Patent Publication Number: US-2013233751-A1

Title: Recloseable blister package and method of use

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to packaging, and more particularly to blister packages used as point-of-sale product packaging. 
     A wide variety of products intended for retail sale are packaged in packaging that includes plastic components. One of the most common forms of plastic point-of-sale packages is a blister package. A typical blister package includes a shaped plastic blister that forms the main cavity of the package and a backer panel that closes the cavity. The backer panel is often sealed to the blister, for example, by adhesive to enclose the product within the cavity. The backer panel may be formed from paperboard, plastic, aluminum or other similar materials. Because of the use of a paperboard backer panel, a blister package has the potential to be a relatively low cost packaging solution. The amount of plastic used to contain the product is relatively small and the backer panel can be sized to provide ample space for printed content. 
     Another common form of plastic point-of-sale package is a clamshell package. A typical clamshell package includes a pair of formed plastic parts (often “halves”) that are joined along an integrated, living hinge. The clamshell parts can be closed about the hinge to entrap the product to be packaged. Clamshell packages vary dramatically in design and configuration. For example, some clamshell packages are sealed shut to protect the contents of the package until it is opened by the end consumer. With sealed clamshell packages, it is often necessary to at least partially destroy the package to gain access to the contents. This can, among other things, prove inconvenient and frustrating to the end consumer. In other applications, the clamshell is not sealed in the finished package. In a reclosable configuration, the clamshell can be formed with contours that permit the two clamshell parts to be friction interfitted in a way that holds the parts together in a closed configuration about the packaged contents. It is not uncommon to incorporate paper or paperboard inserts into clamshell packages. For example, information and other content can be printed on an insert that is enclosed within the clamshell. 
     One particularly innovative clamshell composite package is shown in U.S. Pat. No. 7,931,148 to Hansen et al for DOUBLE HINGE DISPLAY PACKAGE AND METHOD OF USE, issued Apr. 26, 2011, which is incorporated herein by reference in its entirety. In one embodiment, U.S. Pat. No. 7,931,148 discloses a hybrid package that includes a reclosable plastic clamshell that is combined with a pair of paperboard panels. The clamshell may include front and rear parts that are joined by two hinges, including a manufacturing hinge and an operating hinge. 
     Another innovative composite package is shown in U.S. application Ser. No. 13/228,541 to Hansen et al for RECLOSABLE DISPLAY PACKAGE AND METHOD OF USE, filed Sep. 9, 2011, which is incorporated herein by reference in its entirety. In one embodiment, this application discloses a package having a thermoformed plastic component that cooperates with a tray to define an article containing space. The peripheral lip of the tray and the flange portion of the plastic component may be sandwiched between a pair of panels to hold them in place with respect to one another. The panels define a large opening that provides communication between the tray and the door portion of the plastic component. This embodiment reduces the amount of plastic used in the package by replacing one-half of a clamshell with a tray. The tray can be manufactured in whole or in part from a fibrous recycled material. 
     SUMMARY OF THE INVENTION 
     The present invention provides a reclosable blister package with a blister and a backing that are joined to cooperatively form and article containing space. The blister includes a flange that is fixed to the backing. The flange includes a hinge that allows the blister to open and closed with respect to the backing. The blister includes one or more snap-locks that are configured to interfit with openings in the backing to selectively hold the blister in the closed position. 
     In one embodiment, the backing is formed of two panels. In this embodiment, the flange may be sandwiched between the panels. For example, one panel may include a slot that allows the flange to be fitted through the slotted panel so that it can be trapped between the panels. 
     In one embodiment, the backing is a single panel. In this embodiment, the flange may be joined to a surface of the backing. For example, the panel may include a slot that allows the flange to pass through the panel so that it can be secured to the panel on the side opposite the blister. 
     In one embodiment, the hinge is narrower that the flange. In this embodiment, the slot may include a flange insertion portion and a hinge seat. The hinge seat may be configured to closely receive the hinge. During assembly, the flange may be fed through the insertion portion and the hinge may be fitted into the hinge seat. The hinge and hinge slot may be configured sot that the hinge is exposed in the assembled package. 
     In one embodiment, the blister includes one or more locking protrusions configured to snap-lock with corresponding openings in a panel. The number and location of locking protrusions and locking openings may vary. In one embodiment, the blister includes a hang hole extension. In the embodiment, the locking protrusion or protrusions may be disposed on the hang hole extension. 
     In one embodiment, the blister includes a peripheral flange configured to engage the face of the backing when the blister is closed. The flange may extend from the blister at a shoulder. In this embodiment, the locking protrusion or protrusions may be disposed on the shoulder and may be configured to be fitted into aligned locking slots in the backing. In one embodiment, the blister and flange are generally rectangular and a locking protrusion may be located in each corner of the blister. 
     In one embodiment, the backing includes an aperture and may also include a transparent film filling the aperture. The film may allow the contents of the package to be viewed without opening the blister. 
