Abstract:
A portable display device having improved durability includes: a mold frame mounting a first display panel and a back light assembly thereon; at least one printed circuit board, arranged on one surface of the mold frame, to supply control signals to the first display panel; and a protruding portion, surrounding and wrapping at least two sides of the at least one printed circuit board, and extending from at least two side surfaces of the mold frame, the at least two side surfaces of the mold frame being connected together.

Description:
CLAIM OF PRIORITY  
       [0001]     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from an application for PORTABLE DISPLAY DEVICE earlier filed in the Korean Intellectual Property Office on the 23 rd  of Nov. 2005 and there duly assigned Serial No. 10-2005-0112569.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a portable display device, and more particularly to a portable display device having improved durability with a transformed mold frame.  
         [0004]     2. Description of the Related Art  
         [0005]     Recently, several kinds of flat display devices have been developed, in which the weak points of Cathode Ray Tubes (CRTs), that is, the weight and the volume, have been reduced. Such flat display devices include Liquid Crystal Displays (LCDs), Field Emission Displays (FEDs), Plasma Display Panels (PDPs), and Light Emitting Displays, etc.  
         [0006]     Liquid Crystal Displays are smaller and lighter and have a low power consumption, and are considered to be an alternative to overcome the weak points of CRTs. At present, the Liquid Crystal Display is mounted on portable devices, such as cellular phones and PDAs (Portable Digital Assistants) and so on and on monitors and TVs.  
         [0007]      FIG. 1  is a schematic perspective view of a conventional portable display device. In  FIG. 1 , a dual display device, such as a cellular phone, includes at least one Liquid Crystal Display.  
         [0008]     The conventional portable display device  50  includes a first display panel  5 , a mold frame  10  receiving a back light assembly (not shown), etc., and at least one printed circuit board  20  mounted on a rear surface of a mold frame  10  and a second display panel  30  mounted on the printed circuit board  20 .  
         [0009]     The first display panel  5  is a Liquid Crystal Display panel having upper and lower substrates and having liquid crystal cells arranged in a matrix therebetween. A Thin Film Transistor (TFT) is included with each liquid crystal cell to shift video signals.  
         [0010]     An integrated circuit (not shown) is arranged on one side of the first display panel  5 , and data signals and scan signals are supplied from the integrated circuit. The first display panel  5  which received the data signals and scan signals, displays a picture image corresponding to the data signal and scan signal.  
         [0011]     The back light assembly supplies the light to display the constant picture image on the first display panel  5 . The back light assembly includes a light source (not shown). A mold frame  10  is included on the back light assembly, and the first display panel  5  and light source, etc., are fixed inside of the mold frame  10 . Alignment tips  10   a  are formed on the right angle edges of the mold frame  10  to guide the position of the printed circuit board  20 . The printed circuit board  20  receives drive signals from the drive circuit of the cellular phone (not shown).  
         [0012]     The printed circuit board  20  includes a cellular phone connector  22 . The cellular phone connector  22  interfaces with another connector which is coupled to the driving circuit of the cellular phone, and receives the driving signals from the driving circuit of the cellular phone.  
         [0013]     The printed circuit board  20  which receives the driving signals produces multiple control signals corresponding to the driving signals.  
         [0014]     The control signals produced in the printed circuit board  20  are supplied to the first display panel  5  and light source and so on, and provides the constant picture image on the first display panel  5   
         [0015]     Grooves corresponding to the alignment tips  10   a  on the mold frame  10  are formed on the printed circuit board  20 . The grooves on the printed circuit board  20  are formed on the rectangular edge of the printed circuit board  20  and the alignment tips  10   a  are projected about as high as the printed circuit board  20 .  
         [0016]     Likewise, if, the grooves on the printed circuit board  20  are located on the alignment tips  10   a , the printed circuit board  20  and the mold frame  10  can be attached in an array.  
         [0017]     The second display panel  30  is connected to the printed circuit board  20  on a rear surface of the printed circuit board  20  and displays a picture image. The second display panel  30  is either an Organic Light Emitting Display panel or a Liquid Crystal Display panel.  
