FOR PACKING OPTICAL ELEMENTS

The invention relates to a packaging for optical elements and a method for packing optical elements into a packaging. The optical elements may, in particular, be spectacle lenses.

Semifinished or finished spectacle lenses are currently packed into individual packagings for transport to the optician or another destination where the lenses are further finished and/or fitted into frames. Packing and unpacking spectacle lenses into such individual packagings is laborious and time- consuming and requires a substantial amount of packaging mate rial. In many cases such packagings require additional inlays made of foam or other soft materials for adequate protection of the individual lens and in particular the optical surfaces of the lens.

It is the object of the present invention to provide a packag ing for optical elements, in particular, spectacle lenses, and methods for packing optical elements, in particular spectacle lenses, into such a packaging which are more efficient and re quire less packaging material.

A first aspect of the invention is the use of a flexible paper sheet material for forming a packaging for a plurality of op tical elements, characterized in that the flexible paper sheet material is configured to radially hold a circumference of the optical element, the flexible paper sheet material further comprising radially inward protruding paper sheet material portions for axial support of a rim of the optical element.

First, some terms used in the context of the invention are de fined.

The packaging for optical elements of the invention provides sufficient protection for optical elements during transport and storage.

Typically, such optical elements comprise at least one fin ished surface (either the front or rear surface) and may com prise two finished surfaces. An optical element may be sub stantially translucent, transparent, or reflective. More in particular, an optical element may be a lens or a mirror. In particular, the optical element may be a spectacle lens. The term spectacle lens, as used herein, includes spectacle lens blanks and spectacle lens semi-finished products. A spectacle lens blank is understood to mean a usually pre-shaped piece of material for producing a lens, in any state before the surface treatment has been completed. Spectacle lens semi-finished products are lens blanks where the optical processing has only been finished on one surface. In most cases, such spectacle lenses are essentially cylindrical and do not comprise the fi nal circumferential shape for fitting into a frame. The pack aging is typically used for transport and storage prior to this final fitting. The circumference of the optical element is defined by the radially most outward protruding part of the optical element.

The weight of an optical element may be between 5 g and 250 g, preferably between 35 g and 120 g, more preferably between 75 g and 85 g. A diameter of an optical element may be between 20 mm and 150 mm, preferably between 40 mm and 100 mm, more pref erably between 60 mm and 80 mm.

The packaging is designed for a plurality of optical elements. A plurality is two or more. Often, packaging is designed for 5 to 20 optical elements, preferably 10 optical elements. The packaging may carry as many optical elements as possible as long as it can securely hold the optical elements.

The packaging comprises a flexible paper sheet material. The flexibility of the material is sufficient to fit the paper sheet material around the circumference of the optical element so that it can radially hold this circumference. This provides radial support to each optical element in the packaging.

The flexible paper sheet material further comprises radially inward protruding paper sheet material portions for axial sup port of the rim of the optical element. In this context, the terms "radial" and "axial" refer to the plane of the optical elements packed into the packaging. The plurality of optical elements is stacked into the packaging on top of each other in axial direction. Axial support therefore means that optical elements stacked on top of or above each other are secured against axial dislocation. While the packaging often will have an essentially cylindrical shape with the circumference of each optical element forming essentially a circle, the inven tion is not limited thereto. The circumference of the optical element and the corresponding shape of the packaging might have a different shape, e.g. oval. The term "radial", as used herein, is not intended to limit the invention to a cylindri cal shape. This axial support is provided for the rim of the optical ele ment, i.e. an area of the optical element close to its outer circumference. It is provided by radially inward protruding paper sheet material portions. This means that the axial sup port is provided by the paper sheet material itself, not by separate mounts affixed to the paper sheet material. Parts of the paper sheet material are protruding radially inward thereby providing axial support for the respective parts of the rim of the optical element.

