ES2965758T3 - Microwave heating tray - Google Patents

Abstract

A tray for heating, browning and/or browning a food in a microwave oven comprises a substantially flat base, a platform extending upwardly from the base and a microwave energy interactive element covering at least a portion of the platform. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Microwave heating tray

TECHNICAL FIELD

The present invention relates to various trays for heating or cooking food in a microwave oven. In particular, the invention relates to various trays for heating or cooking a food in a microwave oven, where the food has an irregular surface.

BACKGROUND

Microwave ovens provide a convenient means of heating a variety of foods, including numerous dough-based and potato-based frozen convenience foods. Unfortunately, in many cases, these foods tend to curl, bulge, or become disfigured during the freezing process rather than remaining in their original shape. As a result, many microwave-powered interactive packages currently available cannot provide sufficient contact with the food surface to provide the desired balance of comprehensive heating with a crispy, golden exterior surface. Therefore, there is a need for improved trays that provide the desired degree of heating, browning and/or crispness of a food having a contoured or irregular surface.

US 5,519,195 A and US 4,831,224 already show microwave heating trays with a substantially flat base and a raised heating surface that is interrupted by channels/parts extending to the base. However, these microwave heating trays still leave room for improvement to allow for the provision of a more specifically desired degree of heating, browning and/or crispness of a food having a contoured or irregular surface.

SUMMARY

The present invention is directed to various heating trays according to independent claim 1 and the claims that are dependent thereon.

The various constructions may include one or more characteristic features that enhance microwave heating, browning, and/or crispiness of a food. The various constructions may also include one or more characteristic features that conform to the contours of a food having an irregular surface, for example, a domed or curved surface. For example, various trays include one or more raised portions that bring microwave-enhancing features closer to the surface of the food. In some cases, such raised portions may be shaped, sized and/or configured to create the visual appearance of grill marks. Furthermore, the various trays include one or more characteristic features that allow the humidity generated during the food heating procedure to be eliminated by ventilation, thus also enhancing the golden color and/or crispiness. For example, the construction includes one or more ventilation channels extending along at least a portion of the raised portions.

The raising patterns, the space between the raised parts, the height of the raised parts, and the width and depth of the spaces between them can be selected based on the type of food to be heated and the desired cooking effect. For example, more or fewer raised portions may be provided, for example, depending on the degree of unevenness of the surface of the food to be browned or crisped, the moisture content of the food, the thickness of the food, characteristics of the food ( for example, fat content) and the surface area occupied by the food.

Additionally, the construction may include one or more portions with depressions (as seen from one side of the construction) corresponding to the raised portion on the other side of the construction. Where such depression portions are at the bottom of a construction that, in use, are adjacent to the bottom portion of a microwave oven, such depressions may provide an insulating air space that reduces heat loss from the interactive element. with microwave energy to the base of the microwave oven and also enhances the heating, golden color and/or crispiness of the food.

The raised portions may be formed using any suitable procedure or technique. In one aspect, the contours can be formed using a mechanical and/or thermal pressing process. In such a procedure, a preform is typically cut to the desired size and shape and placed in a forming mold or die with male and female sides. The male and female sides of the die are brought together, thereby applying pressure to the preform and deforming the preform to create the desired pattern of contours.

Additional aspects, characteristic features and advantages of the present invention will become apparent from the following description of some exemplary microwave heating constructions/trays.

DESCRIPTION

In what follows, various aspects of the invention can be illustrated. Furthermore, although several different exemplary aspects, implementations and embodiments of the various inventions are provided, numerous interrelationships between, combinations thereof and modifications of the various inventions, aspects, implementations and embodiments of the inventions are hereby contemplated. .

A first exemplary construction, in this example, a disc or tray is substantially circular in conformation and is substantially symmetrical along a longitudinal center line and a transverse center line. However, numerous other conformations and configurations are contemplated hereby. For example, the tray may have a triangular, rectangular, square, hexagonal or any other regular and irregular shape. Additionally, the tray may include no lines of symmetry, a single line of symmetry, or multiple lines of symmetry.

The tray includes a somewhat flat peripheral base or edge and a pair of opposite raised platforms or parts that serve as surfaces for receiving one or more foodstuffs thereon. The raised parts are separated by a recess that is substantially within the same plane as the edge. In this example, the recess is along the transverse centerline. However, the recess may have any other suitable shape or position, as necessary or desired for a particular application.

Each platform is substantially semicircular in shape, suitable for receiving, for example, half a panini or another sandwich thereon. Each platform includes a top face or surface (also called the "highest surface" and "warming surface"), a somewhat erect inner face, a somewhat erect outer face, and a pair of opposing corner faces. It will be understood that, in this and other aspects of the invention, the various faces are described as being individual surfaces or faces merely for purposes of simplicity and ease of description, and that said surfaces or faces may be substantially continuous and without having a boundary. defined between them. Furthermore, it will be understood that the platform may have any desired shape, and that numerous other regular and irregular shapes are contemplated hereby.

In this example, the inner face and outer face of each platform extend obliquely, sloping outward and downward, and tapering in height from the upper face toward the recess or edge, respectively. Likewise, the corner faces are inclined outward and downward from the upper face towards the recess and/or edge, so that the corner face has a generally rounded or convex shape. However, in this and other aspects, it is contemplated that the various faces defining the platform may be substantially vertical, or may taper inward and downward from the platform, if needed or desired for a particular application.

If desired, one or both platforms can be contoured to generally conform to the shape of a food. In this example, each platform is uniform in height when viewed along the longitudinal center line of the tray, and is curved or crowned when viewed along the inside face of the platform, so that the platform and, therefore, Therefore, the upper surface decreases in height from the longitudinal center line towards each of the corner faces. Such a tray may be, in particular, very suitable for use with foods that have a somewhat curved conformation, such as frozen dough-based foods (e.g. sandwiches, pizzas, etc.).

