MXPA99006917A - Method and apparatus for the thermal bonding of a base part of a packaging with a cover film, and a method and apparatus for packaging contact lenses - Google Patents

Abstract

In a method for the thermal bonding of a base part (3) of a packaging with a cover film (F), especially for the welding or sealing of a base part of a packaging for contact lenses with a cover film, the contact surface of the base part (3) facing the cover film (F) and the corresponding contact surface of the cover film (F) facing the base part are mechanically pressed against one another along a join. While the mechanical pressure is being generated along the join, heat is simultaneously caused to act on the join, so that the contact surfaces of base part (3) and cover film (F) are thermally bonded to one another along the join. For the purpose of generating the mechanical pressure and causing heat to act on the join there is used a contact plate (70) of low heat capacity which, during the thermal bonding, is pressed against the surface of the cover film (F) remote from the contact surface. The temperature of the contact plate is measured in the immediate vicinity of the cover film, and in the event of the measured temperature deviating from a predetermined tolerance range around a desired temperature, the temperature of the contact plate (70) is within a very short time adjusted so that it again lies within the predetermined tolerance range around the desired temperature.

Description

METHOD AND APPARATUS FOR THE THERMAL LINK OF A BASE PART OF A PACKAGING WITH A COVER FILM, AND A METHOD AND APPARATUS FOR PACKAGING CONTACT LENSES The invention relates to a method and apparatus for thermally linking a base part of a package with a cover film, and to a method and apparatus for packaging contact lenses according to the preamble of the independent patent claims. respective. The methods and apparatus of the aforementioned kind are already used today in a large number of variants, where a specific article, especially a contact lens, is to be packed in a hermetically sealed manner in a package. This is generally done by inucing a contact lens into a depression of a base part of a package, dosing a predetermined amount of a preservative solution into the depression, then placing on the package a cover film that it can be thermally bonded to the base part of the package, and finally thermally bonding the cover film to the package. The operation can then be followed by sterilization. The packaging containing the contact lens can then be delivered to the client or to the optometrist or the ophthalmologist. It will be readily apparent that, especially in the field of contact lens packaging, but also, for example, in the fields of food materials, pharmaceuticals, medicinal articles, and some other fields, certain packaging demands are made. These demands can be related especially to the sealing (against leakage or against the entry of foreign substances) of the packaging, but can also be related to the adhesion of the cover film to the base part of the packaging, with the impermeability of the packaging to certain substances, or with the force required to remove the film (separation force). In order for a package to satisfy these demands, the parameters during the thermal link of the base part and the cover film (duration, pressure, temperature) must always remain within predetermined limits. In packaging technology, there are different techniques for joining two materials to each other. These include, among others, adhesive bonding with hot or cold glue, welding, and "sealing". While in the adhesive bond the joint is generally only in the form of a point or a line, the welding or sealing is especially suitable also for joints made over a larger area. The difference between welding and sealing is in the nature and characteristics of the materials to be joined. In packaging technology, "welding" refers to when two identical materials are joined together under the action of pressure and temperature (without involving any other materials). However, in the case of "sealing", at least one of the associated materials is provided with a sealable coating. Therefore, in both methods, the bone materials are joined together under the action of pressure and temperature, but in the case of sealing, the materials that are to be joined to each other are generally different. Sealing is most commonly used in the field of blister packs, where "stretchable plastic films, primarily transparent, are sealed to a cardboard card, the carton having generally been coated with a sealable sealant coating, or For example, with a polyethylene film, it is customary in contact lens packaging that a base part, which can be produced, for example, by injection molding, is bonded to a film that has been covered. with a sealable coating The bonding of the base part and the cover film takes place after the lens has been inuced into a suitable depression in the base part, and after a preservative solution, for example saline, has been dosed in the depression. This package is described, for example, in European Patent Number EP-A-0,680,895. It is said that the packaging will seal against the entry of foreign substances from the outside, and it is said that it prevents the saline solution from being flushed outward. The adhesion of the cover film to the package