     In one embodiment, the panels may be joined by a cohesive, such as a rubber cement or a latex-based cohesive. The cohesive allows the package to be easily assembled without expensive sealing equipment. Alternatively, the panels may be joined by other adhesives, such as heat activated adhesives. In applications that incorporate a cohesive, the flange of the plastic component may be specially shaped to facilitate use with cohesive. In one embodiment the flange includes “wings” that extend outwardly to increase the strength of the connection between the plastic component and the panels while maintaining a bond between the panels. In one embodiment, the hinge extends in a transverse direction across the plastic component and the wings extend in a transverse direction beyond opposite transverse ends of the hinge. The wings may be spaced from the hinge a sufficient distance to allow the panels to be joined together by the cohesive in the region between the hinge and the wings to resist removal of the wings out from between the panels. 
     In one embodiment, the package may include a hang hole and the blister may include an extension configured to reinforce the hang hole. In this embodiment, the hang hole may be located toward the top of the package and the extension may be shaped to extend above the hang hole to reinforce the panels against tearing initiated at the hang hole. The extension may be shaped to extend completely around the hang hole, if desired. 
     In another aspect of the invention, a method is provided for forming a reclosable blister package. The blister is a one-piece plastic component having a blister portion and a flange. The flange may include a hinge. In one embodiment, the method includes the steps of: (a) forming a blister with a flange having a living hinge; (b) forming a backing with a slot configured to closely receive the flange of the blister; (c) fitting the flange through the slot so that the flange is disposed one side of the backing while the hinge and blister are exposed on the opposite side; and (d) securing the flange on the opposite side of the panel. In one embodiment, the backing includes two panels and the method includes sandwiching the flange between the two panels. 
     The present invention provides a simple and inexpensive blister that can be easily opened and closed, for example, by a consumer interested in gaining access to the packaged article(s). For example, the package allows a potential customer to inspect the packaged article(s) at the point of sale. It also allows a customer to more easily access article(s) once purchased. In this way, the present invention provides the benefits of a clamshell package while using only about one half as much plastic. The locking protrusion or protrusions provide a simple mechanism for snap-locking the blister into the closed position. In some embodiments, an extension of the blister is used to define a hang hole and to interlock with the backing. In some embodiments, the assembly slot includes a hinge seat that can facilitate assembly by providing a simply mechanism for registering the blister with respect to the backing. The hinge seat may also improve the overall strength of the package. 
     These and other objects, advantages and features of the invention will be more readily understood and appreciated by reference to the detailed description of the invention and the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a package in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of the package in an open position. 
         FIG. 3  is a top plan view of the package. 
         FIG. 4  is a perspective view of the blister. 
         FIG. 5  is a top plan view of the blister. 
         FIG. 6  is a rear view of the blister package. 
         FIG. 7  is a front view of the blister. 
         FIG. 8  is a right side view of the blister. 
         FIG. 9A  is a side view of the blister package with a portion shown in section. 
         FIG. 9B  is enlarged view of Area A in  FIG. 9A . 
         FIG. 10  is top plan view of a first alternative blister. 
         FIG. 11  is top plan view of a second alternative blister. 
         FIG. 12  is top plan view of a third alternative blister. 
         FIG. 13  is a top plan view of the backing. 
         FIG. 14  is a top plan view of an alternative backing. 
         FIG. 15  is a perspective view of a package in accordance with an alternative embodiment. 
         FIG. 16  is a perspective view of the alternative package in an open position. 
         FIG. 17  is a top plan view of the alternative package. 
         FIG. 18  is a perspective view of the alternative blister. 
         FIG. 19  is a top plan view of the alternative blister. 
         FIG. 20  is a rear view of the alternative blister package. 
         FIG. 21  is a front view of the alternative blister. 
         FIG. 22  is a right side view of the alternative blister. 
         FIG. 23A  is a side view of the alternative blister package with a portion shown in section. 
         FIG. 23B  is enlarged view of Area A in  FIG. 23A . 
         FIG. 24  is a perspective view of a second alternative blister package. 
         FIG. 25  is a perspective view of the second alternative package in an open position. 
         FIG. 26  is a top plan view of the second alternative blister package. 
         FIG. 27  is a right side view of the second alternative blister package. 
         FIG. 28A  is a back view of a portion the second alternative blister package. 
         FIG. 28B  is an enlarged sectional view taken along line A-A of  FIG. 28A . 
         FIG. 29  is a top plan view of the blister of the second alternative blister package. 
         FIG. 30  is a top plan view of the backing of the second alternative blister package. 