The tray can be characterized as having various heights, lengths and radii of curvature, each of which can be varied for a particular application. The dimensions of each platform may be substantially identical, so that the tray is substantially symmetrical along each side of the longitudinal centerline, or may differ, so that the tray is not symmetrical along each side of the longitudinal center line. Likewise, the dimensions of each platform may be substantially identical, so that the tray is substantially symmetrical along each side of the transverse centerline, or may differ, so that the tray is not symmetrical along each side. of the transverse center line.

If desired, any of the various trays of the invention may include characteristic features that alter the effect of microwave energy during heating or cooking of the food. For example, any of the trays may be formed partially from one or more microwave energy interactive elements (sometimes called "microwave interactive elements") that promote browning and/or crispness of a particular area of the food. , protect a particular area of the food from microwave energy to prevent overcooking, or transmit microwave energy toward or away from a particular area of the food. Each microwave interactive element comprises one or more microwave energy interactive materials or segments arranged in a particular configuration to absorb microwave energy, transmit microwave energy, reflect microwave energy or direct microwave energy, as necessary or desired for a construction of microwave heating and particular food.

The microwave interactive element may be supported on a microwave inactive or transparent substrate for ease of handling and/or to prevent contact between the microwave interactive material and the food, as will be discussed in more detail below. As a matter of convenience and not limitation, and although a microwave interactive element supported on a microwave transparent substrate is understood to include both microwave interactive and microwave inactive elements or components, such structures may be referred to herein as " microwave interactive bands".

In one example, the microwave interactive element may comprise a thin layer of microwave interactive material that tends to absorb microwave energy, thereby generating heat at the point of contact with a food. Such elements are often used to promote the browning and/or crispiness of the surface of a food. When supported on a film or other substrate, such an element may be referred to together with the substrate as a "susceptor film" or sometimes simply as a "susceptor."

For example, a microwave energy interactive element, e.g., a susceptor, may cover all or a portion of each platform, including all or a portion of the top surface, recess, interior face and/or corner faces of one or both platforms. A susceptor or other element interactive with microwave energy may also cover all or part of the outer face.

When the susceptor is supported on a polymeric film, it will be understood that the polymeric film substrate may cover additional portions or substantially all of the tray, with the microwave energy interactive element (i.e., the susceptor) being located between the substrate and the support component. particular tray in the desired location to heat, brown and/or crisp the food. In this way, a tray can be pressed or otherwise formed from a multilayer structure comprising the susceptor film bonded to the material used to form the tray.

To use the tray, one or more foods are typically placed on each platform and placed in a microwave oven. In a particular example, the food is a sandwich that has been separated into two sections, each including a piece of bread and one or more toppings in an "open face" configuration. In another particular example, the food is a pizza, which has been separated into, or provided as, two separate pieces, slices or portions. In yet another example, the food is a single food, for example, a pizza, that has not been divided into separate pieces, slices or portions. In one such example, the pizza may cover both platforms and the recess between them. Alternatively, it is contemplated that the tray may include a single platform having a generally circular shape to accommodate the circular pizza bulge. In this case, the platform may have an overall domed configuration, so that the height of the platform decreases in any direction from the center of the platform outward toward the base of the tray. Still alternatively, it is contemplated that the tray may include a plurality of platforms, each intended to receive one or more of a plurality of foods, or one or more parts of a plurality of foods, to be heated.

In any case, the food is placed on the heating surface of each platform with the surface to be browned and/or crisped, for example, the bread or pizza crust, adjacent to the tray. The contoured heating surface of the platform generally conforms to the contoured surface of the food, which is often prone to curling during the freezing process, and brings the susceptor closer to the surface of the food to be browned. and/or become crispy.

It should be noted that, with any of the numerous trays contemplated herein, the food or foods may be slightly larger than the respective platform and therefore the food may extend slightly beyond the "boundaries" of the surface. heating, in this example, the upper face. As the food thaws, any such portion of the food that extends beyond the heating surface may flex downward and come into close and/or intimate contact with the various erect faces of the platform. When a microwave energy interactive element, for example, a susceptor, covers said faces, the faces can serve as heating surfaces to enhance the browning and/or crispiness of the corresponding parts of the food.

As the microwave heating cycle continues, the susceptor converts the microwave energy into thermal energy, which is then transferred to the adjacent surface of the food. In this way, the golden color and/or crunchiness of the surface of the food can be enhanced. Additionally, the platforms keep the food in an elevated position from the base or turntable of the microwave oven, which reduces the amount of sensible heat transferred from the susceptor to the ambient environment of the microwave oven and further enhances the browning and/or the crunchiness.

Any of the numerous microwave interactive elements described herein or contemplated herein may be substantially continuous, that is, without substantial breaks or interruptions, or may be discontinuous, for example, by including one or more breaks or openings that transmit microwave energy through it. Breaks or openings can be sized and positioned to heat particular areas of the food selectively. The number, shape, size and location of said breaks or openings may vary for a particular application depending on the type of tray or other construction being formed, the food to be heated in or on it, the desired degree of protection, golden color and/or crispness, whether direct exposure to microwave energy is needed or desired to achieve uniform heating of the food, the need to regulate the temperature change of the food through direct heating, and whether and to what extent ventilation is needed.

It will be understood that the opening may be a physical opening or gap in the material used to form the construction, or it may be a non-physical "opening." A non-physical opening may be a portion of the tray that is inactive with microwave energy by deactivation or otherwise, or one that is otherwise transparent to microwave energy. Therefore, for example, the opening may be a part of the tray formed without a microwave active material or, alternatively, it may be a part of the tray formed with a microwave active material that has been deactivated. . Although both physical and non-physical openings allow food to be heated directly by microwave energy, a physical opening also provides a venting function to allow steam or other vapors to be released from the food.

Other examples of microwave energy interactive trays according to the invention include one or more discontinuities in the microwave energy interactive element. The various other exemplary trays explained below include characteristic features that are similar to the tray of the first example, except for noted variations and variations that will be understood by those skilled in the art.