must be such that the package is not damaged during sterilization, which normally takes place in an autoclave. In addition, the separation force required to remove the film from the base part, that is, to open the package, must not exceed a maximum value, so that the user can open the package with an amount of effort reasonable. Known apparatuses for the thermal bonding of a base part to a cover film, as are used, for example, in the sealing of blister packages, are essentially constructed as follows: a support device or ditch is provided, with a number of depressions to accommodate the base parts. The support device is connected to an adjustment device, which can be moved to a link unit, for example with the aid of a pneumatic pulse element. The link unit comprises a bulk metal heating plate having a large heat capacity, and is also configured to move towards the support device or the gutter with the aid of an additional adjustment unit, which may include, for example, a pneumatic pulse element. In the heating plate of the linking unit, a number of heating elements are configured, which heat the heating plate to a predetermined temperature. A sealing plate is releasably connected to the heating plate underneath the heating plate, that is to say facing the support device or the gutter. The sealing plate is provided with a number of contact elements, called "dice". The end face of the dice constitutes the actual pressure face that comes into contact with the cover film during sealing. This pressure face also substantially determines the shape of the joint along which the cover film is sealed to the base part. Temperature sensors are provided on the heating plate and on the sealing plate. These temperature sensors are connected to a regulating element, which is used to control the time during which the heating elements are activated. This known apparatus operates as follows: the base parts are held ready in the depressions of the support device (gutter), and the cover film is placed on these base portions. Using the adjustment units to move the support device (gutter) and the linking unit, the latter move towards each other, until the pressure faces of the dice compress the cover film against the base parts at a time. pressure previously determined. As the film is compressed against the base part by means of the dice, the sealable coating is heated, and under the action of pressure and temperature, the base part and the cover film are bonded together. The known apparatus "is basically perfectly efficient, but still has disadvantages, especially with respect to the aforementioned demands that must be met when contact lenses are packed in. The movement of the support device and / or the link unit must be such that the surfaces of the supporting device and the linking unit, which transfer the sealing pressure to the packing, are exactly parallel to each other, even very slight fluctuations can result in significant variations in the sealing pressure, and - consequently, a seal that does not satisfy the mentioned demands, since the sealing pressure is applied directly by means of the adjustment units, the adjustment unit in question, or its impulse element must operate in a very precise manner. According to the nature of the adjustment unit (mechanical, hydraulic, or as mentioned above, pneumatic), the control element required for that purpose can be very expensive. The heating elements in the heating plate and in the pressure face, ie, the end face of the dice) are at a relatively large distance apart. As a result of the large heat capacity (inertia) of the bulky heating plate, and as a result of the heat capacity (inertia) of the sealing plate, a relatively long time elapses before a change in the pressure face temperature. Therefore, a rapid change in temperature is not possible at the point that is crucial to the quality of the seal, that is, on the pressure face. In addition, the temperature on the pressure face also continues to rise for a considerable period, when the heating elements are deactivated again after a heating operation. Even with the help of temperature sensors, it is very difficult to achieve precise regulation of the temperature on the pressure face (the end face of the die). If the heat supply is regulated exclusively on the basis of the temperature sensor that is configured on the sealing plate as close as possible to the dice, the heating plate / sealing plate system has a tendency to "overdraw", due to which has a high inertia. Accordingly, for example, if the temperature sensor indicates that the temperature at the temperature sensor site (ie, near the die) is too low, the heating elements receive the signal to heat. However, since the heating plate / sealing plate system has a high inertia, the temperature at the temperature sensor site does not rise immediately. As a consequence, the temperature sensor indicates that further heating is required, eg as a result of the heating plate overheating, and even when, after a while, the temperature at the temperature sensor site has reached the desired temperature , the heat previously supplied to the heating plate will result in the temperature of the heating plate being transmitted to the sealing plate, and consequently, to the dies and their pressure faces, resulting in an excessive increase in temperature (over-shot). However, if