Background A digital versatile or video disc (hereinafter DVD) is a plastic circular disc that has recorded digital information stored thereon, for example, video recordings and data, films, computer games and computer data. DVDs are typically said and stored in trays that are made of a plastic material. One of the more significant problems associated with the manufacture of DVD trays is that the trays warp when they are removed from the molds used to form them. This warping of the tray bends and twists the tray out of shape. It is difficult, if not impossible, to position a disc in such a wrapped tray. In an attempt to counter such problematic warping, standard DVD tray designs require the tray to be thick and heavy. This increases the amount of plastic required per tray, which increases production and1 shipping costs. Another significant problem associated with these trays is that they are incapable of being stacked into stable piles. This causes problems during the manufacture of the trays, for example, when the DVD trays have to be stacked and transported. Thus, there is a need for a better DVD tray. Summary In one of the preferred embodiments, the tray- is a thin digital versatile/video disc (hereinafter DVD) tray. The tray comprises a body of polystyrene that has a planar tray portion having a first tray surface and a stacking surface. An integrally formed rib extends from the planar tray portion between the first tray surface and the stacking surface. The stacking surface extends to a first edge, second edge, third edge, and fourth edge of the tray. The rib is. continuous and has straight portions along the edges of the tray, and it has curved portions at the corners of the tray. In one preferred embodiments the rib has a rectangular shaped cross ■ section, and in another preferred embodiment the rib has a curved or semicircular cross section. The rib advantageously prevents the tray from warping and strengthens the tray with a minimal amount of material ' and weight. Thus, the rib advantageously decreases the amount of polystyrene used to form the tray, which advantageously decreases production- costs. The rib also advantageously allows for a number of trays to be stacked, with the rib of one tray providing for the alignment of a tray that is stacked on top of it. The tray further comprises a surrounding circular wall that is joined to the planar tray portion and a base wall. The surrounding circular wall and base wall define a DVD recess. The base wall has a centrally located step or raised portion, and an annular array of five fingers extends from the step portion in the central region of the base wall. A DVD having an opening can be releaseably attached to the fingers. A plurality of radially outwardly extending support arms are located between adjacent fingers, and they connect with the step portion. During impact, for example during installation of the disc on the tray, the support arms and step radiate the energy of impact directly outwardly to the base wall and advantageously act as a buffer for the fingers. The tray further comprises a first side wall, a second side wall, a third side wall, and a fourth side wall. These side walls extend from the planar tray portion, and each side wall has an end surface. The trays can be stacked one on top of another, such that the end surfaces of the first, second, third, and fourth side walls of one tray contact and are supported on the stacking surface of the tray it is positioned on. In this arrangement, the first, second, third, and fourth side walls of the tray straddle the rib of the tray that supports it. In addition, the first, second, third, and fourth side walls flare outwardly in one of the preferred embodiments to facilitate such stacking. There is also provided a method of making a tray comprising providing a mold, providing polystyrene, forming a tray with a planar tray portion having a first planar surface, forming a surrounding circular wa?ll and a base wall, and forming the tray with first, second, third, and fourth side walls having end surfaces, forming a rib in the tray that extends from the planar tray portion and extends along first, second, third, and fourth edges of the tray, providing the rib with curved portions or sections at the corners of the tray, providing a stacking surface on the tray extending between the rib and first, second, third, and fourth edges, forming a step in the tray and forming fingers around the step, and forming a hub in the tray at a central location between the fingers.