     
    
    
     DETAILED DESCRIPTION OF CURRENT EMBODIMENTS 
     A reclosable blister package in accordance with an embodiment of the invention is shown in  FIGS. 1-3  and is generally designated  10 . The blister package  10  is designed to hold and display articles, for example, at the point of sale. The blister package  10  of  FIG. 1  generally includes a blister  12  and a backing  14 . In this embodiment, the blister  12  is a thermoformed plastic component and the backing  14  is a pair of paper board panels  16 ,  18  (See  FIGS. 13 and 14 ). In the illustrated embodiment, the blister  12  and the backing  14  cooperate to form a cavity  20  adapted to contain the packaged article(s) (not shown). The blister  12  includes a flange  22  that is fixedly secured to the backing  14 . The flange  22  includes a hinge  24  that allows the blister  12  to pivot between open and closed positions to provide selective access to the packaged article(s). In this embodiment, the flange  22  is secured between the panels  16 ,  18  to hold the blister  12  in place with respect to the backing  14 . The blister  12  includes one or more locking protrusions  38  that can be interfitted with one or more openings in the backing  14  to snap-lock the blister  12  in the closed position. The locking protrusions  38  may vary from application to application (See e.g.  FIGS. 5 ,  10 ,  11  and  19 ). The backing  14  may be a single paperboard component that is divided into panels  16 ,  18  by a fold line  26 . If desired, the panels  16 ,  18  may be sealed together using a cohesive (not shown) extending over the inner surfaces of the panels  16 ,  18 . When used, cohesive permits simple manual assembly of the blister package  10  without sealing equipment. 
     The present invention is described in connection with various alternative embodiments configured to provide a generally rectangular reclosable blister package. These embodiments are merely exemplary and the present invention is not limited to rectangular reclosable blister packages. To the contrary, the size, shape and configuration of the blister and the backing may vary from application to application, as desired. For example, the size and shape of the blister and the backing may vary to accommodate articles of different sizes and shapes, or to provide packaging with unique and distinctive aesthetic appearance. 
     Directional terms, such as “front,” “rear,” “vertical,” “horizontal,” “top,” “bottom,” “upper,” “lower,” “inside,” “inner,” “inwardly,” “outside,” “outer” and “outwardly,” are used to assist in describing the invention based on the orientation of the embodiments shown in the illustrations. The use of directional terms is merely an expedient to facilitate disclosure with reference to the illustrations and should not be interpreted to limit the invention to packages of any specific orientation(s). 
     As noted above, the blister package  10  generally includes a blister  12  and a backing  13 . The blister  12  is configured to be reclosable against the face of the backing  14 . In this way, the blister  12  and the backing  14  cooperatively form an article receiving space. In the illustrated embodiment, the blister  12  is a thermoformed plastic component formed from one piece of plastic (See  FIGS. 4-8 ). In the illustrated embodiment, the blister  12  includes a cavity portion  28  and a flange  22 . The cavity portion  28  is shaped to form a pocket, which, when moved into the closed position, cooperates with the backing  14  to create an article containing cavity  20 . In the illustrated embodiment, the blister  12  and the cavity portion  28  are generally rectangular. However, the blister  12  and the cavity portion  28  can be virtually any desired size and shape depending on the article(s) to be packaged or any other design or aesthetic considerations. For example, the blister  12  can alternatively be round, oval or essentially any other suitable shape. The cavity portion  28  can be shaped to snuggly receive the packaged article(s). For example, the cavity portion  28  may be formed to correspond with the interfacing contours of the packaged article(s) so that the article(s) can be seated within the blister  12 . The number of cavity portions may also vary from application to application, as desired. For example, a single blister may be formed with a plurality of discrete cavity portions, where each portions is configured to package a separate article or a separate collection of articles. 
     The blister  12  may include a peripheral lip  32  configured to engage the face of the backing  14  when the blister  12  is in the closed position. In the illustrated embodiment, the peripheral lip  32  extends around the periphery of the cavity portion  28 . The lip  32  of this embodiment is continuous and generally uniform in width, but may be discontinuous and may vary in width, if desired. In some applications, the lip  32  may be eliminated. 
     As noted above, the blister  12  is secured to the backing  14  by flange  22 . The flange  22  extends from an edge of the cavity portion  28  and includes a hinge  24  that allows the cavity portion  28  to pivot freely with respect to the flange  22 . In the illustrated embodiment, the cavity portion  28  is generally rectangular and the flange  22  extends from the bottom of the cavity portion  28 . The size, shape and configuration of the flange  22  may vary from application to application. The flange  22  may be secured to the backing  14  in essentially any suitable matter. In the illustrated embodiment, the flange  22  is trapped between the panels  16 ,  18 . In this embodiment, the panels  16  and  18  are joined face-to-face by a cohesive. Because the cohesive adheres predominantly only to itself, the flange  22  may be shaped to improve the cohesive interconnection of the various components. For example, in the illustrated embodiment, flange  22  includes extensions  30  that extend outwardly from opposite ends of the flange  22  to provide structure than can be entrapped between the cohesively adhered panels  16  and  18 . In the illustrated embodiment, the overall width of the flange  22 , including extensions  30 , is narrower than the overall width of the backing  14  in the region of the flange  22  by an amount sufficient to provide adequate adhesion between the panels  16 ,  18  along the perimeter of the package  10 . The amount of surface area in contact between panel  16  and panel  18  will affect the strength of the adhesion between the panels. By increasing the area of contact, the bond between the panels  16 ,  18  can be increased. This will not only help to hold the panels  16 ,  18  together, but if the area of contact is increased in the path along which the flange  22  must be moved to remove it from between the panels, then it will also help to retain the flange  22 . In use, the size, shape and configuration of the flange  22  and the extensions  30  may vary from application to application to provide an appropriate balance between various factors, such as strength of the flange  22 , retention of the flange  22  between the panels  16 ,  18 , and adhesion between the panels  16 ,  18 . 