the heat supply is regulated exclusively on the basis of the temperature sensor configured on the heating plate, then, although the heating elements can be adjusted in a relatively precise manner (and consequently, damage can be avoided) thermal to the heating elements (burned)), the actual temperature on the pressure face will be a little lower than the temperature in the heating elements. If the heat supply is regulated with the help of both temperature sensors, the heating plate / sealing plate system will still have a tendency to overdraw as a result of its inertia. If transient behavior is recognized and taken into account when heat is supplied, that is, if an attempt is made to avoid overshooting, a rapid change in temperature at the crucial site, ie on the face, will not be possible again. of pressure (end face of the dice), because, as a result of the large heat capacity (inertia), the heat supply must take place correspondingly in a slower manner. If a heating element fails, this will not necessarily be noticed, because the other heating elements will assume the function of the defective heating element. However, the temperature distribution in the different pressure faces (end faces of the dice) will therefore be much less accurate, resulting in seals that do not meet the aforementioned demands. However, this can not be tolerated, particularly in the case of fully automated production and packaging of large numbers of contact lenses. Accordingly, it is an object of the invention to propose a method and apparatus for the thermal bonding of a base part and a cover film of a package, especially a method for welding or sealing a base part and a cover film of a contact lens package, which does not have the aforementioned disadvantages. A further objective is to propose a method for packaging contact lenses, with which it is possible to obtain packaging that meets the mentioned demands, even in the case of a fully automated production and packaging of a large number of contact lenses. In the thermal bonding method according to the invention, therefore, for the purpose of generating the mechanical pressure, and causing the heat to act on the joint, a contact plate of a low heat capacity is used which, during the Thermal bonding is compressed against the surface of the remote cover film of the contact surface. In addition, the temperature of the contact plate is measured in the immediate vicinity of the cover film. In the event that the measured temperature of a predetermined tolerance range is shifted around a desired temperature, the temperature of the contact plate is adjusted within a very short time, so that it is again within the range of Pre-determined tolerance around the desired temperature This is possible only as a result of the low heat capacity of the contact plate which, according to the above, only has a low degree of inertia.In other words: when the measured temperature in the vicinity of the cover film it is outside the tolerance range around the desired temperature, and according to the above, for example, additional heating is performed, the temperature in the vicinity of the cover film is returned quickly to the tolerance range, the large-scale overshoot is eliminated in the same way. suitable variants of the method according to the invention. These refer, for example, to the characteristic that, during thermal bonding, a substantially uniform mechanical pressure previously determined is generated throughout the joint. This can be achieved, for example, by using a pivotally mounted die to generate the substantially uniform mechanical pressure along the joint, the contact plate being configured on the die end facing the base part of the package. For this purpose, it is possible to use a die that is mounted to be able to move against the force of a spring towards a frame configured in a fixed spatial position. - Additional convenient variants of the method refer to the following characteristics: a number of base parts are kept ready simultaneously in a support device; a number of pivotally mounted dice are used on a common fixed frame; and a number of base portions are thermally bonded to a cover film simultaneously, by moving the support device towards the dice or towards the frame on which the dice are mounted, in such a way that, as a result of the transmission of heat and pressure to the contact surfaces of the base part and the cover film, the latter being thermally bonded to each other along the joint. The apparatus according to the invention is distinguished by the fact that the die has a contact plate that can be heated, of a low heat capacity, which is configured on the end of the die facing the support device, and during thermal bonding, it compresses against the surface of the remote cover film of the contact surface along the joint. On the contact plate is configured, in the immediate vicinity of the pressing face compressing against the cover film, a temperature sensor, which measures the temperature of the contact plate, and which, in the case that the temperature deviates from a pre-determined tolerance range around the desired temperature, immediately generates a corresponding signal, and passes it to a fast regulating element that immediately regulates the temperature of the contact plate, in such a way that again within the previously determined tolerance range. The