Abstract:
An electronic assembly and method for making the same includes a flexible substrate and a protective layer arranged adjacent to one side of the substrate. The protective layer has a first thickness and defines at least one hole. A first electrical component has a second thickness that is less than or equal to the first thickness. The first electrical component is received in the hole in the protective layer.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to printing and/or assembly of electronic components on a printing web.  
       BACKGROUND OF THE INVENTION  
       [0002]     Integrated circuits (ICs) are the basic building blocks that are used to create electronic devices. Continuous improvements in IC process and design technologies have led to smaller, more complex, and more reliable electronic devices at a lower cost per function. As performance has increased and size and cost have decreased, the use of ICs has expanded significantly.  
         [0003]     For example, radio frequency identification (RFID) technology incorporates the use of electromagnetic or electrostatic radio frequency (RF) coupling to an IC. Traditional forms of identification such as barcodes, cards, badges, tags, and labels have been widely used to identify items such as access passes, parcels, luggage, tickets, and currencies. However, these forms of identification may not protect items from theft, misplacement, or counterfeit, nor do they allow “touch-free” tracking.  
         [0004]     More secure identification forms such as RFID technology are an attractive alternative to traditional identification and tracking. RFID does not require physical contact and is not dependent on line-of-sight for identification. RFID technology is widely used today at lower frequencies, such as 13.56 MHz, in security access and animal identification applications. Higher-frequency RFID systems ranging between 850 MHz and 2.5 GHz have recently gained acceptance and are being used in vehicular tracking and toll collecting applications and in manufacturing and distribution applications.  
         [0005]     An RFID system includes at least three major components. A transponder component, which usually includes an IC that is embedded within a tag or the like, is electronically programmed with unique identification and/or other information about the item. The smaller the transponder component, the easier it is to attach to a host such as a product, a label, or other objects. A transceiver component contains a decoder and communicates with transponders that are within range. Multiple transceivers can be used to extend the range capabilities of RFID. An antenna component is connected to the transponder.  
         [0006]     In business establishments that use RFID technology to monitor for shoplifting, transceivers are commonly placed near store exits. Each product contains a transponder that is placed within the packaging. Unless the transponder that is associated with a product is deactivated, the transponder will emit a RF signal. The transceiver receives the RF signal and triggers an alarm. A growing number of industries are using or have plans to use RFID technology in the near future. However, current manufacturing processes limit the speed of manufacture and the cost reduction of mass-producing RFID transponders.  
         [0007]     With reference to  FIGS. 1 and 2 , exemplary RFID tags  10  and  12  according to the prior art are shown. In general, RFID tags  10 A and  10 B (collectively 10) each include an IC or other rigid electrical component  20 , an antenna  22 , a substrate  24 , pressure sensitive adhesive  26  and a release liner  28 . A conductive adhesive  29  is used to attach the IC  20  to the antenna  22  and provides an electrical connection therebetween. The RFID tag  10  may include a potting compound  30  or other material arranged over the IC  20  for protection as shown in  FIG. 1 . Alternatively the RFID tag  12  may incorporate a laminate layer  32  that is attached over the antenna  22  and IC  20  as shown in  FIG. 2 . When printing RFID tags  10  in large quantities, it is typical to roll a group of RFID tags  10  into a roll  34  shown in  FIG. 3A . A radial cross section of the roll  34  is shown in  FIG. 3B . As can be appreciated, the difference in rigidity between integrated circuit  20  and the ductile properties of the conductive adhesive  29 , antenna  22  and substrate  24  can lead to mechanical fatigue and/or failure of the RFID tags  10 ,  12 . Similar failures may occur when the RFID tags are singulated and stacked.  
       SUMMARY OF THE INVENTION  
       [0008]     An electronic assembly and method for making the same includes a flexible substrate and a protective layer arranged adjacent to one side of the substrate. The protective layer has a first thickness and defines at least one hole. A first electrical component has a second thickness that is less than or equal to the first thickness. The first electrical component is received in the hole in the protective layer.  
         [0009]     According to other features, the electronic structure further includes a second electrical component that is attached and/or printed on the substrate. The first electrical component is attached to the second electrical component. A conductive adhesive attaches the first electrical component to the second electrical component. In one form, the protective layer includes double-sided tape. In another form, the protective layer includes pressure sensitive adhesive and a release liner.  
         [0010]     In some embodiments, the first electrical component includes an RFID integrated circuit and the second electrical component includes an antenna. The flexible substrate may include a printing web.  
         [0011]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0013]      FIG. 1  illustrates a first exemplary integrated electronic assembly according to prior art;  
         [0014]      FIG. 2  illustrates a second exemplary integrated electronic assembly according to prior art;  
         [0015]      FIG. 3A  illustrates a roll of integrated electronic assemblies according to prior art;  
         [0016]      FIG. 3B  is a cross section of the integrated electronic assemblies of  FIG. 3A  according to prior art;  
         [0017]      FIG. 4  illustrates an exemplary integrated electronic assembly shown in a pre-installed position according to the present teachings;  
         [0018]      FIG. 5  illustrates the integrated electronic assembly of  FIG. 4  shown in an installation position;  
         [0019]      FIG. 6  illustrates the integrated electronic assembly of  FIG. 5  shown in an installed position;  
         [0020]      FIG. 7  illustrates assembly steps for making the integrated electronic assembly of  FIG. 4 ;  
         [0021]      FIG. 8A  illustrates a roll of integrated electronic assemblies according to the present teachings; and  
         [0022]      FIG. 8B  is a cross sectional view of integrated electronic assemblies of  FIG. 8A  according to the present teachings. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. While present invention is being described in conjunction with RFID technology, it can also be applied to other rigid electronic devices that are attached to printing webs.  
