member (e.g., an adhesive or a screw) other than the double-faced tape  126 . The PET sheet  123  has a size sufficient to sandwich the entire sub-display  15  and electrostatic sensor  16  with respect to the rear frame  125 . In addition, the double-faced tape  126  for attaching the PET sheet  123  to the rear frame  125  is preferably disposed on the rear frame  125  (or the PET sheet  123 ) such that the entire sub-display  15  and electrostatic sensor  16  are positioned on the inner side of the double-faced tape  126 . Furthermore, the double-faced tape  126  is disposed so as to form a closed loop on the rear frame  125  (or the PET sheet  123 ) so that the water-tightness of the sub-display  15  and the electrostatic sensor  16  positioned on the inner side of the double-faced tape  126  may be ensured. 
     The PET sheet  123  to which the plastic panels  121  and  122  are attached is an example of the outer panel. 
     The rear frame  125  is a frame (or a casing) that constitutes the exterior of the rear-side part  120 . A surface of the rear frame  125  opposite to the surface to which the sub-display  15  and electrostatic sensor  16  are mounted is attached to the surface of the front frame  115  opposite to the surface to which the main display  11  is mounted. Thus, the display unit  10  is formed. 
     As has been described above, in the mobile phone  1  according to this embodiment, two independent plastic panels  111  and  112  serve as outer panels on the front-side part  110 . Therefore, compared with the case where one outer panel having the same function as the plastic panels  111  and  112  is used, the flexibility of decorating the mobile phone  1  may be improved. That is, the plastic panel  111  for covering the main display  11  is formed of a transparent material using a method suitable for that material, almost or completely without taking into consideration the specification or properties required for the plastic panel  112 . Similarly, the plastic panel  112  is made of a material that may be easily decorated using a method suitable for that material, almost or completely without taking into consideration the specification or properties required for the plastic panel  111 . The same technical advantages may also be obtained in the two independent plastic panels  121  and  122  of the rear-side part  120 . 
     Furthermore, in the mobile phone  1  according to this embodiment, the plastic panels  111  and  112  may be separately fabricated (for example, the plastic panels  111  and  112  may be separately designed and formed). Therefore, sink marks occurring when one outer panel having the same function as the plastic panels  111  and  112  is fabricated may be appropriately suppressed. The same technical advantages may also be obtained in the two independent plastic panels  121  and  122  of the rear-side part  120 . 
     Furthermore, in the mobile phone  1  according to this embodiment, more plastic panels may be disposed in addition to the plastic panels  111  and  112 . That is, an arbitrary or desired number of plastic panels may be attached to the PET sheet  113 . This enables the mobile phone  1  to be decorated individually for each user and enables the mobile phone  1  to be easily customized. 
     Furthermore, in the mobile phone  1  according to this embodiment, the plastic panels  111  and  112  do not need to be stacked on top of each other in the thickness direction of the plastic panels  111  and  112 . In other words, the plastic panels  111  and  112  do not need to be stacked on top of each other in the thickness direction of the mobile phone  1 . Thus, the thickness of the mobile phone  1  may be reduced. 
     In the mobile phone  1  according to this embodiment, the gap between the plastic panels  111  and  112  is covered by the PET sheet  113 . Accordingly, the PET sheet  113  prevents water droplets flowing along the gap between the plastic panels  111  and  112  from entering the inside of the front-side part  110 . Thus, the water-tightness of the mobile phone  1  may be ensured. The same technical advantages may also be obtained in the PET sheet  123  of the rear-side part  120 . 
     In the mobile phone  1  according to this embodiment, the plastic panels  111  and  112  are bonded to the PET sheet  113  with the OCA  114 . Thus, degradation of the optical properties (for example, attenuation or the like of light emitted from the main display  11 ) due to the bonding member used for bonding the plastic panels  111  and  112  to the PET sheet  113  may be suppressed. Accordingly, the user may clearly view the content of indication on the main display  11 . The same technical advantages may also be obtained even in the case where the plastic panels  111  and  112  are bonded to the PET sheet  113  with an optical adhesive other than the OCA  114 . The same technical advantages may also be obtained in the OCA  124  of the rear-side part  120 . 
     Furthermore, if the plastic panel  111  transmits light, degradation of the optical properties may be further suppressed. Similarly, if the PET sheet  113  transmits light, degradation of the optical properties may be further suppressed. Accordingly, a user may more clearly view the content of indication on the main display  11 . Thus, with the mobile phone  1  according to this embodiment, the display unit  10  that transmits light from the entire surface thereof while ensuring the water-tightness may be achieved. The same technical advantages may also be obtained in the rear-side part  120 . 