In a second example, the microwave energy interactive element comprises a plurality of spaced susceptor stripes (shown by stippling) extending obliquely along the transverse centerline of the tray, with transparent or inactive areas. with microwaves between them. The stripes can have any width, orientation and configuration as desired. When used to heat a food, the microwave energy interactive stripes can form a corresponding plurality of darkened areas on the outer surface of the food. Such marks may resemble grill marks, such as with a parapanini grill.

In this and other aspects of the invention, it will be understood that the arrangement of the microwave energy interactive and microwave energy transparent areas can be selected to provide various levels of heating, as necessary or desired for a particular application. For example, when greater heating is desired, the total inactive area can be increased. By doing so, more microwave energy is transmitted to the food. Alternatively, by decreasing the total inactive area, more microwave energy is absorbed by the microwave energy-interactive areas, converted to thermal energy, and transmitted to the surface of the food to enhance browning and/or crispiness.

In a third example shown, the microwave energy interactive element comprises a plurality of substantially evenly spaced susceptor squares (shown by stippling) with a grid-like arrangement of microwave energy transparent areas therebetween. It will be understood that the dimensions of the susceptor squares and the spaces between them may vary for a particular application. Furthermore, it will be understood that the susceptor elements need not have the shape of a square. Other configurations are hereby contemplated. In this example, the gold-colored pattern on the outer surface of a food may resemble a plurality of substantially evenly spaced squares.

In a fourth example, the microwave energy interactive element comprises a plurality of concentric susceptor rings with microwave energy transparent rings or areas therebetween. In this example, the gold-colored pattern on the outer surface of a food (not shown) may resemble a plurality of substantially evenly spaced semicircles, for example, where each food covers only one platform, or a plurality of partial concentric circles , for example, where the feed covers both platforms and extends along the recess.

In a fifth example, a plurality of physical openings extend through the thickness of the tray and interrupt the microwave energy interactive element. In this example, the openings are in the form of elongated slots extending obliquely along the platforms. However, it will be understood that the openings may have any suitable configuration, for example, circular, square, triangular, oval, oblong or any other regular or irregular shape, may have any suitable configuration, for example, random, mosaic, staggered, of concentric rings, and may have any suitable placement, for example, central, peripheral or along all or part of the tray. In this example, the gold-colored pattern may include a plurality of obliquely oriented darkened areas on the outer surface of the food. These darkened areas may look like grill marks.

It will be understood that any of the various trays of the invention include a microwave energy interactive element, for example, a susceptor, which makes the tray interactive with microwave energy. In each embodiment, the microwave energy interactive element may be substantially continuous, may have one or more interruptions or discontinuities. Such interruptions or discontinuities may include non-physical openings and/or physical (vent) openings, or may have any other pattern, arrangement or configuration. It will be understood that the precise combination of characteristic features may be selected as necessary or desired to enhance the heating, browning and/or crispiness of a particular food. Although said elements can be discussed below in relation to some of the various trays of the invention, said elements are not shown in the remaining figures.

Alternatively or additionally, any of the various trays of the invention may include one or more ventilation channels that allow moisture to escape from the food, thereby enhancing the heating, browning and/or crispiness of the food.

For example, in a sixth exemplary disc or tray in accordance with various aspects of the invention, the tray includes characteristic features that are similar to the tray of the first example, except for noted variations and variations that will be understood by those skilled in the art.

In this example, a pair of substantially parallel channels (or "slits" or "notches") extend along the top face of each platform between, and optionally through one or both of, the inner face and the face. abroad. In this example, the channels are substantially parallel to and substantially equally spaced about the longitudinal centerline, and are substantially perpendicular to the transverse centerline. However, channels can have any orientation necessary or desired for a particular application. In this and other examples described herein or contemplated herein, the channels may have any suitable depth as necessary to provide the desired degree of ventilation for the particular heating application. According to the tray according to the invention of claim 1, the channels have a depth that is less than the height of the upper face, so that the bottom of at least one channel is above the plane of the edge and/or recess. from the tray.

If desired, one or both platforms can be contoured to generally conform to the shape of a food. In this example, the height of each platform is substantially uniform when viewed along the longitudinal centerline of the tray, and varies in height when viewed along the interior face of the platform. In this example, the height of the deck, and therefore the height of the top face, tapers or decreases when viewed from the longitudinal centerline toward each of the corner faces. However, other conformations and contours are contemplated.

The tray can be characterized as having various heights, lengths and radii of curvature, each of which can be varied for a particular application. The dimensions of each platform may be substantially identical or may differ, with varying degrees of symmetry being contemplated herein.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of one or both platforms, including all or a portion of each top face, inner face, outer face and/or corner face, all or a portion of the recess, and/or all or a part of one or more channels.

To use the tray, one or more foods are typically placed on each platform and placed in a microwave oven. The contoured heating surface of the platform generally conforms to the contoured surface of the food, which may vary as a result of the freezing process, and brings the susceptor closer to the surface of the food to be browned and/or crisped. .

As the microwave heating cycle continues, the susceptor converts the microwave energy into thermal energy, which is then transferred to the adjacent surface of the food. In this way, the golden color and/or crunchiness of the surface of the food can be enhanced. At least some of the steam released from the food can be directed away from the food along the channels, thereby enhancing browning and/or crispiness. Additionally, the platforms keep the food in an elevated position, which reduces the amount of sensible heat transferred from the susceptor to the ambient environment of the microwave oven, while also enhancing the browning and/or crispiness of the food. The pattern of browning and/or crustiness may include an overall darkened appearance with somewhat lighter areas corresponding to the areas lining the canals.

A seventh exemplary tray in accordance with various aspects of the invention includes characteristic features that are similar to the trays of the first and sixth examples, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the tray includes a plurality of walls that extend substantially upward from the edge or rim, which serves as the base or lower part of the tray. If desired, the walls can be finished with a ledge. A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of one or both platforms, including all or a portion of each top face, inner face, outer face and/or corner face, all or a portion of the recess, and/or all or a part of one or more channels. Such a tray may be suitable for use, for example, when the food to be heated, browned and/or crisped includes components that may otherwise fall from a tray without walls, or when it is desired that The tray serves as a container from which the food is consumed.