The invention provides a simple, cost efficient and easy-to- use packaging for the plurality of optical elements. The opti cal elements are stacked in the packaging so that the packag ing filled with the plurality of optical elements typically has an essentially cylindrical shape, the diameter correspond ing to the diameter of the optical elements plus the compara tively small thickness of the paper sheet material, and the height approximately corresponding to the sum of the axial space requirement of the optical elements plus the sum of the axial distances between the optical elements within the pack aging.

Axial support of the rim of the optical element preferably is provided on both sides, front and back surface of the optical element. Preferably, the rim of the optical element fits be tween two axial supports so that the optical element is se cured against axial dislocation, i.e. the axial distance be tween these axial supports essentially corresponds to the ax ial thickness of the rim of the optical element.

The paper sheet material is a sheet material which comprises paper or which consists essentially or entirely of paper. The paper may be produced, for instance, by mechanically or chemi cally processing cellulose fibers obtained from wood, rags, grasses, or other plant sources in water, draining the water through a fine mesh so that the fibers remain evenly distrib uted on the surface, followed by pressing and drying. A spe cific weight of the paper may be between 20 g/m ² and 225 g/m ² , preferably between 60 g/m ² and 180 g/m ² , more preferably be tween 80 g/m ² and 140 g/m ² . Such a paper is readily available, easy to handle and recyclable. Types of paper suitable for be ing used within the invention are disclosed in DIN 6730:2017- 09. The paper sheet material may comprise paper which is coated with a coating material such as a polymeric material.

In an embodiment of the present invention, instead of using a paper sheet material, a sheet material may be used which com prises or consists of cardboard and/or a polymeric material. Preferred values for the specific weight of paper or cardboard are 80 to 500 g/m ² , preferably 120 to 250 g/m ² . Cardboard has a higher specific weight than paper.

In a particularly preferred embodiment, the packaging formed using the flexible paper sheet material comprises an essen tially rectangular paper sheet with two opposing edges (sides) joined together so as to form an essentially cylindrical pack aging. For joining the edges together, the rectangular paper sheet may comprise appropriate adhesive stripes or other ap propriate affixing means. The rectangular paper sheets may be stored as flat paper sheets prior to use and assembled to form an essentially cylindrical packaging during the packing pro cess. The assembly process is very simple compared to prior art folded boxes. An essentially rectangular paper sheet is rectangular within the limits and tolerances of manufacture and measurement of such a paper sheet. An essentially cylin drical packaging is adapted to the shape of the circumference of the optical element and therefore may deviate from a cylin drical shape to the extent this circumference deviates from a cylindrical shape. In one embodiment, an essentially rectan gular paper sheet can be an isosceles trapezoid and an essen tially cylindrical packaging can be in a form of oval.

In one embodiment of the invention, the axial distance between two axial supports for two neighboring optical elements is adapted to the maximum axial space requirement of an optical element. The maximum axial space requirement is measured from the respective parts of the front face and rear face of the optical element which are the most outward protruding parts in front and rear axial direction. For a typical optical element with a front face curvature, this axial space requirement is the axial distance from the rearward facing edge of the rim of the optical element to the center of the front face of the op tical element. The maximum axial space requirement typically is larger than the maximum thickness (or maximum axial thick ness) of the optical element which may be the thickness at the rim of the optical element or the thickness in the center of the optical element. Adaptation to the maximum axial space re quirement allows prefabrication of the packaging according to previously provided optical element specifications including this maximum axial space requirement. Alternatively, it is possible to provide the inward protruding paper sheet material portions on site immediately prior to packing the optical ele ments (details see below) so that the axial distance can be adapted to the axial space requirement of the actually packed optical elements.

In a preferred embodiment, the packaging comprises axial and/or radial perforations for opening the packaging. Axial perforations run along the axial length of the packaging cyl inder and allow an easy opening of the packaging to remove all optical elements. A radial perforation preferably runs along the complete circumference of the packaging between two neigh boring optical elements and allows easy removal of a single optical element or some optical elements through circumferen tial opening of the packaging. The packaging may comprise more than one such radial perforation, and may comprise a radial perforation between each of the adjacent neighboring optical elements. The term perforation as used herein includes tear strips.