Brief Description o-f Drawings This invention is illustrated in the drawings in which like reference numbers designate the same or similar parts. FIG. 1 is a top plan view of the tray. FIG. 2 is a bottom perspective view of the tray. FIG. 3- is a sectional view of the tray taken along cut line A-A of FIG. 1. FIG. 3A is a sectional view of the tray taken along cut line A-A of FIG. 1 in which the tray supports a disc. FIG. 4 is a sectional view of the tray taken along cut line B-B of FIG. 1. FIG. 4A is a sectional view of the tray taken along cut line B-B of FIG. 1 in which the tray supports a • disc. FIG. 5 is a sectional view of the tray taken along cut line C-C of FIG. 1. . FIG. 5A is an enlarged view, partly in section, of FIG. 5. FIG. 6 is a sectional view of the tray taken along cut line D-D of FIG. 1. FIG. 6A is an enlarged view, partly in section, of FIG. 6. FIG. 7 is a sectional view of a stack of the trays orientated as shown in FIG. 3. FIG. 8 is a sectional view of a stack of the trays orientated as shown in FIG. 4. FIG. 9 is an enlarged view, partly in section, of a stack of trays, similar to that of FIG. 8, wherein the rib is embodied with a curved or semicircular shaped cross section. FIG. 10 is an enlarged view, partly in section, of the base wall of the tray and the fingers.

Detailed Description FIGS. 1 and 2 generally show one of the preferred embodiments of the digital versatile disc (hereinafter DVD) tray 20. The tray 20 is used for holding a DVD 18, as shown in FIGS. 3A and 4A. In one of the preferred embodiments, the tray 20 is integrally formed and comprises a molded thermoplastic material, such as clear polystyrene. The tray 20 has a length, designated L in FIG. 1, that can be about eighteen (18) ■ centimeters, and a width, designated W in FIG. 1, that can be about fourteen (14} centimeters. In other embodiments, the dimensions of the tray 20 can be more σr less. FIG. 1 shows the first side 25 of the tray 20-, and FIG. 2 shows the second side 27 of the tray 20. The disc 18, shown in FIGS. 3A and 4A, is releasable joined to the first side 25 in a manner to be described presently. As shown in FIG. 1, the tray 20 comprises body 22 and has a planar tray portion 24 having a first tray surface 26. In one of the preferred embodiments, the first tray surface 26 is planar. Formed in the tray 20 and joined to the planar tray portion 24 is a surrounding circular shaped wall 30 having a surrounding wall surface 31. The surrounding circular wall 30 is joined to a base wall 34 having a base wall surface 36, such that the base wall surface 36 is recessed relative to the first tray surface 26, as shown in FIGS. 3 and 4. The surrounding circular wall 30 and base wall 34 define a generally circular shaped DVD recess 32 that is sized to receive a DVD 18. As shown in FIG. 1, curved finger contacting walls 38 having finger contact surfaces 40 extend from the planar tray portion 24 to the base wall 34. FIG. 1 shows four such finger contacting walls 38. The finger contacting walls 38 form finger recesses 42 in the tray 20 that extend to the disc recess 32. The finger recesses 42 are used for providing clearance for a finger (not shown) when a disc 18 is being manually installed or removed from the tray 2-Q. As shown in FIGS. 2-4, the tray 20 has spaced apart first and second side walls 50, 52, respectively, that are joined to the planar tray portion 24. The first and second side walls 50, 52, respectively, extend along- the length, designated L in FIG. 1, of the tray 20. As shown in FIG. 2, the tray 20 has spaced apart third and fourth side walls 54, 56, respectively, that are joined to the planar tray portion 24. The third and fourth walls 54, 56, respectively, extend along the width, designated W in FIG. 1, of the tray 20. Each of the first and second side walls 50, 52, respectively, meets with and is joined with each of the third and fourth side wallsr 54, 56, respectively, as shown in FIG. 2 at corners 68. As best shown in FIG. 2, the first, second, third, and fourth side walls 50, 52, 54, 56, respectively, collectively surround the base wall 34. In addition, each of the first, second, third, and fourth side walls 50, 52, 54, 56, respectively, terminates at a substantially planar end surface, commonly designated 57 throughout the figures. FIG. 5 shows a sectional view of the tray taken along cut line C-C of FIG. 1, and FIG. 5A is an enlarged view of a portion of FIG. 5. As shown, the first and second side walls 50, 52, respectively, meet