Abstract:
The present invention relates to an integrated device ( 10 ) comprising at least one active organic element ( 14, 24, 26 ), a substrate supporting the at least one active organic element, a prefabricated thin battery ( 20 ) coupled to the at least one active organic element, and an encapsulation for sealing the integrated device, wherein one of the substrate and the encapsulation is formed by the prefabricated thin battery. This structure allows for a thin integrated device. The present invention also relates to a method for the manufacturing of such an integrated device.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to an integrated device comprising at least one active organic element and a thin battery coupled to the at least one active organic element. The present invention also relates to a method for the manufacturing of such an integrated device. 
       BACKGROUND OF THE INVENTION 
       [0002]    An example of a device comprising an active organic element and a battery is disclosed in the document WO03019658. More precisely, the device in WO03019658 comprises, from bottom to top, a substrate (such as glass or a flexible film), an energy carrier (battery or photovoltaic cell), a semitransparent insulation layer serving as a substrate for an organic light emitting diode (OLED), and finally an encapsulation or seal, which is comprised of glass. Upon operation, the energy carrier supplies a voltage that causes the OLED to emit light. 
         [0003]    In one particular embodiment, the energy carrier and the OLED are produced on opposite sides of the semitransparent insulation layer, and the bottom substrate instead acts as a seal for the energy carrier. Thus, the OLED and the energy carrier are sealed separately. The sealing is necessary for avoiding influx of water and oxygen that otherwise would deteriorate the device performance. 
         [0004]    However, the structure disclosed in WO03019658 yields a relatively thick and expensive package since the energy carrier and the OLED are encapsulated and sealed separately. To this end, for many applications, small thickness and low cost are important factors. Also, the energy carrier is fabricated with a thin film technology, which results in high cost. 
       SUMMARY OF THE INVENTION 
       [0005]    It is an object of the present invention to overcome this problem, and to provide an improved, integrated device with reduced thickness. 
         [0006]    This and other objects that will be evident from the following description are achieved by means of an integrated device, and a method for the manufacturing of such an integrated device, according to the appended claims. 
         [0007]    According to an aspect of the invention, there is provided an integrated device comprising at least one active organic element, a substrate supporting the at least one active organic element, a prefabricated thin battery coupled to the at least one active organic element, and an encapsulation for sealing the integrated device, wherein one of the substrate and the encapsulation is formed by the prefabricated thin battery. 
         [0008]    Thus, the prefabricated battery gets the function also to act as top encapsulation of the device or act as a supporting and/or protective substrate of the device. This yields a thinner and more robust device compared to prior art structures since a separate encapsulation/substrate can be omitted. Due to the battery, the device may operate autonomously. 
         [0009]    Preferably, the battery covers the complete active organic element area, so that it will not be exposed to water and/or air. 
         [0010]    In one embodiment, the substrate is a transparent substrate, the at least one active organic element is processed on the transparent substrate, and the prefabricated thin battery is arranged on top of the at least one active organic element. Thus, here the prefabricated battery acts as the encapsulation of the integrated device. Further, the transparent substrate can be made of a flexible material, allowing the complete device to be flexible. 
         [0011]    In another embodiment, the prefabricated thin battery is attached to the at least one active organic element, and an encapsulating coating is provided on the other side of the at least one active organic element compared to the battery. Thus, here the prefabricated battery acts as the substrate of the integrated device. 
         [0012]    In one embodiment, the at least one active organic element is an OLED, and the battery is adapted to power the OLED. The OLED may for example be a display or a light source. 
         [0013]    In another embodiment, the at least one active organic element is an organic sensor, and the battery is adapted to power the organic sensor. The sensor may for example be a photo-sensor, an organic switch, a rectifying diode, etc. 
         [0014]    In another embodiment, the at least one active organic element is an organic photovoltaic cell, and the photovoltaic cell is adapted to charge the battery. In another embodiment, the at least one active organic element comprises an OLED and an organic photovoltaic cell arranged adjacent to each other, the organic photovoltaic cell is adapted to charge the battery, and the battery is adapted to power the OLED. The adjacent OLED and organic photovoltaic cell can advantageously be processed on the same substrate at the same time, which is very cost efficient. 
         [0015]    In one embodiment, the device further comprises a second OLED provided on the other side of the thin battery compared to the at least one active organic element. Such a device may provide for a double-sided display (in case the first organic element also is an OLED), or a two color lamp, for example. 