     The flange  22  is adjoined to the cavity portion  28  by hinge  24 . The hinge  24  can be essentially any structure that allows the cavity portion  28  to pivot with respect to the flange  22  between open and closed positions. In the illustrated embodiment, the hinge  24  is a living hinge formed integrally with blister  12 . For example, the hinge  24  may be a square hinge (as shown) or other type of hinge form by shaping the plastic material. Despite the name, the square hinge  24  need not be “square”, but rather can be a ridge or bump or protrusion of essentially any cross-sectional shape (such as square, rectangular, round or triangular) formed in the plastic component. As a result of its shape, the square hinge  24  may reinforce the blister  12  in the transverse direction. More specifically, the square hinge  24  may be generally rigid in the traverse direction (e.g. along the length of the hinge), while still allowing the blister  12  to easily pivot between the open and closed positions. The square hinge may be facilitated by trim lines, die cuts, or other mechanisms generally know in the art. Alternatively, the hinge  24  can be a line of weakening extending transversely across the material of the plastic component, such that the cavity portion  28  and the flange  22  are capable of folding at the line of weakening. The line of weakening can include, for example, include a fold line, a score line, a line of reduced thickness or a line of perforations. In use, the hinge  24  may allow the cavity portion  28  to pivot away from the backing  14  as far as necessary to create an opening through which article(s) can be inserted into or removed from the package  10 . As shown in  FIG. 1 , the hinge  24  may be exposed (e.g. not beneath the front panel  16  to allow the blister  12  to be opened and closed repeatedly without interference from the front panel  16 . The hinge may alternatively be located between the panels  16 ,  18 , if desired. 
     In the embodiment of  FIGS. 1-3 , the flange  22  and hinge  24  extend continuously across the blister  12 . Alternatively, the flange and hinge may be discontinuous. For example, the blister  212  may include a flange that is divided into separate first and second flanges  222   a - b , each with an integrated hinge  224   a - b  (See  FIG. 12 ). As shown in  FIG. 12 , each flange  222   a - b  may include lateral extensions  230  to provide an improved connection with the panel or panels. 
     As noted above, the blister  12  is configured to selectively interlock with the backing  14  to hold the blister  12  in the closed position. The structure for interlocking the blister  12  and the backing  14  may vary from application to application. For example, in the embodiment of  FIGS. 1-14 , the blister  12  includes an upper extension  36  that includes locking protrusions  38  that snap-fit with an opening  40  in the backing  14  (See e.g.  FIGS. 6 ,  9 A and  9 B). As another example, in the embodiment of  FIGS. 15-23 , the blister  12 ′ includes locking protrusions  38 ′ that extend from the periphery of the cavity portion  28 ′ and snap-fit with openings  40 ′ in the backing  14 ′ (See e.g.  FIGS. 20 ,  23 A and  23 B). 
     Referring now to  FIGS. 4 ,  5  and  8 , the blister package  10  includes an upper extension  36  that extends from the top of the cavity portion  28  opposite the flange  22 . In this embodiment, the upper extension  36  is centered on the cavity portion  28  and is substantially narrower the cavity portion  28 . The illustrated upper extension  36  extends to the top of the backing  14  and defines a hang hole  42 . The illustrated hang hole  42  is merely exemplary. The size, shape and configuration of the hang hole  42  may vary from application to application as desired. The extension  36  may include a tab  44  that provides a structure for grabbing the extension  36  to pull it open. In the illustrated embodiment, the tab  44  extends from the top center of the extension beyond the upper edge of the backing  14 . However, the location of the tab  44  may vary from application to application. In some applications, the extension  36  and tab  44  may be configured to remain within the periphery of the backing  14 . Although not shown, the tab  44  may be bent out of the plane of the extension  36  to extend at angle away from the backing  14 , if desired. The tab  44  may be sized and shaped to provide sufficient gripping surface for a user to overcome the resistance to opening created by the interaction of the structure that interlocks the blister  12  and the backing  14 . For example, the tab  44  can be sized so that it can be readily squeezed between a user&#39;s thumb and forefinger. As shown, the tab  44  may be positioned at the top center of the upper extension  36 , but the tab  44  may be positioned at other locations, such as at essentially any desired location on the upper extension  36  or the lip  32 . 
     In the embodiment of  FIGS. 1-9 , the locking protrusions  38  are disposed about the hang hole  42 . Although the number and location of locking protrusions  38  may vary, in this embodiment, the extension  36  includes two semicircular locking protrusions  38  arranged on opposite sides of the hang hole  42 . The locking protrusions  38  are formed with a reverse draft that allows them to snap-lock into engagement with the backing  14  (See  FIGS. 9A and 9B ). The size, shape and configuration of the locking protrusions  38  may vary from application to application. For example, in the alternative blister  312  of  FIG. 10 , the locking protrusions  338  may be disposed above and below the hang hole  342  rather than on opposite sides. As another example, in the alternative blister  412  of  FIG. 11 , the extension  436  may include a single locking protrusion  438  that forms a closed loop around the hang hole  442 . In these embodiments, the backing defines a single opening  40  that is aligned with the locking protrusions  38  and the hang hole  42  (described in more detail below). 