The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application. The specifications of each platform may be substantially identical or may differ, with varying degrees of symmetry being contemplated herein.

An exemplary eighth disc or tray in accordance with various aspects of the invention includes characteristic features that are similar to the tray of the first and sixth examples, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the tray includes four substantially parallel notches or channels extending along the top face of each platform and, optionally, across one or both of the interior face and the exterior face. Such additional channels may be desirable when additional ventilation is needed to achieve the desired degree of browning and/or crispness of a food prepared therein. The channels may be of any suitable depth as necessary to provide the desired degree of ventilation for the particular heating application.

The tray can be characterized as having various heights, lengths and radii of curvature, each of which can be varied for a particular application. The dimensions of each platform may be substantially identical or may differ, with varying degrees of symmetry being contemplated herein.

As with the various other exemplary trays of the invention, a microwave energy interactive element may be coated and attached to at least a portion of the tray. For example, a susceptor may cover all or a portion of one or both platforms, including all or a portion of each top face, inner face, outer face and/or corner face, all or a portion of the recess, and/or all or a part of one or more channels. The resulting pattern of browning and/or crispiness may include an overall darkened appearance with somewhat lighter areas corresponding to areas lining the channels, generally resembling grill marks.

A ninth exemplary tray in accordance with various aspects of the invention includes characteristic features that are similar to the tray of the first, sixth and eighth examples, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the tray includes four substantially parallel notches or channels that extend obliquely along the top face of each platform and, optionally, across one or both of the interior face and the exterior face. Such additional channels may be desirable when additional ventilation is needed to achieve the desired degree of browning and/or crispness of a food prepared therein.

The tray can be characterized as having various heights, lengths and radii of curvature, each of which can be varied for a particular application. The dimensions of each platform may be substantially identical or may differ, with varying degrees of symmetry being contemplated herein.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of one or both platforms, including all or a portion of each top face, inner face, outer face and/or corner face, all or a portion of the recess, and/or all or a part of one or more channels. The resulting pattern of browning and/or crispiness may include an overall darkened appearance with somewhat lighter obliquely oriented areas corresponding to areas overlying the channels, which generally resemble grill marks.

A nineteenth exemplary tray in accordance with various aspects of the invention includes characteristic features that are similar to the tray of the first, sixth and eighth examples, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the platforms have a substantially flat top face. Such a tray may be, in particular, well suited for use with foods having a substantially flat surface.

The tray can be characterized as having various heights, lengths and radii of curvature, each of which can be varied for a particular application.

An exemplary eleventh tray in accordance with various aspects of the invention is substantially symmetrical along a longitudinal center line and a transverse center line. However, the tray may include no symmetry lines, a single symmetry line, or multiple symmetry lines, as necessary or desired for a particular application.

In this example, the tray is substantially square in shape with somewhat rounded corners. The tray includes a somewhat flat peripheral edge or base, which serves as the base or lowest portion of the tray, and a plurality of walls extending substantially upward from the edge. If desired, the walls can be finished with a ledge. Such a tray may be suitable for use, for example, when the food to be heated, browned and/or crisped includes components that may otherwise fall from a tray without walls, or when it is desired that The tray serves as a container from which the food is consumed.

The tray includes a pair of opposing raised platforms or portions that serve as surfaces for receiving one or more foodstuffs thereon. The platforms are separated by a recess that is substantially within the same plane as the edge. In this example, the recess is along the transverse centerline.

However, the recess may have any other suitable position, as necessary or desired for a particular application. Optionally, the platforms may be further separated by a divider that extends upward along at least a portion of the length of the recess. The divider can assist the user with proper placement of food on the tray to achieve the desired level of heating, browning and/or crispness, and can assist with keeping food in the proper location on the tray during the cycle. warming up.

Still referring to the eleventh example, the platforms are somewhat elongated and rectangular in shape with rounded corners. Each platform includes a top face or surface (also called the "highest surface" and "warming surface"), a somewhat erect inner face, a somewhat erect outer face, and a pair of opposing corner faces. It will be understood that, in this and other aspects of the invention, the various faces are described as being individual surfaces or faces merely for purposes of simplicity and ease of description, and that said surfaces or faces may be substantially continuous and without having a boundary. defined between them.

The shape of the exterior surface in the top plan view generally corresponds to or "follows" the shape of the erect walls. The interior face and exterior face of each platform slope or extend obliquely, outward and downward, from the respective platform toward the recess or edge, respectively. However, in this and other aspects, it is contemplated that the various faces forming the platform according to the invention may be substantially vertical or may be tapered inward and downward from the platform, if needed or desired for a particular application. .

If desired, one or both platforms can be contoured to generally conform to the shape of a food. In this example, the thickness of each platform, and therefore the height of each top face, is substantially uniform when viewed along the longitudinal centerline of the tray, and varies in height when viewed along the inner face of the platform. In this example, the thickness of the deck, and therefore the height of the top face, decreases or tapers from the longitudinal centerline toward each of the corner faces.

The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application. The dimensions of each platform may be substantially identical, so that the tray is substantially symmetrical along each side of the longitudinal centerline and/or the transverse centerline, or they may differ, so that the tray is not symmetrical along along each side of the longitudinal center line and/or the transverse center line.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of one or both platforms, including all or a portion of each top face, interior face, exterior face and/or corner face, and/or all or a portion of the recess.

An exemplary twelfth tray according to various aspects of the invention includes some characteristic features that are similar to the tray according to the eleventh example, except for noted variations and variations that will be understood by those skilled in the art.

In this example, a pair of substantially parallel ventilation channels extend along the top face of each platform and optionally across one or both of the interior face and the exterior face. The channels may be of any suitable depth as necessary to provide the desired degree of ventilation for the particular heating application. In this example, the channels are substantially parallel to and substantially equally spaced about the longitudinal centerline, and are substantially perpendicular to the transverse centerline. However, channels can have any orientation necessary or desired for a particular application. Additionally, it should be noted that the tray does not include a transverse dividing wall.