In a particularly preferred embodiment, the paper sheet com prises pairs of parallel circumferential cuts, each pair en closing a sheet portion radially protruding inward (cutout portion) for providing axial support of the rim of the optical element.

This embodiment enables to provide the radially inward pro truding paper sheet material portions from the simple flat pa per sheet material. A pair of parallel circumferential cuts encloses a circumferential, essentially rectangular paper sheet material portion separated from the remaining paper sheet material through the circumferential cuts (in axial di rection) and being connected to the remaining paper sheet ma terial at its circumferential end portions. When the complete paper sheet material forms an essentially cylindrical packag ing, this paper sheet material portion can be pushed radially inwards and remains in this position due to the tension of the paper sheet material. The cutout paper sheet material portions flexed radially inwards therefore provides axial support for the rims of the optical element in a simple and efficient man ner. The circumferential cuts and the corresponding paper sheet portions can easily be adapted to provide axial support for optical elements of varying thickness.

Preferably, the packaging comprises at least two, preferably at least three, further preferred four pairs of parallel cir cumferential cuts around the circumference of the packaging. This provides axial support of the rim of the optical elements in at least two, preferably three, further preferred four ar eas around the circumference of the optical element. Prefera bly, these supports are essentially distributed around the circumference in an equidistant manner.

Preferably, the circumferential length of each cut is 5 to 25%, preferably 10 to 20% of the circumference of the packag ing. This provides sufficient axial support of the rim of the optical element while maintaining a sufficient overall strength of the packaging. Of course, a circumferential cut having a length of the maximum 25% can only be used for a packaging having less than four pairs of parallel circumferen tial cuts around the circumference of the packaging.

In a preferred embodiment, the axial distance between the two cuts of a pair of cuts is 15 to 60%, preferably 30 to 40% of the axial distance between two axial supports for two neigh boring optical elements. This feature describes the relative axial length of the cutout portions protruding radially in wards and the paper sheet material portions between two such cutout portions. This relation provides for sufficient overall mechanical strength of the packaging. The paper sheet material portions between two such cutout portions must be adapted to the maximum axial space requirement of the optical elements. A second aspect of the invention is a method for packing opti cal elements, in particular spectacle lenses, into a packag ing, comprising the steps of: a.forming an essentially cylindrical packaging from a flexible sheet material for radially holding the circumference of the optical element, b.forming radially inward protruding sheet material portions in the sheet material for axial support of the rim of the first and lowermost optical element, c.inserting the first and lowermost optical element into the packaging, d.forming radially inward protruding paper sheet mate rial portions for axial support of the rim of the second optical element, e.inserting the second optical element into the pack aging, f.repeating steps d. and e. for each subsequent opti cal element.

In this method, the packaging is formed first, and the optical elements are inserted into this packaging sequentially.

A third aspect of the invention is a method for packing opti cal elements, in particular spectacle lenses, into a packag ing, comprising the steps of: a.placing an essentially rectangular sheet for radi ally holding the circumference of the optical ele ment into a half-shell having a curvature essen tially corresponding to the circumferential curva ture of the optical elements, b.placing the optical elements into the sheet so that the rims of the optical elements are partially sup ported by the sheet laid out on the surface of the half-shell, c.forming radially inward protruding sheet material portions for axial support of the rim of the optical elements over a part of the circumference of the packaging, d.closing the packing by joining the opposing edges of the essentially rectangular sheet, e.forming radially inward protruding sheet material portions in the sheet material for axial support of the rim of the optical elements over the remaining part of the circumference of the packaging.

In this method, the packaging placed into the half-shell is filled first with optical elements and subsequently closed by joining the opposing edges of the essentially rectangular sheet. In this method, steps b. and c. can either be carried out sequentially for each optical element (after placing the optical element into the half-shell, the corresponding radi ally inward protruding sheet material portions for this opti cal element are formed), or, alternatively, multiple optical elements or all optical elements can be inserted in step b. and the corresponding radially inward protruding sheet mate rial portions for these optical elements formed subsequently in step c.