         [0016]    In one embodiment, a fixing agent is applied around the at least one active organic element and between the at least one active organic element and the prefabricated thin battery, which fixing agent comprises a getter material. The getter material is a water absorbing material, such as calcium oxide. Thus, the fixing agent serves to join the at least one active organic element and the prefabricated thin battery, as well as to protect the at least one active organic element from moisture from the sides of the device. 
         [0017]    According to another aspect of the invention, there is provided a method for the manufacturing of an integrated device, comprising providing a transparent substrate, processing at least one active organic element on the transparent substrate, and arranging a prefabricated thin battery on top of the at least one active organic element for sealing the integrated device. Thus, here the prefabricated battery acts as the encapsulation of the integrated device. 
         [0018]    In one embodiment, the method further comprises providing an encapsulating coating on the transparent substrate on the side of the substrate where the at least one active organic element is to be processed, and removing the transparent substrate after the at least one active organic element has been processed. Thus, here the prefabricated battery acts as the substrate of the integrated device. Preferably, the transparent substrate is removed after the prefabricated battery has been arranged on top of the at least one active organic element. The prefabricated thin battery may be arranged on top of the at least one active organic element by means of lamination, for example. 
         [0019]    In one embodiment, the method further comprises filling the battery with electrolyte after the battery is laminated on top of the at least one active organic element. Before the battery is filled with the electrolyte, it is much flatter and will therefore laminate better, which in turn improves the sealing property of the battery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing currently preferred embodiments of the invention. 
           [0021]      FIG. 1  is a schematic cross-sectional side view of an integrated device comprising a single active organic element according to an embodiment of the invention, 
           [0022]      FIG. 2  is a schematic cross-sectional side view of an integrated device comprising an OLED and a photovoltaic cell according to another embodiment of the invention, and 
           [0023]      FIGS. 3   a - 3   b  are schematic cross-sectional side views illustrating steps of manufacturing of an integrated device according to another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0024]      FIG. 1  is a cross-sectional side view of an integrated device  10  according to an embodiment of the invention. From bottom to top in  FIG. 1 , the integrated device  10  comprises a transparent substrate  12  onto which an organic light emitting diode (OLED)  14  is processed. The OLED  14  may be processed by means of printing or deposition or evaporation through a shadow mask, for example. The transparent substrate  12  may be made glass or plastics, for example. Also, it can be made of a flexible material, allowing the complete device  10  to be flexible, and the OLED  14  may function as a display or as a light source. 
         [0025]    The substrate  12  and the OLED  14  are coated with a thin-film packaging layer  16 , for example a NONON-stack (silicon nitride-silicon oxide-silicon nitride-silicon oxide-silicon nitride). On the layer  16 , a topcoat  18  is applied, and on top of the topcoat  18 , a prefabricated thin battery  20  is attached. The prefabricated thin battery  20  covers the complete OLED area. The topcoat  18  may function as a glue, and the prefabricated thin battery  20  is preferably laminated onto the topcoat  18 . Also, a water absorbing getter material such as calcium oxide, CaO, may be incorporated in the glue  18 , to protect the OLED  14  (or any other active organic element(s)) from moisture from the sides of the device. Also, a rim of standard glue (not shown) could be applied around the device except for the battery, to reduce water penetration and thereby further protect the device. The battery  20  is adapted to power the OLED  14  causing the OLED  14  to emit light (illustrated by arrows  22 ) during operation of the device  10 . The battery  20  is prefabricated in a sense that incorporating the battery in the device mainly includes assembling the battery with the rest of the device. 
         [0026]    No other coating or sealing has to be provided on top of the prefabricated battery  20 . Thus, here the prefabricated thin battery  20  acts as a top side encapsulation of the device  10 , avoiding the use of any dedicated top encapsulation or sealing. To this end, the prefabricated thin battery  20  should be flat and impermeable with respect to water (water tight) and/or air. An exemplary prefabricated battery having such properties is the Lithylene batteries by Philips. Also, in case the substrate  12  is flexible or omitted, the prefabricated battery should be flexible to realize a complete flexible device. Also, during manufacturing of the integrated device, for some batteries (such as the Lithylene battery, and NiCd— and NiMh batteries) it may be beneficial to fill the battery with electrolyte after mounting of the battery to the device, since the battery is much flatter without the electrolyte. It will then better laminate and therefore seal better. 
         [0027]    In the integrated device  10  illustrated in  FIG. 1 , the thickness of the prefabricated battery  20  may be in the order of 500 μm, the thickness of the topcoat  18  in the order of 10 μm, the thickness of the layer  16  in the order of 1 μm, and the thickness of the substrate  12  in the order of 700 μm, rendering a total device thickness of about 1200 μm. 