         [0018]     In accordance with the trends of minimization and slimming of the portable device, the total thickness of the display device is decreasing and protection elements which are not used to drive the display device have been being removed, which cause slimming of the portable display device as whole. However, the slimming weakens the durability of the portable display device and causes frequent faults and destruction thereof. Accordingly, a structural method to improve the durability without increasing the thickness of the portable display device has been sought.  
       SUMMARY OF THE INVENTION  
       [0019]     Considering the above mentioned problem, an object of the present invention is to provide a portable display device having improved durability with a transformed mold frame.  
         [0020]     These and other objects of the present invention can be achieved by providing a portable display device including: a mold frame mounting a first display panel and a back light assembly thereon; at least one printed circuit board, arranged on one surface of the mold frame, to supply control signals to the first display panel; and a protruding portion, surrounding and wrapping at least two sides of the at least one printed circuit board, and extending from at least two side surfaces of the mold frame, the at least two side surfaces of the mold frame being connected together.  
         [0021]     The protruding portion preferably extends to connect three sides of the mold frame together.  
         [0022]     An extending height of the protruding portion is preferably equal to or less than a thickness of a side surface of the at least one printed circuit board.  
         [0023]     The at least one printed circuit board preferably corresponds to the protruding portion to be accommodated inside of the protruding portion.  
         [0024]     The portable display device preferably further includes at least one of the first display panel or other display panels being connected to the at least one printed circuit board. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     A more complete appreciation of the present invention and many of the attendant advantages thereof, will be readily apparent as the present invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:  
         [0026]      FIG. 1  is a schematic perspective view of a conventional portable display device.  
         [0027]      FIG. 2  is an exploded perspective view of a portable display device according to an exemplary embodiment of the present invention.  
         [0028]      FIG. 3  is a view of the mold frame of  FIG. 2 .  
         [0029]      FIG. 4  is a rear perspective view of an assembled portable display device of  FIG. 2 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]      FIG. 2  is an exploded perspective view of a portable display device according to an exemplary embodiment of the present invention.  
         [0031]     In  FIG. 2 , a dual display device, such as a cellular phone, includes at least one Liquid Crystal Display. The construction and arrangement of the portable display device is only exemplary and the present invention is not limited thereto.  
         [0032]     Referred to  FIG. 2 , a portable display device  100  includes a first display panel  110 , a back light assembly  170 , a first printed circuit board  180 , a second printed circuit board  185  and second display panel  190 .  
         [0033]     Referring to  FIG. 2 , the first display panel  110  is a liquid crystal display panel; the second display panel  190  is an organic light emitting display panel. The first display panel  110  has broader picture surface to display more information than the second display panel  190 . As an example, the first display panel  110  is used as an internal window of the cellular phone folder and the second display panel  190  is used as an external window of the cellular phone folder.  
         [0034]     In this case, the first display panel  110  displays information of message receipt breakdown and communication information etc., and the second display panel  190  displays relatively information of date and time, etc. The first display panel  110  includes an integrated circuit  112 , first substrate  110   a , second substrate  110   b  and a liquid crystal material which injected in between the first substrate  101   a  and second substrate  110   b.    
         [0035]     The first substrate  110   a  contains multiple Thin Film Transistors (TFTs) positioned in a matrix. The source electrodes of the TFTs are connected to the data lines and the gate electrodes are connected to the scan lines. The drain electrodes of the TFTs are connected to pixel electrodes formed of electro-conductive transparent Indium-Tin Oxide (ITO).  
         [0036]     The TFTs are turned on when the scan signal is provided by the scan lines and provide the pixel electrodes with the data signals. The integrated circuit  112  provides the TFTs with scan signals and data signals at the appropriate time. A protection layer  115  is formed around the integrated circuit  112 . The second substrate  110   b  is located corresponding to the first substrate  10   a . A common electrode formed of ITO is located in front of the second substrate  110   b,    
         [0037]     A predetermined voltage is provided to the common electrode and an electric field corresponding to the voltage is formed in between the pixel electrode and the common electrode.  