     As noted above, the cavity portion  28  and the flange  22  can be integrally formed. The integrally formed blister  12  can be thermoformed or formed in any other suitable manufacturing process in one piece, such as from a single, one-sided die. Alternatively, the cavity portion  28  and the flange  22  may separately formed and joined by a component that forms the hinge  24 . For example, the cavity portion  28  and the flange  22  may be separately formed and joined by a tape (not shown) or other form of flexible material. Although the cavity portion  28  of the illustrated embodiment is generally rectangular, the size, shape and configuration of the cavity portion  28  vary from application to application as desired. Similarly, the number of cavity portions may also vary from application to application, as desired. For example, a single blister may be formed with a plurality of discrete cavity portions, where each portions is configured to package a separate article or a separate collection of articles. 
     The blister  12  may be injection molded or thermoformed, and is typically constructed from polyvinyl chloride (PVC) or polyethylene terephthalate (PET) or some other polymer. Although the material is typically transparent, translucent or clear, the stock may also be opaque, clouded or tinted any suitable color in some applications. The blister  12  will vary in thickness from application to application. For standard applications, the blister  12  is likely to have a thickness ranging between 12 and 30 gauge (i.e., 12 to 30 thousands of an inch). 
     As noted above, the backing  14  of the illustrated embodiment includes two panels  16 ,  18  that are joined face-to-face to form a structure for closing the rear of the blister  12  and entrapping the flange  22  (See  FIG. 13 ). The panels  16  and  18  also provide surface area that can receive printed material, such as text and images. In the illustrated embodiment, the backing  14  includes a front panel  16  and a rear panel  18 . In the assembled package  10 , the front and rear panels  16 ,  18  of this embodiment are joined together around the entire peripheral the flange  22 . The front and rear panels  16 ,  18  may be secured together and/or to the flange  22  in any suitable manner, including adhesives known in the art. For example, the panels  16 ,  18  can be secured with a rubber or latex cohesive. As an alternative to cohesive, the panels  16 ,  18  may be joined face-to-face by any suitable adhesive, connector or fastener may (alone or in combination) be used to join the panels  16 ,  18  and the flange  22 . The panels  16 ,  18  can be any desired size and shape depending on any number of relevant factors, such as desired aesthetics and the characteristics of the article(s) to be packaged (e.g. number, size, shape and weight). The backing  14  can be constructed out of paperboard material. However, other materials commonly known in the art, such as plastic, may also be used to form the door panel and tray panel. In the illustrated embodiment, the front and rear panels  16 ,  18  are integrally formed from a single piece of paperboard. For example, as shown in  FIG. 13 , the panels  16 ,  18  are joined together along a fold line  26  located along the top of each panel  16 ,  18 . The fold line  26  may be a score line, a partial cut line, a row of perforations or the like. In the embodiment of  FIG. 13 , the fold line  26  forms the upper peripheral edge of the package  10  ( FIG. 4 ), but could be along any edge of the package  10 . As another example, shown in  FIG. 14 , the backing  114  includes panels  116 ,  118  that are joined together along a fold line  126  located along a side of the panels  116 ,  118 . In another alternative embodiment (not shown), the panels may be manufactured separately from one another. Although the backing  14  of the illustrated embodiment includes front and rear panels  16 ,  18 , the backing may alternatively include only a single panel (e.g. front panel  16 ). In embodiments with only a single panel, the flange  22  may be secured to the back side of the panel, for example, by cement, adhesive or mechanical fasteners. 
     In the illustrated embodiment, the front panel  16  defines a blister slot  48  configured to allow the flange  22  to be fitted though the front panel  16 . In the illustrated embodiment, the blister slot  48  includes a flange insertion portion  60  and a hinge seat  62 . The flange insertion portion  60  may extend transversely across the front panel  16  and may be of sufficient length and width to allow the flange  22  to pass through the front panel  16 . As shown, the overall width of the flange insertion portion  60  may coincide with the width of the flange  22 , including lateral extensions  30 . In this embodiment, the hinge seat  62  is in communication with the flange insertion portion  60  so that, during assembly, the flange  22  can be fitted through the front panel  16  and then moved down until the hinge  24  is fitted into the hinge seat  62 . In this embodiment, the width of the hinge seat  62  is slightly larger than the width of the hinge  24  and significantly narrower than the full width of the flange  22 . In this way, the hinge seat  62  is configured to provide a seat capable of closely receiving the hinge  24  to locate the blister  12  with respect to the backing  14 . The depth of the hinge seat  62  (e.g. the distance between the hinge seat  62  and the flange insertion slot  60 ) may vary from application to application. For example, the hinge seat  62  may be substantially deeper to provide additional spacing between the seated hinge  24  and the flange insertion portion  60 . In one embodiment, this means moving the flange insertion slot  60  farther up the card away form the hinge seat  62 . In some applications, this may reduce the likelihood of the flange  22  being pulled out from between the panels  16 ,  18 . 