with the planar portion 24 of the tray 20 at first and second edges 58, 60, respectively. FIG 6 shows a section view of the tray 20 taken along cut line D-D- shown in FIG. 1, and FIG. 6A is an enlarged view of a portion of FIG.. 6. The third and fourth side walls, 54, 56, respectively, meet with the planar tray portion 24 at third and fourth edges 62, 64, respectively. As shown in FIGS. 1 and 3-8, a rib 70 extends from the first side 2S of the tray 20, and more particularly, from the first tray surface 26 of the planar tray portion 24. In one of the preferred embodiments the rib 70 is integrally formed with the tray 20 and- extends continuously along the first, second, third, and fourth edges 58, 60, 62, 64, respectively, as shown in FIGS. 1, 5-6. As shown in FIGS. 5A and 6A, the rib 70 has a generally rectangular shaped cross section. The rib 70 has a first rib surface 73, a second rib surface 75, and a third rib surface 77 that extends between the first and second rib surfaces 73, 75, respectively. Another preferred embodiment of a rib 70a is shown in FIG. 9, wherein the rib 70a has a curved surface 71. The rib 70 can be embodied with other cross sections in other preferred embodiments. The first tray surface 26 extends along the planar tray portion 24 from the surrounding circular wall 30 to the rib 70, as shown in FIG. 1. As shown in FIGS. 1 and 5-6, the planar tray portion 24 also has a stacking surface 74 that extends from the first, second, third, and fourth edges 58, 60, 62, 64, respectively, to the rib 70. As shown in FIGS. 5A and 6A, the stacking surface 74 is substantially planar and is substantially coplanar with a plane that passes through the first tray surface 26. FIGS. 5A and 6A also show the rib 70 is positioned between the first tray surface 26 and stacking surface 74, and that the rib 70 extends a distance, designated D in FIG. 5A, from the first tray surface 26 and stacking surface 74. As shown in FIG. 1, the rib 70 has a first rib portion 76 that extends along the first edge 58, a second rib portion 78 that extends along the third edge 62, a third rib portion 80 that extends along, the second edge 60, and a fourth rib portion 82 that extends along the fourth edge 64. The rib 70 also has curved rib portions, commonly designated 84, that extend continuously between the first and second rib portions 76, 78, respectively, the second and third rib portions 78, 80, respectively, the third and fourth rib portions 80, 82, respectively, and the fourth and first rib portions 82, 76, respectively to form the rib 70. The first, second, third, and fourth rib portions 76, 78, 80, 82, respectively, are substantially straight where they extend along the first, second, third, and fourth edges . 58, 60, 62, 64, respectively. Also, as shown in FIG. 5A, where the first, second, third, and fourth rib portions 76, 78, 80, 82, respectively, are substantially straight, they are spaced a distance, designated G in FIG. 5A, away from the nearest edge. In one of the preferred embodiments, the rib 70 extends continuously around the tray 20, as shown in FIG. 1. The curved rib portions 84 allow the rib 70 to curve around the corners 68 of the tray 20. As shown in FIG. 5 1, where there are curved rib portions 84, the stacking surface 74 extends from the curved portion 84 to the first edge 58 and the third edge 62, the third- edge 62 and the second edge 60, the second edge 60 and the fourth edge 64, and the fourth edge 64 and the first edge 58. In another embodiment, the rib can be formed such that it is not continuous. As previously mentioned, the rib 70 advantageously prevents the tray 20 from warping when the tray 20 is removed from the mold (not shown)- used to form it. Some of the additional advantages of the rib 70 are that it advantageously provides the tray 20 with added strength yet adds only a minimal amount of weight. This : advantageously reduces the amount of material used to manufacture the trays 20 and advantageously decreases production costs associated with the manufacture of the trays 20. The stacking surface 74 is advantageously used for supporting the end surfaces 57 of the sidewalls of an adjacent tray 20 that is placed thereon, to thus form a stack 21 of trays 20 as will be more fully described presently. FIG. 3 shows a sectional view of the tray 20 taken along cut line A-A of FIG. 1. FIG. 3A is a similar view with a disc 18 positioned in the tray 20. FIG. 4 shows a sectional view of the tray 20 taken along cut line