         [0038]     According to the electric field, the arrangement angle of the liquid crystal injected in between the first substrate  110   a  and the second substrate  110   b , is changed and due to the changed arrangement angle, it displays the desired images by the changed light transmission.  
         [0039]     The back light assembly  170  contains light emitting diodes  130 , a light emitting diode board  135 , a Light Guide Plate (LGP)  150 , a reflection plate  160 , optical sheets  120 , and a mold frame  140  to contain them therein. The light emitting diodes  130  produce light of a predetermined brightness corresponding to the driving signals from the light emitting diode board  135 . While light emitting diodes  130  are illustrated as a light source, other light sources, such as lamps, can be used.  
         [0040]     Also, the number of light emitting diodes  130  can be varied. The light emitting diode board  135  is connected to the first printed circuit board  180 , and corresponds to the control signals provided by the first printed circuit board  180  The light emitting diode board  135  then provides the light emitting diodes  130  with the driving signals. The LGP  150  provides the first display panel  110  with the light from the light emitting diodes  130 .  
         [0041]     The LGP  150  transmits the light from its side, as a planar light of the first display panel  110  area.  
         [0042]     The reflection plate  160  provides the optical sheets  120  with the light from the LGP  150 .  
         [0043]     The optical sheets  120  provide the first display panel  110  with the light after enhancing uniformity and/or luminance of the light from the LGP  150 .  
         [0044]     The mold frame  140  fixes the light emitting diodes  130 , the LGP  150 , the light emitting diode board  135 , the reflection plate  160 , and the optical sheets  120 . The mold frame  140  contains the protruding portion  140   a  which extends from at least two sides, to the first and the second printed circuit board  180  and  185  to connect each other.  
         [0045]     For instance, the protruding portion  140   a , as illustrated in  FIG. 3 , can be extended to be connected from three sides of the mold frame  140 .  
         [0046]     The protruding portion  140   a  guides an adhesion site to attach the first and the second printed circuit board  180  and  185  to the mold frame  140 .  
         [0047]     Unlike the conventional tip  10   a  of  FIG. 1 , the protruding portion  140   a  extends to be connected to three sides of the mold frame  140 , and is therefore damaged less frequently than the conventional tip  10   a  of  FIG. 1 .  
         [0048]     Also, the protruding portion  140   a , formed on the three sides, is formed to be connected with each other with a           shape, and is formed to wrap three sides of the first and second printed circuit boards  180  and  185  when the first and second printed circuit board  180  and  185  are attached.  
         [0049]     So as not to increase the thickness of the portable display device  100 , the thickness of the protruding portion  140   a  is the same as or less than the thickness of the first and second printed circuit boards  180  and  185  attached thereto, that is, the sum of the side thickness of the first and second printed circuit boards  180  and  185 .  
         [0050]     Since the edge thickness of the mold frame  140  is increased after the protruding portion  140   a  is formed, the stress concentrated on the edge is decreased, and the details thereof are described later. While the protruding portion  140   a  is formed to extend from three sides of the mold frame  140 , it is only for illustration purposes and the present invention is not limited thereto.  
         [0051]     For example, the protruding portion  140   a  may be extended to connect four side surfaces of the mold frame  140  with each other. In this case, a groove, opening, etc., can be formed where the cellular phone connector  187  is located.  
         [0052]     Also, the thickness of the mold frame  140  is the same or less than the sum of the side thickness of the first and second printed circuit boards  180  and  185 . However, it can be formed so as not to exceed the total side thickness of the first and second printed circuit boards  180  and  185  and the second display panel  190 .  
         [0053]     The second printed circuit board  185  receives the driving signals from the driving circuit (not shown) of the cellular phone.  
         [0054]     To do this, the second printed circuit board  185  contains the cellular phone connector  187 . The cellular phone connector  187  is combined with another connector attached to the driving circuit in the cellular phone and receives the driving signals from the driving circuit in the cellular phone.  
         [0055]     The second printed circuit board  185  receiving driving signals produces variable control signals corresponding to the driving signals provided thereto. The first printed circuit board  180  is connected to the second printed circuit board  185  through a first pad  189  formed on the second printed circuit board  185 . The first printed circuit board  180  is connected to the integrated circuit  112  of the first display panel  110  and the light emitting diode board  135  by a flexible printed circuit board (not shown).  