The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application. The dimensions of each platform may be substantially identical or may differ, and varying degrees of symmetry are contemplated hereby.

If desired, a microwave-powered interactive element (not shown) may be coated and attached to at least a portion of the tray. For example, a susceptor may cover all or a portion of one or both platforms, including all or a portion of each top face, inner face, outer face and/or corner face, all or a portion of the recess, and/or all or a part of one or more channels.

A thirteenth exemplary tray in accordance with various aspects of the invention includes some characteristic features that are similar to the tray of the eleventh example, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the platforms are replaced by a plurality of substantially rectangular raised portions arranged as a pair of opposing groups separated by a transverse divider. Each group includes three raised portions arranged in a configuration substantially parallel oblique to the transverse wall. However, other numbers, conformations and arrangements of raised parts are contemplated. The raised portions within each group serve together as a platform for receiving a food thereon, the spaces between adjacent raised portions providing ventilation of the food during the heating cycle.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may coat all or a portion of one or more raised portions to enhance the heating, browning, and/or crispiness of a food heated thereon.

A fourteenth exemplary tray in accordance with various aspects of the invention is substantially triangular in shape with rounded corners and is substantially symmetrical along a longitudinal center line. However, numerous other conformations and configurations are contemplated hereby. The tray also includes a transverse center line.

The tray includes a rim or base and a plurality of walls extending upwardly from the base. The walls optionally end with a lip or boss. The tray further includes a platform or raised portion in a substantially triangular conformation that includes an upper face or surface adapted to receive a food thereon, and a plurality of somewhat erect side faces joined by somewhat arcuate corner faces. In this example, the top surface is substantially flat. However, it will be understood that contoured surfaces are contemplated herein. The side faces and corner faces extend obliquely and outward from the top surface to the base.

It will be understood that, in this and other aspects of the invention, the various faces are described as being individual surfaces or faces merely for purposes of simplicity and ease of description, and that said surfaces or faces may be substantially continuous and without having a boundary. defined between them. Furthermore, it will be understood that the platform may have any desired shape, and that numerous other regular and irregular shapes are contemplated hereby.

The various elements and aspects of the tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of the platform, including all or a portion of the top face, side faces and/or corner faces. Additionally, as with the various other examples of constructions provided herein or contemplated herein, the tray may include one or more physical openings to allow ventilation through the side walls and/or the bottom. from the tray. The tray may be used as described above in connection with the other miscellaneous exemplary trays.

A fifteenth exemplary tray in accordance with various aspects of the invention includes characteristic features that are similar to the tray of the fourteenth example, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the tray includes a plurality of channels in the platform that extend in a direction that is substantially parallel to the transverse centerline and substantially perpendicular to the longitudinal centerline. Other configurations are considered. In this example, the tray includes six channels of variable length, with shorter channels proximate a first, narrower end of the tray and longer channels proximate a second, wider end of the tray. The channels may be of any suitable depth as necessary to provide the desired degree of ventilation for the particular heating application.

The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of the platform, including all or a portion of the top face, side faces and/or corner faces and/or all or a portion of one or more channels. The tray can be used as described above.

A sixteenth exemplary tray in accordance with various aspects of the invention includes characteristic features that are similar to the tray of the fourteenth and fifteenth examples, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the tray includes a plurality of channels in the platform that extend in a transverse direction substantially parallel to the transverse centerline and substantially perpendicular to the longitudinal centerline, and a plurality of slits or channels that extend in a direction longitudinal substantially parallel to the longitudinal center line and substantially perpendicular to the transverse center line. Such additional channels may be desirable where additional ventilation is needed.

In this example, the tray includes six transverse channels of variable length, with shorter channels proximate a first, narrower end of the tray and longer channels proximate a second, wider end of the tray. The tray also includes three longitudinal channels of variable length, with the longest channel close to the longitudinal centerline and the shorter channels close to the walls. However, other configurations can be used if desired. The channels may be of any suitable depth as necessary to provide the desired degree of ventilation for the particular heating application.

The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of the platform, including all or a portion of the top face, side faces and/or corner faces and/or all or a portion of one or more channels and/or. The tray can be used substantially as described above.

A seventeenth exemplary tray in accordance with various aspects of the invention, in general, has the shape of a sector of a circle, with a pair of radial sides, an arched side and rounded corners joining the radial sides and the arched side. The tray is substantially symmetrical along a longitudinal center line. The tray also includes a transverse center line.

The tray includes a peripheral edge and a platform extending upwardly from the edge. The platform includes a substantially flat top face or surface for receiving a food item (not shown) and a plurality of abutting side faces and corner faces extending obliquely and outwardly between the top face to the edge. The platform includes a plurality of channels that extend in a generally transverse direction. In this example, the platform includes six channels of variable length, with shorter channels close to a first, narrower end of the tray, and longer channels close to a second, wider end of the tray (i.e., close to the arched side). of the tray). The channels may be of any suitable depth as necessary to provide the desired degree of ventilation for the particular heating application. Each channel may have a radius of curvature similar to that of the arched side. However, numerous other configurations are contemplated herein.

The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of the platform, including all or a portion of the top face, side faces and/or corner faces and/or all or a portion of one or more channels.

An exemplary eighteenth tray in accordance with various aspects of the invention includes characteristic features that are similar to the tray of the seventeenth example, except for noted variations and variations that will be understood by those skilled in the art.

In this example, in addition to channels extending in a generally transverse direction, the platform includes a plurality of channels extending in a generally longitudinal direction. In this example, the tray includes three generally longitudinal channels of variable length, with the longest channel close to the longitudinal centerline and the shorter channels close to the radial sides. The channels are aligned obliquely with respect to the channel and the longitudinal center line, so that each channel is substantially equidistant from the faces and the channel, which is substantially aligned with the longitudinal center line. However, the invention contemplates numerous other provisions. The various channels may have any suitable depth as necessary to provide the desired degree of ventilation for the particular heating application.

The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of the platform, including all or a portion of the top face, side faces and/or corner faces and/or all or a portion of one or more channels.

