Abstract:
An apparatus for disassembling a display screen device. The apparatus comprises: 1) a container configured to receive liquid nitrogen into a liquid nitrogen chamber within the container, wherein at least one portion of the container has at least one vent hole that enables cold nitrogen gas to escape from the container; and 2) a cover configured to be brought into contact with the container to thereby form a nitrogen gas chamber that receives the nitrogen gas escaping from the container. The display screen device is disposed within the nitrogen gas chamber. The nitrogen gas freezes exposed surfaces of the display screen device. An adhesive layer disposed in a cooling area of the display screen device proximate an exposed surface loses it adhesiveness as the cooling area becomes colder. The apparatus further comprises an insulation pad disposed within the nitrogen gas chamber and configured to be brought into contact with a protected surface of the display screen device. The insulation pad creates a cooling protect area within the display screen device proximate the protected surface.

Description:
TECHNICAL FIELD 
       [0001]    The present application relates generally to an apparatus and method for disassembling a curved or bendable display screen during repair of the display screen. 
       BACKGROUND 
       [0002]    The high cost of many smartphones makes it economically viable to repair a damaged smartphone rather than replace it. While a consumer might well throw away an inexpensive cellphone if the screen cracked after being dropped, the consumer will instead repair an expensive smartphone. As a result, there is a substantial market for replacing cracked screens and other parts of smartphones. 
         [0003]    One common method of separating the parts of a smartphone uses liquid nitrogen (N 2 ) that is poured on the screen of the smartphone. The top glass layer of a smart phone is typically adhered to the layers of the touch screen below it by means of a layer of optical clear adhesive. After a few seconds of the liquid nitrogen resting on the surface of the glass, the optical clear adhesive freezes and loses its adhesive properties. A simple tap on the glass is then sufficient to separate the glass layer from the touch screen components. 
         [0004]    Recently, however, curved screens and bendable screens have entered the smartphone marketplace. The surface glass of these devices is not flat and the components and materials for the display assembly are significantly different than those in flat screen displays. Also, removing these screens is further complicated because the liquid nitrogen will simply run off the curved surface of the glass. Therefore, there is a need for improved techniques for repairing the curved and/or flexible screens of a smartphone. There is a further need for a device that will optimize the environment and conditions in using liquid nitrogen that will prevent defects when the temperature is very low and the surface screen is being separated. 
       SUMMARY 
       [0005]    To address the above-discussed deficiencies of the prior art and to develop technologies that are compatible to the new display changes, it is a primary object to provide an apparatus for disassembling a display screen device including curved and bendable touch display screen device. The apparatus comprises: 1) a container configured to receive liquid nitrogen into a liquid nitrogen chamber within the container, wherein at least one portion of the container has at least one vent hole that enables cold nitrogen gas to escape from the container; and 2) a cover configured to be brought into contact with the container to thereby form a nitrogen gas chamber that receives the nitrogen gas escaping from the container. The display screen device is disposed within the nitrogen gas chamber. 
         [0006]    According to one embodiment, the nitrogen gas freezes exposed surfaces of the display screen device. 
         [0007]    According to another embodiment, an adhesive layer disposed in a cooling area of the display screen device proximate an exposed surface loses it adhesiveness as the cooling area becomes colder. 
         [0008]    According to still another embodiment, the apparatus further comprises an insulation pad disposed within the nitrogen gas chamber and configured to be brought into contact with a protected surface of the display screen device. 
         [0009]    According to yet another embodiment, the insulation pad creates a cooling protect area within the display screen device proximate the protected surface. 
         [0010]    According to a further embodiment, an adhesive layer disposed in the cooling protect area of the display screen device retains its adhesiveness as other portions of the display screen device become colder. 
         [0011]    It is another object to provide a method of disassembling a display screen device. The method comprises: 1) using nitrogen gas to partially freeze a first part of the display screen device; 2) waiting until an adhesive layer in the first part of the display screen device cools sufficiently to lose its adhesiveness; and 3) separating the first part of the display screen device from the remainder of the display screen device. 
         [0012]    In one embodiment, using nitrogen gas comprises: i) evaporating liquid nitrogen to form the nitrogen gas; and ii) exposing the first part of the display screen device to the nitrogen gas. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
           [0014]      FIG. 1  ( FIG. 1 ) illustrates a conventional touch screen device according to an embodiment of the disclosure. 
           [0015]      FIG. 2  ( FIG. 2 ) is a flow diagram illustrating a process for separating parts of a touch screen device according to an embodiment of the disclosure. 
           [0016]      FIG. 3  ( FIG. 3 ) illustrates an apparatus for separating the rear case part of a touch screen device according to an embodiment of the disclosure. 
           [0017]      FIG. 4  ( FIG. 4 ) is a detailed view of a portion of the apparatus in  FIG. 3  according to an embodiment of the disclosure. 
           [0018]      FIG. 5  ( FIG. 5 ) illustrates an apparatus for separating the cover glass part of a touch screen device according to another embodiment of the disclosure. 