advantages correspond to the advantages already mentioned in relation to the method according to the invention. The convenient modalities will be apparent from the characteristics of the dependent claims. These refer, for example, to the fact that the die can be pivotally mounted. In addition, the die may have on the face of the remote contact plate of the support device, a heating element, which warms the contact plate, and an insulating body, in order that substantially all the heat generated by the heating element is transmitted to the contact plate and not to the environment. The heating element can be constructed in the form of a thin ceramic plate, on which are provided, on the one hand, a resistance heating device having two metal connection pads, and on the other hand, resistive lines which Connect these two connecting pads to one another in the manner of a conductor. This heating configuration is especially structurally simple, and it is also reliable. The power supply for supplying electrical voltage to the resistance heating device comprises, in one embodiment, two elastic metal bolts extending through the insulating body, and the ends of which are in contact with the connection pads of the device. resistance heating. "The additional modalities refer to the fact that the die is mounted to be able to move against the force of a spring towards a frame configured in a fixed spatial position.The additional modalities are distinguished by the provision of a number of dice that are mounted on In addition, the support device has a number of depressions to accommodate the base portions of a package, and the support device, together with all the base portions, can be moved by means of an adjustment unit. towards the dice and towards the frame on which the dice are mounted The method for packing contact lenses according to the invention is distinguished by the fact that, for the thermal bonding of a base part and cover film, use is made of one of the aforementioned methods for the terminating link of the base part and the cover film, in a convenient variant, after the pair has been thermally bonded base and the cover film, the packaging thus produced is sterilized. Preferably, the packaging is transported to an autoclave for sterilization. Before sterilization, first a number of packages can be transported to a carousel, and then the packages contained in the carousel can be sterilized together. The contact lens packaging apparatus according to the invention is distinguished by the fact that the device used for the thermal bonding of the base part and the cover film is one of the above mentioned apparatus modalities for the thermal bonding of the base part and the cover film. In one embodiment, the apparatus includes a device for sterilizing the package after the base portion and the cover film have been bonded. The device for sterilizing the package can be, for example, an autoclave. A carousel can be provided, to which a number of packages are transported before sterilization, and then the carousel is introduced into the autoclave for the purpose of sterilizing the packages. The invention will be described in more detail below, with reference to the drawing, which is partly in the form of a diagram and / or in section: Figure 1 shows an embodiment of a support device for accommodating the base portions of a package for contact lenses. Figure 2 shows a modality of a base portion of a contact lens package, which can be accommodated by the support device according to Figure 1. Figure 3 shows one embodiment of an apparatus for packaging contact lenses.

Figure 4 shows detail IV of Figure 3 for the purpose of explaining the introduction of contact lenses in the base portions of the packages. Figure 5 shows detail V of Figure 3, for the purpose of explaining the entry of the support device into the apparatus for linking the base part and the cover film. Figure 6 shows an embodiment of the apparatus for attaching the base portions of a contact lens pack to a cover film, in the rest position and in the position in which the base portions are bonded to the cover film . Figure 7 shows the detail VII of Figure 6. Figure 8 shows a modality of a die and its assembly configuration. Figure 9 shows a view of the die contact plate from below. Figure 10 shows a view of the die contact plate from above, with the ceramic heating plate adhesively bonded thereon. Figure 11 shows a section according to line XI-XI of Figure 10; and Figure 12 shows the embodiment of the apparatus for linking the base parts and the cover film shown in Figure 6, but in a sectional view in the transport direction. The embodiment of a support device shown in Figure 1 essentially comprises a support (for example of metal) 1, on which a number of individual support elements 2 are formed in a well-defined position; in this case, for example, 5 support elements 2 are formed on the support 1. The support elements can be made, for example, of anodized aluminum or of chrome-plated steel. Each clamp of the support elements 2 is suitable for accommodating a base part of a contact lens package. It is also possible for the support 1 and the support elements 2 to form a single component together. This base portion 3, which can be accommodated by the support elements 2, is shown in Figure 2. The base portions 3, which can be produced, for example