A nineteenth exemplary tray in accordance with various aspects of the invention includes characteristic features that are similar to the tray of the seventeenth example, except for noted variations and variations that will be understood by those skilled in the art.

In this example, the tray includes a plurality of side walls and adjoining corner walls extending upwardly from the edge. Such a tray might be suitable, for example, where the food heated in the tray includes components that may fall out of the food, or when it is desired that the tray be used as a container for transporting the food before or during consumption. As with the numerous other examples herein, the walls may include one or more openings extending therethrough to provide additional ventilation during the heating cycle.

A microwave-powered interactive element coats and bonds to at least a portion of the tray. For example, a susceptor may cover all or a portion of the platform, including all or a portion of the top face, side faces and/or corner faces and/or all or a portion of one or more channels. The tray can be characterized as having various heights, lengths, radii of curvature and angles, each of which can be varied for a particular application.

Numerous materials may be suitable for use in forming the various constructions of the invention, provided that the materials are resistant to softening, burning, combustion or degradation at typical microwave heating temperatures, for example, at about 121 .1°C (250°F) to approximately 218.3°C (425°F). Particular materials used may include materials interactive with microwave energy and materials transparent to or inactive with microwave energy.

Each tray is formed from a paperboard material, which can be cut into a preform before being used in the tray. For example, a tray may be formed at least partially from paperboard having a basis weight of from about 97.65 to about 537.075 g/m2 (about 60 to about 330 pounds/ream; pounds/3,000 square feet), for example. For example, from about 130.2 to about 227.85 g/m2 (about 80 to about 140 pounds/ream). The paperboard may generally have a thickness of from about 0.1524 mm to about 0.762 mm (about 6 to about 30 mils), for example, about 0.3048 mm to about 0.7112 mm (about 12 to 28 mils). In a particular example, the paperboard has a thickness of approximately 0.3048 mm (12 thousandths of an inch). Any suitable paperboard may be used, for example, a solid bleached or solid unbleached sulfate paperboard, such as SUS® paperboard, commercially available from Graphic Packaging International. Alternatively, all or a portion of the tray may be formed at least partially from a polymer or polymeric material, for example, coextruded poly(ethylene terephthalate) or polypropylene. Other materials are hereby contemplated.

The microwave energy interactive material may be an electroconductive or semiconductor material, for example, a metal or metal alloy provided as a metal foil; a metal or metal alloy deposited in a vacuum; or a metallic ink, an organic ink, an inorganic ink, a metallic paste, an organic paste, an inorganic paste or any combination thereof. Examples of metals and metal alloys that may be suitable for use with the present invention include, but are not limited to, aluminum, chromium, copper, inconel alloys (nickel-chromium-molybdenum alloy with niobium), iron, magnesium, nickel, stainless steel, tin, titanium, tungsten and any combination or alloy thereof.

Alternatively, the microwave energy interactive material may comprise a metal oxide. Examples of metal oxides that may be suitable for use with the present invention include, but are not limited to, oxides of aluminum, iron and tin, used in conjunction with an electrically conductive material where necessary. Another example of a metal oxide that may be suitable for use with the present invention is indium tin oxide (ITO). ITO can be used as an interactive material with microwave energy to provide a heating effect, a shielding effect, a browning and/or crisping effect, or a combination thereof. For example, to form a susceptor, ITO can be sprayed onto a transparent polymer film. The sputtering process typically occurs at a lower temperature than the evaporative deposition process used for metal deposition. ITO has a more uniform crystalline structure and is therefore transparent in most coating thicknesses. Additionally, ITO can be used for heating or handling purposes in the field. ITO may also have fewer defects than metals, thus making thick ITO coatings more suitable for field handling than thick metal coatings, such as aluminum.

Still, alternatively, the microwave energy interactive material may comprise a suitable electroconductive, semiconductor or non-conductive artificial dielectric or ferroelectric. Artificial dielectrics comprise conductive subdivided material in a polymeric or other suitable matrix or binder, and may include flakes of an electroconductive metal, for example, aluminum.

The substrate typically comprises an electrical insulator, for example, a polymeric film or other polymeric material. As used herein, the terms "polymer", "polymeric film" and "polymeric material" include, but are not limited to, homopolymers, copolymers, such as, for example, block, graft, random and copolymers. alternating, terpolymers, etc. and combinations and modifications thereof. Furthermore, unless specifically limited otherwise, the term "polymer" will include all possible geometric configurations of the molecule. These configurations include, but are not limited to, isotactic, syndiotactic, and random symmetries.

The thickness of the film can typically be from about 8.89 pm (35 gauge) to about 0.254 mm (10 mils). In one aspect, the thickness of the film is about 10.16 to about 20.32 pm (about 40 gauge to about 80 gauge). In another aspect, the thickness of the film is about 11.43 to about 12.7 pm (about 45 gauge to about 50 gauge). In yet another aspect, the thickness of the film is approximately 12.192 pm (48 gauge). Examples of polymeric films that may be suitable include, but are not limited to, polyolefins, polyesters, polyamides, polyimides, polysulfones, polyether ketones, cellophanes or any combination thereof.

Other non-conductive substrate materials may also be used, such as paper and paper laminates, metal oxides, silicates, cellulosics, or any combination thereof.

In one example, the polymeric film comprises poly(ethylene terephthalate) (PET). Polyethylene terephthalate films are used in commercially available susceptors, for example, the QWIKWAVE® Focus susceptor and the MICRORITE® susceptor, both available from Graphic Packaging International (Marietta, Georgia). Examples of polyethylene terephthalate films that may be suitable for use as a substrate include, but are not limited to, MELINEX®, commercially available from DuPont Teijan Films (Hopewell, Virginia), SKYROL, commercially available from SKC, Inc. (Covington, Georgia), and BARRIALOX PET, available from Toray Films (Front Royal, VA), and QU50 High Barrier Coated PET, available from Toray Films (Front Royal, VA).