Both methods according to the second and third aspects of the invention can be carried out either manually or mechani cally/automatically using appropriate machines or robots.

In both methods, the handling and manipulating of the optical elements can be carried out with a suction device. A suction device allows precise and mechanically gentle handling of the optical elements.

The methods of the present invention are preferably carried out so that a packaging as previously described and claimed in use claims 1 to 11 is formed.

The sheet material used in the claimed methods preferably com prises or consists of paper, cardboard, and/or a polymeric ma terial. Paper and/or cardboard are preferred. Preferred values for the specific weight of paper or cardboard are 80 to 500 g/m ² , preferably 120 to 250 g/m ² . These sheet materials are readily available, easy to handle and recyclable.

In a preferred embodiment the sheet material is a paper sheet material. A specific weight of the paper may be between 20 g/m ² and 225 g/m ² , preferably between 60 g/m ² and 180 g/m ² , more preferably between 80 g/m ² and 140 g/m ² . Such a paper is readily available, easy to handle and recyclable. The paper sheet material preferably consists essentially or entirely of paper. However, the paper sheet material may also comprise pa per which is coated with a coating material such as a poly meric material. In a particularly preferred embodiment, the method uses an es sentially rectangular sheet with two opposing edges (sides) joined together so as to form an essentially cylindrical pack aging. For joining the edges together, the rectangular sheet may comprise appropriate adhesive stripes or other appropriate affixing means. The rectangular sheets may be stored as flat sheets prior to use and assembled to form an essentially cy lindrical packaging during the packing process. In one embodi ment, an essentially rectangular sheet can be an isosceles trapezoid and an essentially cylindrical packaging can be in a form of oval.

In one embodiment of the methods, the axial distance between two axial supports for two neighboring optical elements is adapted to the maximum axial space requirement of an optical element.

In a preferred embodiment, the packaging formed according to the claimed methods comprises axial and/or radial perforations for opening the packaging. The packaging may comprise more than one such radial perforation, and may comprise a radial perforation between each of the adjacent neighboring optical elements.

In a particularly preferred embodiment, the sheet used in the claimed methods comprises pairs of parallel circumferential cuts, each pair enclosing a sheet portion radially protruding inward (cutout portion) for providing axial support of the rim of the optical element.

This embodiment enables to provide the radially inward pro truding sheet material portions from the simple flat sheet ma terial. A pair of parallel circumferential cuts encloses a circumferential, essentially rectangular sheet material por tion separated from the remaining sheet material through the circumferential cuts (in axial direction) and being connected to the remaining sheet material at its circumferential end portions. When the complete sheet material forms an essen tially cylindrical packaging, this sheet material portion can be pushed radially inwards and remains in this position due to the tension of the sheet material. The cutout sheet material portions flexed radially inwards therefore provides axial sup port for the rims of the optical elements in a simple and ef ficient manner. The circumferential cuts and the corresponding sheet portions can easily be adapted to provide axial support for optical elements of varying thickness.

Preferably, the packaging formed according to the claimed methods comprises at least two, preferably at least three, further preferred four pairs of parallel circumferential cuts around the circumference of the packaging. This provides axial support of the rim of the optical elements in at least two, preferably three, further preferred four areas around the cir cumference of the optical element. Preferably, these supports are essentially distributed around the circumference in an equidistant manner.

Preferably, the circumferential length of each cut is 5 to 25%, preferably 10 to 20% of the circumference of the packag ing. This provides sufficient axial support of the rim of the optical element while maintaining a sufficient overall strength of the packaging. Of course, a circumferential cut having a length of the maximum 25% can only be used for a packaging having less than four pairs of parallel circumferen tial cuts around the circumference of the packaging. In a preferred embodiment, the axial distance between the two cuts of a pair of cuts is 15 to 60%, preferably 30 to 40% of the axial distance between two axial supports for two neigh boring optical elements. This feature describes the relative axial length of the cutout portions protruding radially in wards and the sheet material portions between two such cutout portions. This relation provides for sufficient overall me chanical strength of the packaging. The sheet material por tions between two such cutout portions must be adapted to the maximum axial space requirement of the optical elements.