     In the embodiment of  FIG. 14 , the panels  16 ,  18  also include an opening  40  configured to receive the locking protrusions  38 . The size, shape and configuration of the opening  40  are selected to correspond with the locking protrusions  38  so that the locking protrusions  38  can be snap-fitted into the opening  40 . As shown, the opening  40  extends through both panels  16 ,  18 , thereby allowing the locking protrusions  38  to be pushed entirely through the backing  14 . In this embodiment, the opening  40  is generally oval in shape and is positioned to not only receive the locking protrusions  38 , but also to provide a through hole coincident with the hang hole  42  in the blister  12 . In the illustrated embodiment, the backing  14  includes a single opening that provides a through-hole for the hang hole  42  and is capable of receiving both locking protrusions  38 . Alternatively, the backing  14  may include separate openings (not shown), for example, one opening for the hang hole  42  and a separate opening for each locking protrusion  38 . 
     Although the panels  16 ,  18  of the illustrated embodiment are generally rectangular, they may vary from application to application as desired. For example, the general shape of the panels  16 ,  18  may vary depending on the shape of the article(s) to be packaged, the shape of the blister  12  and/or on the desired package aesthetics. 
     Assembly of the blister package  10  of  FIG. 9  will now be described. In this embodiment, the blister  12  and panels  16 ,  18  are separately manufactured. These components may be manufactured using conventional techniques and apparatus. For example, the blister  12  can be thermoformed using a conventional negative mold, and the backing  14  can be die-cut from the desired paperboard stock. The backing  14  includes front panel  16  and rear panel  18  joined along fold line  26 . The flange  22  of the blister  12  may be inserted through the blister slot  48 . More specifically, the flange  22  may be inserted through the flange insertion portion  60  so that the flange  22  is primarily disposed on the inside of the front panel  16  and the hinge  23  and the cavity portion  28  are disposed on the outside of the front panel  16 . The flange  22  is then moved down into the blister opening  48  to position the hinge  24  in the hinge seat  62 . Because the hinge seat  62  coincides in width with the hinge  24 . This action will properly locate the blister  12  with respect to the backing  14 . 
     After the blister  12  is properly seated in the front panel  16 , the panels  16 ,  18  may be closed to sandwich the flange  22 . In the illustrated embodiment, the front panel  16  and rear panel  18  are joined along fold line  26  and the backing  14  is closed by pivoting the front panel  16  and rear panel  18  together about the fold line  26 . The front panel  16  and rear panel  18  may be joined together by cement, adhesive or other mechanisms. In the illustrated embodiment, the entire inner surfaces of the front panel  16  and rear panel  18  are coated with a cohesive. When the inner surfaces of the two panels  16 ,  18  are brought into contact, they adhere to one another. The adhesion between the panels  16 ,  18  also holds the flange  22 , including lateral extensions  30  to resist removal of the flange  22  from between the panels  16 ,  18 . Alternatively, the panels  16 ,  18  may be joined by other cements or adhesives, such as heat activated adhesive, heat seal coating, standard glue, hot melt glue, single-sided tape, double-sided tape or an RF adhesive. If it is desirable to use single-sided tape, one method of doing so may be to tape the flange  22  to one of the panels  16 ,  18 , and to tape the panels  16 ,  18  together with tape applied around the outside of the panels  16 ,  18 . As another alternative (or in addition), the panels  16 ,  18  may be joined by mechanical structures, such as staples, rivets, grommets, push-lock pins or crimping. With embodiments that include a mechanical structure, the mechanical structure may extend through the flange  22  to mechanically secure the flange  22  with respect to one or both of the panels  16 ,  18 . For example, the blister  12  may be secured by a staple extending through the flange  22  and one or both of the panels  16 ,  18 . Additional methods for joining the panels  16 ,  18  may be available with specific panel materials. For example, if the panels  16 ,  18  are manufactured from plastic, they may be joined using ultrasonic or RF methods. Some alternative adhesives may adhere directly to the flange  22  and may therefore improve the bond between the panels  16 ,  18  and the flange portion  22 . Although the entire inner surfaces of the panels  16 ,  18  are covered with adhesive in the illustrated embodiment, they may be partially coated in some applications. For example, in some applications, adhesive may be applied only along the peripheral edges of the panels  16 ,  18  or in select locations as desired to provide a suitable bond between the panels  16 ,  18  and flange  22 . 
     After the panels  16 ,  18  have been joined together, the blister  12  may be moved into the closed position. In this embodiment, the blister  12  may be pivoted about hinge  24  until the cavity portion  28  engages the face of the front panel  16  and the locking protrusions  38  are fitted through opening  40  in the backing  14 . More specifically, the cavity portion  28  can be pivoted into engagement with the front panel  16  and the extension  36  can be pressed toward the backing  14  until the locking protrusions  38  are snap-fitted into the opening  40 . The interaction between the locking protrusions  38  and the opening  40  provides a snap lock that helps to hold the cavity portion  28  in the closed position (See  FIGS. 6 ,  9 A and  9 B). In this embodiment, the peripheral lip  32  of the cavity portion  28  engages the outer surface of front panel  16  when the cavity portion  28  is snap-locked in the closed position (See e.g.  FIG. 6 ). 