         [0056]     The first printed circuit board  180  connected to the integrated circuit  112  and the light emitting diode board  135  drives the integrated circuit  112  and the light emitting diode board  135  corresponding to the control signals supplied from the second printed circuit board  180 .  
         [0057]     The edges of the first and second printed circuit boards  180  and  185  are molded to correspond to the protruding portion  140   a  of the mold frame  140 .  
         [0058]     The second display panel  190  is formed with an organic light emitting display panel. The second display panel  190  is connected to a flexible printed circuit board  192 , and the flexible printed circuit board  192  is connected to the second printed circuit board  185  through a second pad  197 . The flexible printed circuit board  192  contains an integrated circuit  195 , and the integrated circuit  195  drives the second display panel  190  corresponding to the control signals supplied by the second printed circuit board  185 , and the second display panel  190  then displays an image.  
         [0059]     The second display panel  190  can be formed as a Liquid Crystal Display panel. In this case, multiple optical sheets may be formed in between the light guide plate  150  and the second display panel  190  and there may be an opening corresponding to the second display panel  190  within the first and second printed circuit boards  180  and  185 .  
         [0060]     Also, while not illustrated in  FIG. 2 , the portable display device  100  may contain a chassis installed in the upper and lower portions of the mold frame  140 .  
         [0061]      FIG. 4  is a rear perspective view of an assembled portable display device of the  FIG. 2 .  
         [0062]     Referring to  FIG. 4 , the second printed circuit board  185  which wrapped the side surface by the extended protruding portion  140   a  with a           shape on three side surfaces of the mold frame  140 , is attached to the mold frame  140  by double-sided adhesive tape, etc., while, the side surface thickness of the protruding portion  140   a  is no more than the sum of thickness of first and second printed circuit boards  180  and  185  and second display panel  190 .  
         [0063]     Thus, the protruding portion  140   a  is formed with surrounding wrapped three side surfaces of the second printed circuit board  185 , the thickness of the mold frame  140  which formed the protruding portion  140   a  is increased as much as the thickness p of the protruding portion  140   a . That is, the side surface thickness d′ of the mold frame  140  which formed protruding portion  140   a , is the sum of the side surface thickness d of the mold frame  140  and the thickness p of the protruding portion  140   a.    
         [0064]     The side surface of mold frame  140  corresponding to the side surface of second printed circuit board  185  which formed the connector  187  of cellular phone, is not formed with the protruding portion  140   a , and thus, is easier to align.  
         [0065]     Generally, the stress applied from the external portion, is concentrated on the side surface edge portion, and while, the durability of the mold frame  140  is improved by increasing of the side thickness thereof. The stress, which added to the mold frame  140 , is decreased, against the same external power according to increasing of the thickness of mold frame  140 , and thus, the displacement is decreased also and therefore, the durability of the mold frame  140  is improved.  
         [0066]     Therefore, the durability of the portable display device  100  is improved.  
         [0067]     Also, the first and second printed circuit boards  180  and  185  are molded to be attachable on the inside of the protruding portion  140   a , the side surface thickness of the protruding portion  140   a  is no more than the sum of thickness of the first and second printed circuit boards  180  and  185  and second display panel  190 , and thus, the whole thickness d′ of portable display  100  is not increased, even if increasing of the side thickness of the mold frame  140 .  
         [0068]     As described above, according to the exemplary embodiment of the present invention, even if the whole thickness of the portable display device  100  is maintained same, the durability of the portable display device is improved by the change of the figure of the mold frame  140  and first and second printed circuit boards  180  and  185  which are mounted on the mold frame  140 .  
         [0069]     Thus, in the portable display device according to the present invention, the durability of the portable display device is improved through the change of the figure of printed circuit board which is mounted in alignment with wrapping the side surfaces by the protruding portion on the inside and the protruding portion which is formed on the mold frame.  
         [0070]     Although an exemplary embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as defined by the accompanying claims.