     With the mobile phone  1  according to this embodiment, the PET sheet  113  may be decorated. Therefore, variety of decoration for the mobile phone  1  may be further increased. 
     As has been described, the plastic panel  111  and the PET sheet  113  both transmit light. Thus, the plastic panel  111  and the PET sheet  113  may be integrally formed. Then, by bonding the plastic panel  112  to the integrally formed plastic panel  111  and PET sheet  113  with the OCA  114 , a front-side part like the above-described front-side part  110  is fabricated. Similarly, the plastic panel  121  and the PET sheet  123  may be integrally formed. Then, by bonding the plastic panel  122  to the integrally formed plastic panel  121  and PET sheet  123  with the OCA  124 , a rear-side part like the above-described rear-side part  120  is fabricated. Accordingly, the technical advantages as described above may also be appropriately enjoyed with this configuration. 
     5. First Modification 
     Referring to  FIGS. 7A ,  7 B,  8 A and  8 B, a mobile phone according to a first modification will be described. The mobile phone according to the first modification is different from the above-described mobile phone  1  in configurations of a front-side part  110   a  and a rear-side part  120   a.  Accordingly, to simplify the description, the following description will be given focusing on the front-side part  110   a  and rear-side part  120   a  according to the first modification, and the configuration and operation that are the same as those of the mobile phone  1  will be denoted by the same reference numerals, and a detailed description thereof will be omitted.  FIG. 7A  is an exploded perspective view and  FIG. 7B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of the front-side part  110   a  according to the first modification, in which respective components of the front-side part  110   a  are illustrated in an exploded manner.  FIG. 8A  is an exploded perspective view and  FIG. 8B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of the rear-side part  120   a  according to the first modification, in which respective components of the rear-side part  120   a  are illustrated in an exploded manner. 
     As illustrated in  FIGS. 7A and 7B , similarly to the above-described front-side part  110 , the front-side part  110   a  according to the first modification includes the plastic panel  111 , the plastic panel  112 , a PET sheet  113   a,  the main display  11 , and the front frame  115 .  FIG. 7B  illustrates a cross-sectional view taken along line VII-VII′ in  FIG. 7A . 
     In the first modification, the shape of the PET sheet  113   a  is different from that of the above-described PET sheet  113 . More specifically, the PET sheet  113   a  is shaped to cover a gap between the plastic panels  111  and  112 . In other words, the PET sheet  113   a  does not need to cover a portion other than the gap between the plastic panels  111  and  112 . Thus, the PET sheet  113   a  has a frame-like shape with an opening  117   a.    
     Note that, in the first modification, each of the plastic panel  111 , the plastic panel  112 , and the PET sheet  113   a  may be attached to the front frame  115  with the double-faced tape  116 . That is, in the first modification, the water-tightness of a space defined by the plastic panel  111 , the plastic panel  112 , the PET sheet  113   a,  the double-faced tape  116 , and the front frame  115  may be ensured. Accordingly, in the first modification, the main display  11  may be disposed in the space defined by the plastic panel  111 , the plastic panel  112 , the PET sheet  113   a,  the double-faced tape  116 , and the front frame  115 . 
     As illustrated in  FIGS. 8A and 8B , similarly to the rear-side part  120 , the rear-side part  120   a  according to the first modification includes the plastic panel  121 , the plastic panel  122 , a PET sheet  123   a,  the sub-display  15 , the electrostatic sensor  16 , and the rear frame  125 .  FIG. 8B  illustrates a cross-sectional view taken along line VIII-VIII′ in  FIG. 8A . 
     In the first modification, the shape of the PET sheet  123   a  is different from that of the above-described PET sheet  123 . More specifically, the PET sheet  123   a  is shaped so as to cover a gap between the plastic panels  121  and  122 . In other words, the PET sheet  123   a  does not need to cover a portion other than the gap between the plastic panels  121  and  122 . 