         [0028]    The above mentioned OLED  14  may in alternative embodiments be replaced by an organic sensor  24 , such as a photo-sensor, or an organic photovoltaic cell (e.g. solar cell)  26 . In the former case, the battery  20  powers the organic sensor  24 , whereas in the latter case, the organic photovoltaic cell  26  charges the battery  20 . Also, an additional OLED  30  may optionally be provided on the other side of the prefabricated battery  20  compared to the OLED  14 /organic sensor  24 /organic photovoltaic cell  26 . Such a device may provide for a double-sided display (in case the first organic element also is an OLED), or a self powered lamp (in case the first organic element is a photovoltaic cell), for example. 
         [0029]      FIG. 2  is a cross-sectional side view of an integrated device  10  according to another embodiment of the invention. The device of  FIG. 2  is similar to that of  FIG. 1 , except in that an organic photovoltaic cell  26  is provided on the substrate  12  adjacent to the OLED  14 . The prefabricated battery  20  still functions as top encapsulation of the device  10 . The organic photovoltaic cell  26  is adapted to charge the battery  20 , and the battery  20  is adapted to power the OLED  14 . Thus, an autonomous device is realized. The anode and cathode (not shown) of the device  10  are preferably structured so as to allow separate coupling of the OLED  14  and the photovoltaic cell  26 . 
         [0030]    An OLED and an organic photovoltaic cell are structurally very similar. They both comprises a buffer layer and an organic active layer sandwiched between an anode and a cathode. The only difference is the type of organic active layer material. In an OLED, the organic active layer material is adapted to emit light (examples of such a material comprise derivatives of PPV and poly(fluorene)), whereas in an organic photovoltaic cell, the organic active layer material is adapted to convert light into electrical energy (an example of such a material comprises a conjugated polymer/fullerene blend). Therefore, the OLED  14  and organic photovoltaic cell  26  can advantageously be processed on the substrate  12  at the same time using the same processing steps, only using different organic active layer materials. The OLED  14  and organic photovoltaic cell  26  may for example be printed or evaporated through a shadow mask onto the substrate  12 . 
         [0031]      FIGS. 3   a - 3   b  are cross-sectional side views illustrating steps of manufacturing of an integrated device  10  according to another embodiment of the invention. The device  10  illustrated in  FIG. 3   a  is similar to that of  FIG. 1 , except in that an encapsulating coating  32  and a polymer coating  28  are applied between the glass substrate  12  and the OLED  14 /organic sensor  24 /organic photovoltaic cell  26 . The encapsulating coating  32  may be of the same material as the layer  16 , and the polymer coating  28  may be made of polyimide. Conveniently, in manufacturing, the coatings are applied to the substrate  12  before the OLED  14 /organic sensor  24 /organic photovoltaic cell  26  is processed thereon. The substrate  12  may then be released from the polymer coating  28  by means of laser according to the EPLAR process (Electronics on Plastic by Laser Release) as illustrated in  FIG. 3   b , leaving a final device  10  without the substrate  12 , where instead the prefabricated thin battery  20  acts as the device substrate. Without the glass substrate  12 , a complete flexible integrated device  10  can be realized using a flexible battery. However, a rigid device without the substrate  12  is also contemplated. 
         [0032]    There are many possible applications for the present invention. The small size of the integrated device makes it particularly useful for use in handheld apparatuses. For example, the integrated device with an OLED display may be incorporated in handheld electronic apparatus such as a mobile phone, a PDA, or a digital media player. The integrate device with one OLED display one each side of the battery (i.e. a double sided display) may be incorporated in a flip-phone. The integrated device with an OLED light source can be used as a standalone emergency light, reading light, underwater light, etc. The integrated device with an OLED and an organic photovoltaic cell can be used as a standalone lamp or display independent of an external power supply. The integrated device with an organic photovoltaic cell can for example be used as a renewable power source in various apparatuses, especially where small size is an issue, such as in an electronic credit card. The integrated device with an organic sensor may be used in combination with an OLED for switching or control purposes. 
         [0033]    The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the prefabricated battery may act as a substrate and the glass substrate may be released (as explained in relation to  FIGS. 3   a - 3   b ) also in the embodiment with both an OLED and an organic photovoltaic cell illustrated in  FIG. 2 . Also, several organic active elements, for example two or more OLEDs, may be provided on the substrate.