     A blister package  10 ′ in accordance with an alternative embodiment of the present invention is shown in  FIGS. 15-23 . This alternative blister package  10 ′ is essentially identical to blister package  10 , except as expressly described. In this embodiment, the upper extension  36  is eliminated and the locking protrusions  38 ′ are disposed about the periphery of the cavity portion  28 ′. In this embodiment, the cavity portion  28 ′ includes a shoulder  70 ′ that provides a transition from the side wall  72 ′ to the peripheral lip  32 ′. The size, shape and configuration of the shoulder  70 ′ may vary from application to application. However, in the illustrated embodiment, the shoulder  70 ′ extends entirely around the cavity portion  28 ′ and is configured to engage the face of front panel  16 ′ when the blister  12 ′ is in the closed position. Although continuous in the illustrated embodiment, the shoulder  70 ′ may be discontinuous, if desired. In the illustrated embodiment, the shoulder  70 ′ includes four locking protrusions  38 ′ that snap fit with corresponding openings  40 ′ in the backing  14 ′ (described below) to hold the cavity portion  28  in the closed position. The locking protrusions  38 ′ of this embodiment are extensions from shoulder  70 ′ that have a reverse draft and are configured to snap-lock with the backing  14 . In the illustrated embodiment, the locking protrusions  38 ′ include four protrusions generally positioned at the corners of the shoulder  70 ′. The number of locking protrusions  38 ′ may vary and they may be positioned in essentially any desired location on the shoulder  70 ′. The characteristics of the locking protrusions  38 ′, such as the number, location, shape and/or length of the snap elements, may be varied to provide the desired to characteristics in the snap-fit between the blister  12 ′ and the backing  14 ′. For example, longer or shorter snap elements  46  may vary the overall force required to snap-fit the blister  12 ′ into the closed position. Further, the leading and closing edges of the locking protrusions  38 ′ may be non-planar to provide some control over the interaction between the locking protrusions  38 ′ and the blister  12 ′. For example, the leading edge of the locking protrusions  38 ′ can be ramped to provide less resistance when snapping them into engagement with the backing  14 ′. As another example, the trailing edge of the locking protrusions  38 ′ can be squared to provide increased resistance to opening of the blister  12 ′. Alternatively, or additionally, the characteristics of the interfacing portions of the backing  14 ′, such as size or shape, may be varied to control the force required to operate the snap-fitting interaction of the blister  12  and backing  14 . For example, the force required to open and close the blister  12 ′ may be varied by increasing or decreasing the closeness of the fit between the locking protrusions  38 ′ and the backing  14 ′, or by varying the thickness or characteristic of material of the panels  16 ,  18 . 
     Optionally, the peripheral lip  32 ′ can include a tab  34 ′ extending outward from the peripheral lip  32 ′. The tab  34 ′ can be pulled by a user to swing the cavity portion  28 ′ away from the backing  14 ′ to open the package  10 ′. The tab  34 ′ may be sized and shaped to provide sufficient gripping surface for a user to overcome the resistance to opening created by the interaction of the structure that interlocks the blister  12 ′ and the backing  14 ′. For example, the tab  34 ′ can be sized so that it can be readily squeezed between a user&#39;s thumb and forefinger. As shown, the tab  34 ′ may be positioned at a corner of the lip  32 ′, but the tab  34 ′ may be positioned at any desired location on the lip  32 ′. As shown, the tab  34 ′ may be bent out of the plane of the lip  32 ′ to extend at angle away from the backing  14 ′, if desired. For example, in this embodiment, the tab  34 ′ includes a small nub  35 ′ that keeps the tab  34 ′ away from the front panel  16 ′. 
     In this embodiment, the panels  16 ′,  18 ′ are provided with openings  40 ′ configured to receive the locking protrusions  38 ′ on the shoulder  70 ′ of the cavity portion  28 ′. In this embodiment, the locking protrusions  38 ′ and openings  40 ′ may be configured so that the snap-lock occurs at the corners of the cavity portion  28 ′, which may provide a stiffer and more stable interaction between the cavity portion  28 ′ and backing  14 ′. As with blister package  10 , the details of the locking protrusions  38 ′ and openings  40 ′ can be varied to adjust the characteristics of the interlock. For example, the number, size and/or location of locking protrusions  38 ′ and openings  40 ′ may be varied. As another example, the shape of the leading and trailing edges of the locking protrusion  38 ′ may be varied. 
     In this embodiment, the backing  14 ′ may include a hang hole  42 ′ that allows the package  10  to be easily hung, for example, from a display hook at the point of sale. The hang hole  42 ′ may vary in size, shape, configuration and location, or it may be eliminated when unnecessary. In this embodiment, the hang hole  42 ′ is defined by separate openings in the panels  16 ′,  18 ′. These openings align to form the hang hole  42 ′ when the backing  14 ′ is closed. 