B-B of FIG. 1. FIG. 4A is a similkr view with a disc 18 positioned in the tray 20. FIG. 8 shows a sectional view the same as the sectional view of FIG. 4, except FIG. 8 shows a stack of trays 21 comprising two trays 20, wherein adjacent trays 20 contact one another. As shown in FIG. 2 and described 5 above, each of the first, second, third, and fourth side walls 50, 52, 54, and 56, respectively, of the tray 20 has the end wall surface 57. When the trays 20 are stacked, as shown in FIGS. 7-8, the end walls 57 of the first, second, third, and fourth side walls 50-, 52, 54, 1.0 56, respectively, contact the stacking surface 74 of the adjacent tray 20. Thus, in a stack 21 of trays 20, the end walls 57 of one tray 20 are advantageously supported ■ on the stacking surface 74 of an adjacent tray 20. In addition to the above described advantages 15 of the rib, the rib 70 shown in FIGS. 7 and 8 advantageously allow trays to be stacked into a stack 21 ■. . of trays 20. When the trays 20 are stacked, the rib 70 of one tray 20 is advantageously surrounded or straddled :• by the first, second, third, and fourth side walls 50, 20 52, 54, and 56, respectively, .of the tray 20 stacked on top of it. Therefore, once stacked, the trays 20 remain aligned because the first, second, third, and fourth side walls, 50, 52, 54, 56, respectively, cannot slide over or move past the rib 70 of the tray 20 it is positioned on. 2.5 In such a stack 21, the end surfaces 57 of one tray 20 maintain contact with the stacking surface 74 of the tray it is positioned on. This advantageously allows the trays 20 to be piled into extremely stable stacks 21 that do not tip over. The rib 70a shown in FIG. 9 allows 30 trays 20 to be stacked into stable stacks in a similar manner. 21

As shown in FIGS-. 5A, 6A, and 9, each of the first, second, third, and fourth side walls 50, 52, 54, 56, respectively, advantageously flares outwardly a distance designated F, from the planar tray portion 24. This is to allow contact between the end surfaces 57 of one tray 20 and the stacking surface 74 of the tray it is positioned on. Enlarged views 5A, 6A, and 9 are representative of how the trays 20 contact one another when stacked. Thus, as shown in FIGS. 7 and 8, the first, second, third, fourth side walls 50, 52, 54, 56, respectively, flare outwardly such that they can straddle the rib 70 of the tray 20 that they contact and are supported on. The amount the first, second, third, and fourth side walls 50, 52, 54, 56, respectively, flare outwardly is between about one (1) and about five (5) degrees. This amount could be more or less in other preferred embodiments. In another preferred embodiment, there is no outward flaring of the first, second, third, and fourth side walls 50, 52,, 54, and 56, respectively, from the planar tray portion 24. In such an embodiment, stacking of the trays 20 is still possible.because of the rib 70. In addition to advantageously providing for tray 20 alignment and stackability, the rib 70 has other advantages. As previously described, trays currently in use are thick and heavy in order to withstand warping forces. Such warping of trays is well known to those having ordinary skill in the art. The tray 20 with integral rib 70 provided for herein advantageously eliminates* warping problems. This is because the rib 70 resists the warping forces that would otherwise cause the tray 20 to bend and/or warp. The strength provided by the rib 70 also advantageously allows the tray 20 to be made thinner, so that less plastic/polystyrene is required to make each tray 20. In particular, the use of the rib 70 allows the tray 20 to be about twenty-five percent (25%) lighter than trays currently on the market of similar length and width. Thus, the rib 70 advantageously provides for superior strength and durability, eliminates problematic DVD tray 20 warping, and decreases production costs because less polystyrene or plastic is required for each tray,20. As shown in FIGS. 1, 3, 4 and 10, the base wall 34 extends to and surrounds a circular step 91 which is used for supporting the DVD 18. Formed integral with the step 91 is an arrangement of fingers 94, as shown in FIGS. 1 and 10. In particular, -there are five (5) fingers 94a, 94b, 94c, 94d-, and 94e, respectively, separated by openings 97. The fingers 94a-94e are spaced at substantially equal distances from one another, as shown. The fingers 94a-94e are annularIy spaced relative to the center of the circle defined by step 91, which