The polymeric film can be selected to impart various properties to the microwave interactive structure, for example, printability, heat resistance or any other property. As a particular example, the polymer film can be selected to provide a water barrier, an oxygen barrier or a combination thereof. Such barrier film layers may be formed from a polymeric film having barrier properties or from any other barrier layer or coating, as desired. Suitable polymeric films may include, but are not limited to, ethylene-vinyl alcohol, barrier nylon, poly(vinylidene chloride), barrier fluoropolymer, nylon 6, nylon 6,6, coextruded nylon 6/EVOH/nylon 6, film coated with silicon oxide, poly(ethylene terephthalate) barrier or any combination thereof.

An example of a barrier film that may be suitable for use with the present invention is CAPRAN® EMBLEM 1200M nylon 6, commercially available from Honeywell International (Pottsville, Pennsylvania). Another example of a barrier film that may be suitable is CAPRAN® OXYSHIELD OBS monoaxially oriented coextruded nylon 6/ethylene-vinyl alcohol (EVOH)/nylon 6, also commercially available from Honeywell International. Still another example of a barrier film that may be suitable for use with the present invention is DARTEK® N-201 nylon 6,6, commercially available from Enhance Packaging Technologies (Webster, New York). Additional examples include BARRIALOX PET, available from Toray Films (Front Royal, VA) and QU50 High Barrier Coated PET, available from Toray Films (Front Royal, VA), referenced above.

Still other barrier films include silicon oxide coated films, such as those available from Sheldahl Films (Northfield, Minn.). Therefore, in one example, a susceptor may have a structure that includes a film, for example, polyethylene terephthalate, with a silicon oxide layer coated on the film, and ITO or other material deposited on the silicon oxide. silicon. If needed or desired, additional layers or coatings can be provided to protect the individual layers from damage during processing.

The barrier film may have an oxygen transmission rate (OTR) as measured using ASTM D3985 of less than about 20 cc/m2/day. In one aspect, the barrier film has an OTR of less than about 10 cc/m2/day. In another aspect, the barrier film has an OTR of less than about 1 cc/m2/day. In yet another aspect, the barrier film has an OTR of less than about 0.5 cc/m2/day. In yet another aspect, the barrier film has an OTR of less than about 0.1 cc/m2/day.

The barrier film may have a water vapor transmission rate (WVTR) of less than about 100 g/m2/day as measured using ASTM F1249. In one aspect, the barrier film has a WVTR of less than about 50 g/m2/day. In another aspect, the barrier film has a WVTR of less than about 15 g/m2/day. In yet another aspect, the barrier film has a WVTR of less than about 1 g/m2/day. In yet another aspect, the barrier film has a WVTR of less than about 0.1 g/m2/day. In yet another aspect, the barrier film has a WVTR of less than about 0.05 g/m2/day.

Other non-conductive substrate materials, such as metal oxides, silicates, cellulosics, or any combination thereof, may also be used in accordance with the present invention.

The microwave energy interactive material can be applied to the substrate in any suitable manner and, in some cases, the microwave energy interactive material is printed, extruded, sprayed, evaporated or laminated onto the substrate. The microwave energy interactive material can be applied to the substrate in any pattern and using any technique to achieve the desired food heating effect. For example, the microwave energy interactive material may be provided as a continuous or discontinuous layer or coating including circles, loops, hexagons, islands, squares, rectangles, octagons, etc. Examples of various patterns and procedures that may be suitable for use with the present invention are provided in US Patent Nos. 6,765,182; 6,717,121; 6,677,563; 6,552,315; 6,455,827; 6,433,322; 6,410,290; 6,251,451; 6,204,492; 6,150,646; 6,114,679; 5,800,724; 5,759,418; 5,672,407; 5,628,921; 5,519,195; 5,420,517; 5,410,135; 5,354,973; 5,340,436; 5,266,386; 5,260,537; 5221.419; 5,213,902; 5,117,078; 5,039,364; 4,963,420; 4,936,935; 4,890,439; 4,775,771; 4,865,921; and Re. 34,683.

It will be understood that although susceptor elements are discussed in detail herein, numerous other microwave energy interactive elements and combinations thereof are contemplated herein. For example, the microwave interactive element may comprise a sheet having a thickness sufficient to protect one or more selected parts of the food from microwave energy (sometimes referred to as a "protection element"). Such protective elements can be used when the food is prone to burning or drying out during heating.

The protective element can be formed from various materials and can have various configurations, depending on the particular application for which the protective element is used. Typically, the shielding element is formed from a conductive reflective metal or metal alloy, for example, aluminum, copper or stainless steel. The shielding element, in general, may have a thickness of from about 0.0007239 cm (0.000285 inches) to about 0.127 cm (0.05 inches). In one aspect, the protection element has a thickness of from about 0.000762 cm (0.0003 inch) to about 0.0762 cm (0.03 inch). In another aspect, the protection element has a thickness of from about 0.000889 cm (0.00035 inch) to about 0.0508 cm (0.020 inch), for example, 0.04064 cm (0.016 inch). As yet another example, the microwave interactive element may comprise a segmented sheet, such as, but not limited to, those described in US Patent Nos. 6,204,492, 6,433,322, 6,552,315 and 6,677. .563. Although the segmented leaves are not continuous, appropriately spaced groupings of such segments often act as a transmission element to direct microwave energy to specific areas of the food. Such sheets can also be used in combination with other elements, for example, susceptors.

It will be understood that, with some combinations of elements and materials, the microwave interactive material or element may have a gray or silver color that is visually distinguishable from the substrate or other components in the structure. However, in some cases, it may be desirable to provide a structure that has a uniform color and/or appearance. Such a structure may be more aesthetically pleasing to a consumer, in particular, when the consumer is accustomed to containers, containers, trays or other constructions that have certain visual attributes, for example, a solid color, a particular pattern, etc. Therefore, for example, the present invention contemplates using an adhesive in silver or gray tones to attach the microwave interactive elements to the substrate, using a substrate in silver or gray tones to mask the presence of the microwave interactive element in silver or gray tones , use a substrate in dark tones, for example, a substrate in black tones, to hide the presence of the microwave interactive element in silver or gray tones, overprint the metallic side of the band with an ink in silver or gray tones to hide the color variation, printing the non-metallic side of the structure with a silver or gray ink or other concealing color in a suitable pattern or as a solid color overlay to mask or hide the presence of the microwave interactive element, or any other technique suitable or combination thereof.