     Another alternative blister  512  package is shown in  FIGS. 24-30 . In this embodiment, the blister package  510  generally includes a blister  512  and a backing  514 , and is generally identical to blister package  10 , except as otherwise described. As shown in  FIGS. 24 and 25 , the blister  512  is capable of being moved between open and closed positions. The blister  512  includes an upper extension  536  having a locking protrusion  538  that extends around the periphery of the hange hole  542 . As with blister package  10 , the locking protrusion  538  is interfitted with the backing  514  to selectively hold the blister  512  in the closed position (See  FIGS. 27 ,  28 A and  28 B). As perhaps best shown in  FIG. 26 , the upper extension  536  may include a tab  534  extending beyond the upper edge of the backing  514  (as shown) or it may be fully contained within the periphery of the backing  514 . Although shown as flat, the tab  534  may be bent away from the backing  514  to make it easier to grasp. 
     In this embodiment, the hang hole  542  may include a somewhat triangular shape to accommodate the peripheral locking protrusion  538 . The size and shape of the hang hole  542  and the surrounding locking protrusion  538  may vary from application to application, as desired. As perhaps best shown in  FIG. 28B , the locking protrusion  538  may include a reverse draft to create a snap-lock fit with the backing. In the illustrated embodiment, the reverse draft extends at about 87 degrees with respect to the face of the extension portion  536 . The amount of reverse draft may, however, vary from application to application. If desired, the amount of reverse draft may vary along the locking protrusion. The reverse draft need not extend around the entire locking protrusion  538 , but may instead extend through only one or more portions of the locking protrusion  538 . For example, in the illustrated embodiment, the left side  537  and right side  539  of the locking protrusion  538  include reverse draft (See e.g.  FIGS. 28A ,  28 B and  29 ). More specifically, in the illustrated embodiment, the reverse draft extends only through the curved regions on the left and right sides  537 ,  539  of the locking protrusion  538 . 
     As perhaps best shown in  FIG. 29 , the blister  512  may include a flange  522  and a hinge  524 . The flange  522  may includes lateral extensions  530  that extend from opposite ends beyond the hinge  524 . The lateral extensions  530  may be rounded (as shown), but their size and shape may vary from application to application. 
     This alternative blister  512  may be used with a backing  514  having an opening  540  that corresponds in size and shape with the locking protrusion  538 . In this embodiment, the backing  514  includes a front panel  516  and a rear panel  518  that are joined at a fold line  526  (See  FIG. 30 ). The panels  514 ,  516  may be joined along different edges or may be separate components, if desired. As with blister package  10 , the backing  514  defines a blister slot  548  with a flange insertion portion  560  and a hinge seat  562 . 
     The blister packages  10 ,  10 ′ and  510  may be provided with other package features, as desired, such as functional and/or aesthetic features selected to tailor the package for specific applications. For example, the blister packages  10 ,  10 ′ and  510  may be provided with a foot to help it stand upright, a “touch and feel” hole that allows a user to touch and feel the packaged article(s) or any of a wide range of features that might be provided for branding purposes. As another example, a window may be formed through the backing to allow viewing of the package article(s). The window may be filled with a transparent film to allow viewing while protecting the article(s). 
     In another aspect, the present invention provides a method for forming a package, such as the blister package  10  described above. The method includes the steps of: (a) forming a blister  12  with a cavity portion  28 , a flange  22  and a hinge  24 ; (b) forming a front panel  16  with a blister slot  48  having a flange insertion portion  60  and hinge seat  62 ; (c) forming a rear panel  18 ; (d) inserting the flange  22  into the blister slot  48  so that the flange  22  is disposed on the inside of the front panel  16  and the hinge  24  and cavity portion  28  are disposed on the outside of the front panel  16 ; (e) closing the front panel  16  and rear panel  18  about the flange  22 ; (f) closing the blister  12  the door portion  18  and tray  20  cooperatively defining an article containing cavity and (h) selectively pivoting the door portion  18  about the hinge  14  to open and close the package  10 . 
     In one embodiment, the step of forming the plastic component  12  can include placing a piece of sheet stock in a mold and thermoforming the clamshell. The molding or thermoforming step can include forming cavity portion  28  and a flange  22  with a hinge  24 . The flange  22  may be formed with lateral extensions  30  that extend beyond the hinge  24 . In one embodiment, this step can also include (a) forming the blister  12  with an upper extension  60  that includes one or more locking protrusions  38  configured to snap into engagement within an opening in the backing  14 . In an alternative embodiment, this step can also include (a) forming the cavity portion  28 ′ with a shoulder  70 ′ that includes locking protrusions  38 ′ configured to snap into engagement with openings  40 ′ in the backing  14 ′. The cavity portion  28 ′ may be rectangular and the shoulder  70 ′ may include four locking protrusions  38 ′ at or near the corners. 
     Optionally, the step of joining the front panel  16  and the rear panel  18  may include securing them together using a cohesive. A layer of cohesive may be applied to the inside surfaces of each of the front panel  16  and the rear panel  18 . The inside surfaces of the two panels  16 ,  18  may be closed against each other to bring the layers of cohesive into contact, thereby joining the panels. 
     The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.