           [0019]      FIGS. 6A  ( FIG. 6A ) and  FIG. 6B  ( FIG. 6B ) illustrate a detailed view of a portion of an apparatus similar to the apparatus in  FIG. 3  according to an alternate embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIGS. 1 through 6 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus for repairing display screens. 
         [0021]    The present disclosure describes a technique that uses very cold nitrogen (N 2 ) gas in place of liquid nitrogen to freeze and separate the components of any electronic device that uses adhesives to attach component layers. Such electronic devices may include a smartphone, including a touch screen of a smartphone device. 
         [0022]      FIG. 1  illustrates conventional touch screen device  100  according to an embodiment of the disclosure. Device  100  comprises curve touch screen part  110  and rear case part  120 . Curved touch screen part  110  comprises cover glass part  130  and touch screen panel part  140 . Rear case part  120  comprises adhesive layer  121  and rear cover case  122 . Cover glass part  130  comprises tempered cover glass  131  and optical clear adhesive layer  132 . Touch screen panel part  140  comprises indium tin oxide (ITO) film  141 , adhesive layer  142 , polarizer film layer  143 , adhesive layer  144 , and flexible display  145 . 
         [0023]    Optical clear adhesive layer  132  is a clear adhesive that attaches tempered cover glass  131  to ITO film layer  141 . At normal environmental temperatures, the adhesive properties of optical clear adhesive layer  132  are strong. However, at very low temperatures, the adhesiveness of optical clear adhesive layer  132  greatly diminishes and a slight tap can separate tempered cover glass  131  from ITO film layer  141 . Similarly, adhesive layer  121  attaches rear cover case  122  to the back surface of flexible display  145 . At very low temperatures, the adhesiveness of adhesive layer  121  greatly diminishes and a slight tap can separate rear cover case  122  from flexible display  145 . 
         [0024]      FIG. 2  depicts flow diagram  200 , which illustrates a process for separating parts of touch screen device  100  according to an embodiment of the disclosure. A partial cooling chamber as disclosed in  FIGS. 3-5  may be used to perform the process in  FIG. 2 . Initially, rear cover case  122  is removed using a partial cooling chamber that partially freezes part of device  100  (e.g., the outer surface of rear cover case  122 ) (step  210 ). Next, using the partial cooling chamber, cover glass part  130  is removed by partially freezing part of device  100  (e.g., outer surface of tempered cover glass  131  (step  220 ). At this point, both cover glass part  130  and rear case part  120  have been removed from touch screen panel part  140 . Next, the separated components may be washed in a solvent to remove unwanted residue from the steps above (step  260 ). In an advantageous embodiment, the solvent used may be ISOPAR G fluid, which is available from ExxonMobil Chemical Company. ISOPAR G fluid comprises C9-11 isoalkanes (70%) and C10-13 isoalkanes (30%). 
         [0025]    Next, device  100  may be reassembled using new replacement parts. A new layer of optical clear adhesive layer  132  is deposited on tempered cover glass  131  to form new cover glass part  130  (step  240 ). Using a vacuum laminator, new/repaired cover glass part  130  is attached to touch screen panel part  140  (step  250 ). Next, new adhesive layer  121  is added to rear cover case  122  to form new/repaired rear case part  120  (step  260 ). Thereafter, curved touch screen panel  110  and new rear case part  120  are assembled to form a repaired touch screen device  100  (step  270 ). 
         [0026]      FIG. 3  illustrates a cross-sectional view of apparatus  300  for separating parts of touch screen device  100  according to an embodiment of the disclosure. Apparatus  300  comprises cover  310 , bottom wall  321 , sidewalls  322   a  and  322   b,  top wall  323 , and heating elements  340  and  345 . Bottom wall  321 , sidewalls  322   a  and  322   b,  and top wall  323  define liquid nitrogen chamber  320 . Liquid nitrogen is introduced into chamber  320  by hose  325 . The liquid nitrogen evaporates into nitrogen gas as heating elements  340  and  345  warm the ambient air outside of chamber  320 . The frigid nitrogen gas escapes from chamber  320  through vent holes  324  in top wall  323 . 
         [0027]    Touch screen device  100  is positioned above top wall  323  and underneath cover  310 . When cover  310  is lowered by means of drive rod  350  and spring  355  (or other mechanical means), cover  310  forms a seal with the periphery of top wall  323  and creates nitrogen gas chamber  330  between cover  310  and top wall  323 . The cold nitrogen gas escaping through vent holes  324  then fills nitrogen gas chamber  330  and freezes the exposed surfaces of touch screen device  100 . When cover  310  is lowered, cover  310  also presses insulation pad  305  into contact with the upper surface of touch screen device  100 , thereby protecting the region of touch screen device beneath insulation pad  305  from being frozen by the nitrogen gas. 
         [0028]      FIG. 4  is a detailed view of a portion of the apparatus in  FIG. 3  according to an embodiment of the disclosure. Insulation pad  305  is pressed into contact with the upper surface of touch screen device  100 . As nitrogen gas cools the exterior of device  100 , insulation pad  305  creates cooling protect area  410  that remains warmer than the rest of the body of device  100  (i.e., cooling area  420 . Thus, any adhesive layer that is in cooling protect area  410  will remain relatively warm and retain its adhesive properties, while any adhesive layer that is in cooling area  420  will loses its adhesiveness. 