As indicated above, the packaging according to the invention typically is essentially cylindrical according to the circum ferential shape of the optical elements.

Optionally, the packaging might be wrapped into a protective film preferably made from a suitable polymeric material. A protective film provides improved protection against the envi ronment and increases mechanical stability.

Optionally, it is possible to seal one or both axial ends of the packaging with an axial cover. Such an axial cover prefer ably is made from a material with sufficient rigidity, e.g. plastics or cardboard. The axial cover can be affixed to the packaging using an appropriate adhesive, stapling and/or a friction and/or form fit. The axial cover also increases me chanical stability and improves protection against the envi ronment .

According to a further preferred embodiment, in a subsequent step this packaging is inserted into an outer packaging. This outer packaging can provide additional mechanical protection and preferably comprises a rectangular cube shape, which makes it easier to store and pile such outer packagings.

An outer packaging comprising a packaging as previously de fined is further subject matter of the invention.

According to another aspect of the present invention a packag ing for a plurality of spectacle lenses is provided, wherein the packaging comprises a flexible sheet material for radially holding the lens circumference, the flexible sheet material further comprising radially inward protruding sheet material portions for axial support of the lens rim. This aspect may be further developed by the features which have already been de scribed in relation with the inventive use and the inventive methods described herein.

Embodiments of the invention are described with reference to the attached drawings. These drawings show:

Fig.l: Flexible sheet with cutout portions for axial support of the optical elements;

Fig.2: Longitudinal cross-section of the packaging with in serted optical elements:

Fig.3: Cross section showing schematically the concept of the cutout portions providing axial support for the optical elements;

Fig.4: Schematically the steps of a manual method for pack ing and unpacking optical elements; Fig.5: Schematically the steps of a first mechanical method for packing and unpacking optical elements;

Fig.6: Schematically the steps of a second mechanical method for packing and unpacking optical elements.

Fig.l shows a front view of a rectangular sheet 1 made from paper material with sufficient flexibility and tensile strength. Along one edge, the sheet comprises an adhesive strip 2 which can be used to join this edge with the opposing edge of the sheet to a cylinder. The sheet comprises pairs of parallel cuts 3, 4 in circumferential direction x. Between each pair, a cutout portion 5 is formed.

As shown in Fig.3, once the sheet has been formed into cylin drical shape, each cutout portion 5 can be flexed inwards by applying a force in the direction of the arrow 7. Once the cutout portion 5 has been flexed inward, it remains in this position thanks to the tensile strength of the sheet material. Each cutout portion 5 then provides an axial support for an optical element 6, more specifically for a spectacle lens.

As shown in Fig.l, the axial distance in the direction y be tween two cutout portions 5 corresponds approximately to the maximum axial space requirement of a spectacle lens 6 to be inserted into the packaging. The axial space requirement is determined by both the maximum thickness and the curvature of a spectacle lens.

Fig.2 shows a longitudinal cross-section of a partially filled packaging according to the invention. It is shown how inward flexed cutout portions 5 provide axial support of a spectacle lens 6. At the same time, the sheet material radially holds the lens circumference.

By appropriate positioning of the cuts 3, 4 in the paper, the distance can be optimally adjusted depending on the lens thickness and axial space requirement respectively. In the case of thin lenses, choosing a smaller distance leads to less packaging volume.

In addition to the use of paper sheets with predefined cuts, the individual introduction of the cuts by an appropriate tool (e.g. laser or cutting knife) is another variant.

There is no need for inlays to protect the glasses. In the case of extremely convex glasses, contact with the neighboring glass can be avoided by choosing a sufficient axial length of the cutout portion 5 so as to provide adequate axial distance between adjacent lenses.