     Note that, in the first modification, each of the plastic panel  121 , the plastic panel  122 , and the PET sheet  123   a  is attached with the OCA  124 , and the PET sheet  123   a  is attached to the rear frame  125  with the double-faced tape  126 . That is, in the first modification, the water-tightness of a space defined by the plastic panel  121 , the plastic panel  122 , and the PET sheet  123   a,  the double-faced tape  126 , and the rear frame  125  is ensured. Accordingly, in the first modification, the sub-display  15  and the electrostatic sensor  16  are disposed in the space defined by the plastic panel  121 , the plastic panel  122 , the PET sheet  123   a,  the double-faced tape  126 , and the rear frame  125 . 
     As has been described above, similarly to the mobile phone  1  above, in the first modification too, the gap between the plastic panels  111  and  112  is covered by the PET sheet  113   a.  Accordingly, the PET sheet  113   a  prevents water droplets flowing along the gap between the plastic panels  111  and  112  from entering the inside of the front-side part  110   a.  Thus, the water-tightness of the mobile phone  1  may be ensured. The same technical advantages may also be obtained in the PET sheet  123   a  of the rear-side part  120   a.    
     The mobile phone according to the first modification may of course appropriately enjoy other technical advantages enjoyed by the mobile phone  1 . 
     6. Second Modification 
     Referring to  FIGS. 9A ,  9 B,  10 A and  10 B, a mobile phone according to a second modification will be described. The mobile phone according to the second modification is different from the above-described mobile phone  1  in configurations of a front-side part  110   b  and a rear-side part  120   b.  Accordingly, to simplify the description, the following description will be given focusing on the front-side part  110   b  and rear-side part  120   b  according to the second modification, and the configuration and operation that are the same as those of the mobile phone  1  will be denoted by the same reference numerals, and a detailed description thereof will be omitted.  FIG. 9A  is an exploded perspective view and  FIG. 9B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of the front-side part  110   b  according to the second modification, in which respective components of the front-side part  110   b  are illustrated in an exploded manner.  FIG. 10A  is an exploded perspective view and  FIG. 10B  is an exploded cross-sectional view, respectively, illustrating a detailed configuration of the rear-side part  120   b  according to the second modification, in which respective components of the rear-side part  120   b  are illustrated in an exploded manner. 
     As illustrated in  FIGS. 9A and 9B , similarly to the above-described front-side part  110 , the front-side part  110   b  according to the second modification includes the plastic panel  111 , the plastic panel  112 , a PET sheet  113   b,  the main display  11 , and the front frame  115 .  FIG. 9B  illustrates a cross-sectional view taken along line IX- IX′ in  FIG. 9A . 
     In the second modification, the shape of the PET sheet  113   b  is different from those of the above-described PET sheet  113  and PET sheet  113   a.  More specifically, the PET sheet  113   b  is shaped to cover a gap between the plastic panels  111  and  112 , as well as the outer edges of the plastic panels  111  and  112 . In other words, the PET sheet  113   b  does not need to cover a portion other than the gap between the plastic panels  111  and  112 , as well as the outer edges of the plastic panels  111  and  112 . Thus, the PET sheet  113   b  has a frame-like shape with an opening  117   b.    
     As illustrated in  FIGS. 10A and 10B , similarly to the rear-side part  120 , the rear-side part  120   b  according to the second modification includes the plastic panel  121 , the plastic panel  122 , a PET sheet  123   b,  the sub-display  15 , the electrostatic sensor  16 , and the rear frame  125 .  FIG. 10B  illustrates a cross-sectional view taken along line X-X′ in  FIG. 10A . 
     In the second modification, the shape of the PET sheet  123   b  is different from those of the above-described PET sheet  123  and PET sheet  123   a.  More specifically, the PET sheet  123   b  is shaped to cover a gap between the plastic panels  121  and  122 , as well as the outer edges of the plastic panels  121  and  122 . In other words, the PET sheet  123   b  does not need to cover a portion other than the gap between the plastic panels  121  and  122 , and the outer edges of the plastic panels  121  and  122 . Thus, the PET sheet  123   b  has a frame-like shape with openings  127   b.    
     As has been described above, similarly to the mobile phone  1  above, in the second modification too, the gap between the plastic panels  111  and  112  is covered by the PET sheet  113   b.  Accordingly, the PET sheet  113   b  prevents water droplets flowing along the gap between the plastic panels  111  and  112  from entering the inside of the front-side part  110   b.  Thus, the water-tightness of the mobile phone  1  may be ensured. The same technical advantages may also be obtained in the PET sheet  123   b  of the rear-side part  120   b.    
     The mobile phone according to the second modification may of course appropriately enjoy other technical advantages enjoyed by the mobile phone  1 . 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a illustrating of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.