         [0029]    In an exemplary embodiment, cooling protect area  410  may be cooled to between 0° C. and −30° C. and cooling area  420  may be cooled to between −40° C. and −80° C. Due to its thinness, tempered cover glass  131  may be cooled for between 7 seconds and 35 seconds. Rear case part  120  may be cooled for between 35 seconds and 70 seconds. For a small apparatus  300  or  500  that is sufficient in size to hold a smartphone, approximately 200-400 milliliters of liquid nitrogen may be used. 
         [0030]      FIG. 5  illustrates a cross-sectional view of apparatus  500  for separating parts of touch screen device  100  according to another embodiment of the disclosure. Apparatus  500  comprises cover  510 , bottom walls  521   a  and  521   b,  sidewalls  522   a,    522   b,    522   c,  and  522   d,  and heating element  510 . Bottom walls  521   a  and  521   b,  and sidewalls  522   a - 522   d,  and cover  510  define liquid nitrogen chamber  530 . Liquid nitrogen is introduced into chamber  530  by hoses  525   a  and  525   b.  The liquid nitrogen evaporates into nitrogen gas as heating element  510  and other heating elements (not shown) warm the ambient air outside of chamber  530 . The frigid nitrogen gas escapes from chamber  530  through vent holes  524  in cover  510 . The hoses  525   a  and  525   b  are shown passing through the sidewalls  5222   a  and  522   d.  In an alternate embodiment, one or both of hoses  525   a  and  525   d  may pass through cover  510 . 
         [0031]    Touch screen device  100  is positioned below cover  510  and above the surface (not shown) on which apparatus  500  rests. When cover  510  is lowered by mechanical means (not shown), cover  510  forms a seal with the top edges of sidewalls  522   a - 522   d  and creates liquid nitrogen gas chamber  530 . Lowering cover  510  also creates nitrogen gas chamber  520  between cover  510  and the surface on which apparatus  500  rests. The cold nitrogen gas escaping through vent holes  524  then fills nitrogen gas chamber  530  and freezes the exposed surfaces of touch screen device  100 . Touch screen device  100  rests on insulation pad  505 , thereby protecting the region of touch screen device above insulation pad  505  from being frozen by the nitrogen gas. This protected region is similar to cooling protect area  410  in  FIG. 4 . 
         [0032]    Advantageously, either one of apparatus  300  and apparatus  500  may be used to perform the repair process in  FIG. 2 . In either case, nitrogen gas surrounds and freezes the exposed surfaces of touch screen device  100  to thereby create a cooling area  420  within the body of device  100 . An adhesive layer within the cooling area  420  will lose its adhesive properties, so that components that are attached to each other by such a frozen adhesive layer are easily separated by tapping. In contrast, an adhesive layer within cooling protect area  410  retains its adhesiveness, so that components that are attached by such an adhesive layer will not separate by tapping. 
         [0033]    Liquid nitrogen is usually at a temperature of around −195° Celsius and as it becomes gaseous nitrogen in the gas chamber, the temperature of the nitrogen slowly increases. A good temperature to separate the screen is approximately around −147° Celsius. Because the temperature of the nitrogen increases, it is important to create a short pathway to change from liquid state to gaseous state so that the chamber may maintain approximately −147° Celsius to separate the screen. Using gaseous nitrogen uses a smaller amount of nitrogen comparing to directly applying liquid nitrogen to a display screen device. In addition, by using a gas chamber, the gaseous nitrogen may be more evenly distributed than by directly applying liquid nitrogen. 
         [0034]      FIGS. 6A and 6B  illustrates a detailed view of a portion of apparatus  600 , which is similar to apparatus  300  in  FIG. 3  according to an alternate embodiment of the disclosure. Those skilled in the art will understand in another alternate embodiment, apparatus  600  may be implement as a modification to apparatus  500  in  FIG. 5 . For simplification, many of the components in  FIG. 3  have been omitted in  FIG. 6  as they are not necessary to explain the operation of apparatus  600 . 
         [0035]    As in the previous embodiments, apparatus  600  comprises top wall  623 , which includes a plurality of vent holes  624 . Top wall  623  further includes protrusion  650  on the surface of top wall  623  that faces touch screen device  100 . Protusion  650  may be a simple bump or ridge on top wall  623 . In  FIG. 6A and 6B , it should be understood that device  100  and protusion  650  are not intended to be shown to scale. In  FIGS. 6A and 6B , cover  610  may represent both a cover and an insulation pad as in the previous embodiments in  FIGS. 3 and 5 . 
         [0036]    In  FIG. 6A , cover  610  has not yet been pressed downward (as indicated by arrows) on device  100 . Device  100  includes a bendable screen that is substantially flat prior to cover  610  being pressed downward. In  FIG. 6B , however, cover  610  has been pressed down onto device  100 , thereby pressing device  100  onto protusion  650 . The effect is to bend the screen of device  100  as shown in  FIG. 6B  (bending not to scale). This bending by protustion  650  causes the touch screen panel part  140  to more easily separate from the other parts of device  100 . 
         [0037]    Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.