serves as a reference point. The fingers 94a-94e are resilient and are used for receiving the central opening of a DVD 18, as shown in FIGS. 3A and 4A. DVDs having central openings are well known to those having ordinary skill in the art. The fingers 94a-94e are for releasably holding the DVD 18 on the tray 20. The fingers 94a-94e are substantially identical in structure, shape and size, and for convenience only, one will be described, it being understood that the description of any finger applies equally to each of the fingers 94a-94e. FIG. 10 shows an enlarged view, partly in section, of the fingers 94a-94c. A pair of radially inwardly extending slots 96 and 98 are provided between each of the fingers 94a-94e. Finger 94a has a first portion 100 extending upwardly from the step 91 of the tray 20, in a direction generally perpendicular to the plane that passes through the step 91. The first portion 100 is generally rectangular shaped, and it is formed integral with the step 91. The first portion 100 has i extending therefrom a second portion 102. The second portion 102 has a truncated triangular shape and extends radially inward, and the second portion 102 is disposed in a plane substantially parallel to the plane of the step 91. The first portion 100 also has an integral outwardly extending protrusion 103 that is for engaging the disc 18. The truncated triangular portions 102 of the fingers 94a-94e are arranged in an annular array about the center of the circle defined by the annular step 91. When a DVD 18 is fitted on tray 20, the resilient fingers 94a-94e bend inwardly, such that the DVD 18 moves past them and the protrusions 103 that extend from them. The fingers 94a-94e thereafter hold the DVD to the tray 20. The DVD 18 can be readily installed or removed by pushing on the fingers 94a-94e, because pushing on the fingers 94a-94e provides clearance for the opening in the DVD 18. In addition, molded thermoplastic material, such as general purpose polystyrene, is relatively brittle. Thus, the fingers 94a-94e are subject to breakage when encountering impact forces which can occur during automated installation of a DVD 18 on a tray 20, placement of the tray 20 in packaging, or when heavy loads are stacked on the DVD 18 package during, mail handling of the tray 20. As shown in FIGS. 1 and 10, to prevent such breakage, the tray 20 has an integrally formed impact resistant shield 110 in the central region of the tray 20 within step 91. The shield 110 is advantageously positioned in the region of the annular array of fingers 94a-94e, and the shield 110 advantageously receives incoming impact forces that are directed toward the fingers 94a-9"4e, and redistributes these forces to the remainder of the tray 20, such that the fingers 94a-94e do not break upon an impact. As shown in FIG. 10, the shield 110 has a central body portion or hub 112, and five radially outward extending portions in the form of support arms 114a, 114b, 114c, 114d, and 114e, respectively, support the hub 112. As shown in FIG. 10, the central hub 112 is positioned radially inwardly of the fingers 94a-94e. The central body portion or hub 112 has a concave surface 116 that allows room for the second portions 102 of the fingers 94a-94e to be pressed downwardly, without hindrance and for easy release of a DVD 18. There is also a method of making a tray 20 comprising providing a mold, providing polystyrene, forming a tray 20, forming a planar tray portion 24 having a first planar surface 26, forming a surrounding circular wall SO- and a base wall 34, forming the tray with first, second, third, and fourth side walls 50, 52, 54, and 56, having end surfaces 57, forming a rib 70 in the tray 20 that extends from the planar tray portion 24 and extends along first, second, third, and fourth edges 58, 60, 62, 64, respectively, of the tray 20, providing the rib 70 with curved portion 84 at the corners 68 of the tray 20, providing a stacking surface 74 on the tray extending between the rib and first, second, third, and fourth edges 58, 60, 62, 64, respectively, forming a step in the tray 20 and forming fingers 94a-94e around the step 91, and forming a hub 112 in the tray 20 at a central location between the fingers 94a-94e. It is to be understood that various changes in the materials, steps, and arrangements which have been described herein in detail and set forth and describe the nature of the tray 20 may be made by those skilled in the art within the principles and scope of the tray 20.