The invention typically requires only one third of the packag ing material which is required for individual packagings of the prior art. As explained above, no inlays are required and thus no material for such inlay is necessary.

Extra stickers for the specification of glass data are not necessary. All the necessary information can be printed on the material sheet before it becomes a roll.

Perforations or similar weakenings provided in the sheet help to make it easier to remove the glasses from the roll. Depend ing on the positioning, the perforation can be optimized for the removal of an individual glass (radial or circumferential perforation) or the complete opening of the packaging (axial perforation).

Fig.4 schematically shows a manual method for packing and un packing of lenses 6.

In step A, the sheet material 1 is formed to a cylindrical roll by adhesive connection of the corresponding opposing edges.

In step B, the spectacle lenses 6 are sequentially manually inserted into the roll.

In step C, four cutout portions 5 are pushed radially inwards so as to provide axial support for the inserted spectacle lenses 6.

In step D, each packaging (roll) is inserted into an outer packaging 8 for further transport and storage.

Step E shows the manual removal of single lenses from a pack aging comprising circumferential perforations 9. The lens with the corresponding part of the packaging can be torn apart from the packaging via the corresponding perforation 9.

Step F shows how another variant of the packaging can be opened using an axial perforation 10 for subsequent removal of all glasses.

Fig.5 schematically shows a first mechanical method for pack ing and unpacking of lenses. The sheet material 1 is formed to a cylindrical roll by adhe sive connection of the corresponding opposing edges. In step A, the spectacle lenses 6 are sequentially mechanically in serted into the roll. This is done using a robot 11 comprising a suction device 12 attached to an arm 13.

In step B, the cutout portions 5 for the lens previously in serted into the roll are pushed radially inwards using the ro bot 11 comprising an arm 13 and a suction device 12 so as to provide axial support for the inserted spectacle lenses 6. Steps A and B are repeated for each lens inserted into the roll.

Each packaging (roll), after having been filled with lenses, is taken up by a robot 14 comprising a four finger gripper 15 (Step C), and is inserted into an outer packaging 8 for fur ther transport and storage (Step D).

For mechanical removal of single lenses from a packaging com prising circumferential perforations 9, the packaging is taken out of the outer packaging using a robot 14. A single lens with the corresponding part of the packaging can be torn apart from the packaging at the corresponding perforation 9 using the four finger gripper 15 (Step E). In Step F, the paper of the packaging is removed from the lens.

Fig.6 schematically shows a second mechanical method for pack ing and unpacking of lenses.

The sheet material 1 is placed into a half-shell 16 having a curvature essentially corresponding to the circumferential curvature of the spectacle lenses (Step A). This is done using a robot 11 comprising a suction device 12 attached to an arm 13.

In step B, the spectacle lenses 6 are sequentially mechani cally inserted into the roll using the robot ll/suction device 12. After each insertion of a lens, three of four cutout por tions 5 along the circumference are pushed radially inwards using appropriate mechanical devices of the half-shell 16 (not shown in the drawing). These three cutout portions are the cutout portions placed at the bottom and close to the edges of the half-shell 16.

After placing all lenses into the packaging, the sheet mate rial is formed to a cylindrical roll by adhesive connection of the corresponding opposing edges in Step C. The fourth cutout portions placed in the area of the top of the roll are also pushed radially inwards after closing the roll.

Each packaging (roll), after having been filled with lenses, is taken up by a robot 14 comprising a four finger gripper 15 (Step D), and is inserted into an outer packaging 8 for fur ther transport and storage (Step E).

For mechanical removal of the lenses from a packaging compris ing an axial perforation 10, the packaging is taken out of the outer packaging using a robot 14 (Step F) and placed into a half-shell 16. Preferably the robot 14 uses a four finger gripper for this task.

A robot comprising a finger gripper 17 (preferably a two fin ger gripper) opens the packaging tearing apart the axial per foration 10 (Step G). In Step H, the lenses 6 are sequentially removed from packag ing using the suction device 12 of the robot.