EXAMPLES 20-31

Commercially available frozen Lean Cuisine and Corner Bistro sandwiches were evaluated using various trays and microwave ovens. Each sandwich was heated on full power for approximately 3 minutes and 20 seconds unless otherwise noted. The results of the evaluations are presented in table 1, where:

control disk = a corrugated cardboard with a susceptor covering one surface and six elongated openings with enlarged, rounded ends extending through the thickness of the disk (provided with food);

LC = Lean Cuisine;

CB = Corner Bistro;

A = Amana 1000 W, 0.0255 m3 (0.9 cu ft), 31.75 cm (12.5 in) swivel diameter;

B = Panasonic 1100 W, 0.0283 m3 (1.0 cu ft), 34.29 cm (13.5 in) swivel diameter;

C = Panasonic 1200 W, 0.0255 m3 (0.9 cu ft), 34.29 cm (13.5 in) swivel diameter;

D = Amana Radarange 1000 W, 0.0311 m3 (1.1 cu ft), without turntable;

E = Panasonic 800 W, 0.0198 m3 (0.7 cu ft), 24.13 cm (9.5 in) swivel diameter;

F = Samsung 700 W, 0.0198 m3 (0.7 cu ft), 27.94 cm (11 in) turntable diameter; and G = Panasonic 1100 W, 0.0311 m3 (1.1 cu ft), 35.56 cm (14 in) turntable diameter (cooking time increased to 4 min);

and where:

0 = no browning and/or crunchiness;

7 = optimal golden color and/or crispness; and

1, 2, 3, 4, 5 and 6 = various intermediate degrees of golden color and/or crispness between 0 and 7.

EXAMPLE 32

Commercially available frozen Stouffer's Corner Bistro Italian grilled chicken panini sandwiches were heated using various trays to compare the level of browning achieved on the surface of the food.

A first sandwich was placed in an open-face configuration on the susceptor disk provided with the sandwich (referred to as "control disk" in examples 20-31). The sandwich was heated according to package instructions for 3 minutes in a 1100 W Panasonic microwave oven.

A second sandwich was heated for 3 minutes in the same 1100 W Panasonic microwave oven using a tray according to the eighth example according to the invention.

A Konica Minolta BC-10 baking meter with an opening size of approximately 1.111 cm (7/16 inches (0.4375 inches)) was used to measure the level of browning on the surface of the bread piece at designated locations. . Measurements taken in each position were averaged for the two pieces of bread in each sandwich. Results are presented in Baking Contrast Units ("BCU"), where the lower the BCU, the darker the color (i.e., the greater the degree of browning). The results of the evaluation are presented in table 2.

Table 2.

Although certain embodiments of the present invention have been described with a certain degree of particularity, those skilled in the art could make numerous modifications to the disclosed embodiments without departing from the spirit or scope of the present invention. All directional references (for example, top, bottom, up, down, left, right, left, right, above, below, vertical, horizontal, clockwise, and counterclockwise) are only They are used for identification purposes to assist the reader's understanding of the various embodiments of the present invention, and do not create limitations, in particular, as to the position, orientation or use of the invention, unless specifically set forth in The claims. Joining references (e.g., joined, fixed, coupled, connected, and the like) should be interpreted broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, join references do not necessarily imply that two elements are directly connected and in a fixed relationship with each other.

Those skilled in the art will recognize that various elements discussed with reference to the various embodiments can be interchanged to create entirely new embodiments that fall within the scope of the present invention as defined in the claims. All material contained in the foregoing description is intended to be construed only as illustrative and not limiting. Changes may be made in detail or structure without departing from the invention as defined in the appended claims.

Accordingly, it will be readily understood by those skilled in the art, in view of the above detailed description of the invention, that the present invention is susceptible of wide utility and application. Many adaptations of the present invention other than those described herein, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention as defined by the appended claims.

Claims (15)

1. A microwave heating tray, comprising: a cardboard material, wherein the cardboard material is configured to define a substantially flat base; a platform extending upwardly from the base, the platform including a heating surface that is elevated with respect to the base, a face extending outwardly and downwardly from the heating surface toward the base, at least one upwardly open channel extending at least partially along the platform; and interactive material with microwave energy attached to at least the heating surface, characterized in that The at least one upwardly open channel includes a lower part located between the base and the heating surface, so that the bottom part of the channel is elevated with respect to the plane of the base. 2. The tray of claim 1, wherein the platform has a substantially domed conformation. 3. The tray of claim 1, wherein the platform has a contoured shape. 4. The tray of any of claims 1 to 3, wherein the platform is a first platform of a pair of platforms. 5. The tray of claim 4, wherein each of the platforms are substantially semicircular in conformation. 6. The tray of claim 4 or 5, wherein the platforms are separated by a recess. 7. The tray of claim 6, wherein a lower portion of the recess is substantially coplanar with the base. 8. The tray of any of claims 1 to 7, wherein the channel comprises a notch in the platform. 9. The tray of any of claims 1 to 8, wherein the channel extends linearly at least partially along the platform. 10. The tray of any of claims 1 to 9, wherein the channel extends in a curved manner at least partially along the platform. 11. The tray of any of claims 1 to 10, wherein the channel is a first of a plurality of channels extending at least partially along the platform. 12. The tray of claim 11, wherein at least some of the plurality of channels are parallel to each other. 13. The tray of claim 11 or 12, wherein at least some of the plurality of channels are perpendicular to each other. 14. The tray of any of claims 1 to 13, wherein the base includes a periphery, and a wall extends substantially upward along at least a portion of the periphery of the base. 15. The tray of any of claims 1 to 14, wherein the microwave energy interactive material is functional for heating in response to microwave energy.