by injection molding, have a drop-shaped depression. , where the contact lens to be packaged is introduced, and then a preservative solution, for example saline, is dosed. A cover film is then placed on the base part 3, and is bonded thereto. The manner in which the connection of the base part and the cover film can be effected will be described in more detail below. Figure 3 shows, in a diagrammatic form, an apparatus for packaging contact lenses, or their essential parts. Figure 4 and Figure 5 show additional details of that apparatus. For simplicity, the following explanation refers only to a transport track in the description of the manner in which the contact lenses are introduced into the base portions, and the manner in which the subsequent packaging is made. In practice, a number of these transport tracks can be configured, for example 5 of these transport tracks, parallel to each other. First, the lens of. contact that adheres to a fastener 4, or to the convex surface 4 of a clamping arm 41 (Figure 4), as a result, for example, of a partial vacuum generated (in the clamping arm or in a channel provided in the clamping arm ) with the aid of which the contact lens is sucked against the convex surface 40, it is transported over a depression 30 in the base part 3. At the moment when the lens or the contact lenses are going to be deposited or deposited. in the depressions 30, an overpressure is generated instead of the partial vacuum (in the clamping arm or in the channel), with the help of which the contact lens or the contact lenses are released from the convex surface 40, in such a way that they can slide or fall from a very small height (which is very exaggerated in Figure 4, but is therefore easier to see) in the respective depression 30. The base part 3 itself is configured in a supporting element 2 of a support 1 (as already explained with r reference to Figure 1), and this support 1 is located in a well defined position in relation to the position of the fastener 4 of the fastening arm 41. Figure 4 shows two of these supports 1, which are configured to follow one after the other on a track. Above the support 1 the fastener 4 is shown with the two clamping arms 41 and the convex surfaces 40. In Figure 4 as in Figure 3, the transport direction on which the supports 1 are transported, is indicated by the arrow T Also in Figure 4 the stops 5 that can be moved up and down are shown. The support 1, in a corresponding manner, has, on its lower side, a groove 10 (see also Figure 1), which extends in the direction of transport over virtually the entire length of the support 1. Only at the end front 11 (seen in the direction of transport) of the support 1, the groove 10 does not extend as far as the front end 11 of the support, since the leading end 11 impacts against the stop 5 in question, and stops in a fixed position by means of that stop 5, until the stop moves from the upper position to the lower position. As soon as the stop 5 contacted by the front end 11 of the support 1 moves to the lower position, the support 1 moves in the transport direction T, until its front end 11 impacts against the next stop 5 located in the top position. Then the stop 5 previously moved downwards can be moved upwards again, since it does not prevent the additional transport of the support 1, because in its upper position it projects into the groove 10. We will assume for greater simplicity, that (unlike the situation shown in Figure 4), there is no support 1 in place, and that a support 1 is entering from the left side. Now, several situations can arise. In the first case, there is a flawless contact lens adhering to the right clamping arm 41, or to its convex surface 40, and according to the foregoing, it is to be deposited in the depression 30 of the base part 3. In that case , the stop configured on the left end, moves to the lower position, while the other stops, meanwhile, are in the upper position. Then the support 1 is transported in the transport direction T, until its front end 11 impacts against the first (seen from the left) stop 5 which is in the upper position. Since the stop configured at the left end is in the lower position when the support 1 enters, the leading end 11 of the support 1 hits against the second stop (seen from the left). Under the two clamping arms 41, two base portions 3 (Figure 2) of the package are now formed, with the corresponding depressions 30. Now the flawless contact lenses can be adhering to the two clamping arms 41, or to the convex surfaces 40 of them. If this is the case, both contact lenses are deposited (as a result of which an overpressure is generated in the clamping arms or in the channels thereof) in the respective depressions 30 of the base 3 parts of the package. Then a check is made to establish whether contact lenses are adhering without defects to the two clamping arms that come to rest on top of support 1 in the next step. If there is a flawless contact lens adhering to at least the right clamp arm or the convex surface thereof (regardless of whether or not there is a flawless contact lens adhering to the left clamp arm), then the second and third stops (seen from the left) they move to the lower position, in such a way that the support moves two base parts forward in the transport direction T, until its front end impacts against the fourth stop from the