         [0024]     Referring now to  FIG. 4 , a sectional view of an electronic assembly  40  is shown to generally include a substrate  42 , an electronic structure  44 , a graphics layer  46  and a protective layer  48 . The substrate  42  can be any packaging material, such as plastic, Mylar, cardboard, paper, or another suitable material known to those skilled in the art, that is conducive to the brand manufacturer&#39;s specifications and the printing and/or attaching process. The electronic structure  44  can include printed portions that are printed using conductive ink and/or attached portions that are attached to the substrate  42 . If printed, the electronic structure  44  can be printed using transparent conductive ink and/or with colored conductive ink.  
         [0025]     The electronic structure  44  can be any suitable electronic structure. In one embodiment shown in  FIGS. 3-8A , the electronic structure  44  includes a printed RFID antenna  50  and an attached RFID IC  52 . The RFID IC  52  may be attached to the substrate  42  and/or the antenna  50 , for example, with a conductive adhesive  56 . The graphic art printing layer  46  is printed onto the substrate  42 .  
         [0026]     With continued reference now to  FIG. 4 , the electronic assembly  40  will be described in greater detail. The antenna  50  of the electronic structure  44  includes a pair of antenna attachment points  50   a ,  50   b  printed onto a first surface  58  of the substrate  42 . The RFID IC  52  is attached to the pair of antenna attachment points  50   a ,  50   b  with the conductive adhesive  56 . The protective layer  48  is attached to the antenna  50  and presents a substantially planar outer surface  60 . A gap  64  having a length L 1  is defined in the protective layer  48  for accommodating a length L 2  of the RFID IC  52 .  
         [0027]     The protective layer  48  according to some embodiments comprises an adhesive sheet  66  and a release liner  70 . The adhesive sheet  66  is attached to the antenna  50  and the release liner  70  is attached to the adhesive sheet  66 . In one form, the adhesive sheet  66  comprises a pressure sensitive adhesive. The adhesive sheet  66  may be printed onto the antenna  50  and/or substrate  42 . Alternatively, the protective layer  48  may comprise double sided tape. Still other variations are contemplated. As can be appreciated, the release liner  70  may be selectively removed from the adhesive sheet  66 . Then, the adhesive sheet  66  is attached to an object, such as a package or product  72  ( FIG. 6 ).  
         [0028]     The protective layer  48  defines a first thickness T 1  from an outer surface of the antenna  50  to the outer surface  60  of the protective layer  48 . The RFID IC  52  defines a second thickness T 2  that is preferably less than the first thickness T 1 . The RFID IC  52  lies in a protected area that is recessed relative to the protective layer  48 . As a result, stress and/or strain is reduced and/or eliminated on the electronic structure  44  and the electronic assembly  40 . In addition, while the adhesive layer  66  is shown to be approximately one-half the thickness of the release liner  70 , any suitable proportions may be implemented. Moreover, those skilled in the art will appreciate that the protective layer  48  may comprise the adhesive layer  66  exclusively.  
         [0029]     With continued reference to  FIG. 4  and further reference to  FIGS. 5 and 6 , installation of the electronic assembly  40  onto a surface  80  of the object  72  will now be described. At the outset, the release liner  70  is removed from the adhesive sheet  66  as shown in  FIG. 5 . Next, the adhesive sheet  66  is pressed onto the surface  80  of the object  72  as shown in  FIG. 6 . The RFID IC  52  is protected between the substrate  42  and the destination object  72 . The antenna  50  is shown deflected partially into the substrate  42   FIG. 6 . In the installed position, the graphics layer  46  is presented in a substantially planar manner.  
         [0030]     Referring now to  FIG. 7 , an automated manufacturing process  86  of the electronic assemblies  40  is shown. First electrical components  92  are printed and/or attached on a first surface  94  of a printing web  90 . A graphics layer  96  may be printed on a second surface  98  of the printing web  90 . In some embodiments, the first electrical components  92  define the first and second antenna attachment points  50   a  and  50   b . In  FIG. 7 , four antennas  50  are printed across the printing web  90 . However, additional and/or fewer antennas  50  can be printed if desired.  
         [0031]     The protective layer  48  and the second electrical components  100  are then attached. The protective layer  48  may include the adhesive sheet  66  and release liner  70  (as shown), which are located onto the respective first electrical components  92  such that respective passages  66 P and  70 P align to create a common passage P. As was described above, the adhesive sheet  66  may be pressure sensitive adhesive that is applied in any suitable manner and then the release liner  70  is applied over the pressure sensitive adhesive. Kiss cutting that is registered to where the chip is located can also be performed. Alternatively, double-sided tape can be used. The second electrical components  100  are located through the common passages P in the protective layer  48  and are attached to the first electrical components  92 . In some embodiments the second electrical components  100  include a series of ICs that are inserted through the common passages P and attached across antenna attachment points  50   a ,  50   b.    
         [0032]     The second electrical components  100  may be attached to the first electrical components  92  by conductive adhesive (such as adhesive  56 , illustrated in  FIG. 4 ). The conductive adhesive may be applied to adjacent sides of each antenna attachment points  50   a ,  50   b  ( FIG. 4 ) before the application of the RFID ICs  52 . In some embodiments, conductive adhesive may be applied to the second electrical component  100  instead of and/or in addition to the first electrical component  92 . The second electrical components  100  to be applied to each component on the printing web  90  may come in bulk on a roll or a web.  
         [0033]     Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the current invention can be implemented in a variety of forms. For example while the protective layer  48  has been described herein as having adhesive properties on an outer surface, the protective layer  48  may alternatively be void of adhesive properties. In this regard, the electronic assembly may be attached or otherwise retained in a secure position with an object by other methods while still maintaining the IC  52  in a nested relationship with the protective layer  48 . Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.