left. If there is a defective contact lens adhering only to the left support arm, then only the second stop (but not the third stop) is moved from the left to the lower position, and the support is transported only one base part forward in the transport direction, until the front end of the support impacts against the third top of the left. However, if there are no defective contact lenses adhering to either of the two holding arms, then the position of the stops remains unchanged, and no contact lenses are deposited (depressions in the base portions that are located under the clamping arms in that case, of course, are occupied by contact lenses without defects). Then a check is made again to establish if there are contact lenses without defects by adhering to the two clamping arms located above the support in the next step, and the stops move, or do not move, according to the same. Accordingly, a contact lens without defects is always introduced towards the front (seen in the direction of transport) of the depressions in a base part, which is not yet occupied by a contact lens. According to the view of Figure 4, therefore, contact lenses are located without defects in the first four base portions (seen in the transport direction) of the package configured in the right support, or rather in the depressions of those base parts. If it is now assumed that contact lenses have been adhered without flaws to both clamping arms 41, or to the convex surfaces 40 thereof, and in the same manner have been deposited in the depressions, then a contact lens will be located without defects in each base part on the right support. In addition, the first base part on the left support will also contain a defective contact lens. While the stop configured on the right end then moves to the lower position accordingly, and in accordance with the same allows the right support to be further transported to a station where a preservative solution, for example saline solution, is dosed in the individual depressions, a check is also made to establish if there are contact lenses without defects by adhering to the two holding arms located above the support to be provided with contact lenses in the next step. Then, as explained above, the stops move again, or do not move, according to the same. When all the base parts 3 on a support 1 have been provided with contact lenses without defects, that support is additionally transported, and - as already mentioned - a predetermined volume of a preservative solution, for example saline solution, is dosed, in each of the depressions. This is indicated symbolically in Figure 3 by an arrow S. In the course of its transport in the transport direction T, the support, together with the base parts provided with contact lenses, where saline has also been dosed, then passes to a station or device 6, where, firstly, , a continuous piece of cover film F is stamped, and placed on the base parts 3, which is symbolized by a corresponding arrow in Figure 3, and in which device 6, secondly, the film is subsequently bonded of cover F to the base parts 3. - In Figure 5, which shows detail V of Figure 3 on an amplified scale, it will be seen that support 1, which has passed to device 6, in the course of its travel in direction of transport T, hits against a stop 60, which can be moved up or down in the same way. In the upper position, as shown in Figure 5, the stop 60 serves to fix the supports 1 entering the device 6 temporarily in a well-defined position. In each of the support elements 2 on the support 1 (Figure 1), a base part 3 is formed, whose depression 30 contains saline solution and a contact lens arranged in the saline solution. In addition, a continuous piece of cover film F is spread over all the base portions 3 of a support 1. In other words: the cover film F can now be linked to the base part 3. In order to link the base parts 3, of which-there are 5 in the example shown, to the cover film F, the entire support 1 is lifted, for example pneumatically, and compressed against a corresponding number of individual dice 7. This can be see in principle starting from the two halves of Figure 6. Figure 6 shows a diagrammatic section through the device 6 perpendicular to the transport direction T, the device being seen in the transport direction accordingly. It will be seen from this view, that here 5 transport tracks are configured parallel to one another, and that on each of these transport tracks, a support 1 having the corresponding base parts is located in the device 6. - However, although in the right half of Figure 6 the supports 1 are in the lower position, where consequently there is no contact between the cover film F and the dice 7, in the left half of Figure 6 the supports 1 They are in the top position. "This elevation of the supports 1 in the device 6 can be effected by means of a pneumatic pulse element 61. The dice 7 are mounted virtually in a fixed position on a common frame 62, in such a way that the elevation of the supports 1 by means of the pneumatic pulse element 61, causes the dice 7 to come into contact with the cover film F, and link the cover film F to the base part in a manner described in greater detail below. Figure 7 shows a package that can be obtained in this manner, which shows the detail VII of Figure 6. Figure 7 shows the support 1 with the groove 10, the support element 2 located on the support 1, and the base part 3 located therein, with the cover film F configured thereon. "^ Figure 8 shows a die 7 and its individual components. It will be seen that the die 7 has a contact plate 70 (for example made of steel), which has a low heat capacity, especially in comparison with the known bulky contact plates of high inertia, whose pressing face 700 comes into contact with the surface of the remote cover film of the base part during the thermal bonding of the base part and the cover film, and links the cover film to the base part along the pressure face 700. The shape of the pressure face, whose shape approximates that of a drop, can be seen in a particularly clear manner in Figure 9, where the contact plate is shown in a bottom view (the pressure face being shown). 700 in section). It will also be seen in Figure 8 that, on the rear face of the contact plate 70, a temperature sensor 71 is embedded very close to the pressing face 700 in an adhesive composition 72 having very good heat conductivity - ( for example, in a plastic that has the appropriate properties). The configuration of the temperature sensor 71 in the adhesive composition 72 having very good heat conductivity can be seen in a particularly clear manner in Figure 11, which shows a section through the contact plate 70. The temperature sensor 71 serves for measuring the temperature in the immediate vicinity of the pressure face, so that the temperature on the pressure face 700 is always accurately known, and it can be monitored or regulated. A temperature on the pressure face that is within a previously determined tolerance range (sealing temperature) is important for a reliable bond of the base part and the cover film, since this link, of course, must satisfy the high demands mentioned at the beginning.

According to Figure 8, a heating plate in the form of a ceramic plate 73 is also provided on the rear face of the contact plate 70. The ceramic plate 73 is adhesively bonded in a recess of the rear face of the contact plate "70, by means of an adhesive that has very good heat conductivity (the heat of the ceramic plate must be transmitted to the contact plate 70.) This can be clearly seen in Figure 10, which shows a horizontal view on the rear face of the contact plate 70. It will be seen that the adhesively bonded ceramic plate 73 has a number of electrically conductive connecting cushions, for example metal, 730, 731, 732, 733, 734, 735 The connecting cushions 734, 735 configured in the upper end of Figure 10 serve to collect an electrical signal corresponding to the temperature in the immediate vicinity of the pressing face 700. At the lower end of the plate d e ceramic 73, the two external connection cushions 730, 733 serve to supply energy, since the ceramic plate 73 is heated by means of conventional electrical heating elements (for example, a resistance heating device, not shown). The two internal connection cushions 731, 732 serve for measuring the temperature of the ceramic plate 73, to protect the latter from overheating. The respective electrical potentials of the connection pads can be collected with the help of elastic contact pins 74 (see Figure 8), and are supplied by means of the supply lines 740 to a fast regulating element (not shown); the energy supply for the heating device can also be effected by means of these elastic contact pins 74. Finally, the contact plate 70 is connected on its rear side to an insulating body 75, so as not to be transmitted the heat of the contact plate 70 to the environment. According to Figure 8, the die 7 also has a spherical union 76, around which the die is mounted to pivot against the force of a weak reset spring 77, which returns the die to the starting position. shown in Figure 8. This joint is especially important in order to generate a uniform pressure "along the junction between the base part and the cover film, since the precise temperature control - as described above - only It is a prerequisite of a good bond between the base part and the cover film: an additional prerequisite of a good link is as uniform a pressure as possible along the joint. of individual bases, with the cover film superimposed, in practice, they are not always configured exactly parallel to the face of pressure 700 of the die 7 for question, especially since there are always 5 of these It is base configured on a support at the same time, and linked to the cover film at the same time. On the other hand, the five links will satisfy the high demands mentioned at the beginning. If each die 7 is pivotally mounted, then, in the event that a base part is not configured exactly parallel to the die face 700 of the die, the die may pivot about the joint 76 when the base part is compressed with the cover film superimposed against the pressure face 700, such that, with the pivoted die, the pressure along the junction between the base part and the cover film is very uniform. Although in practice these pivoting movements are extremely small, they are important for a high quality link between the base part and the cover film. The joint 76 itself (or its extension) is rigidly connected to a pressure plate 78, which can be moved against the force "of two strong springs 79 (as compared to the spring 77) .The springs 79 are each configured around of a suspension rod connected to the pressure plate 78, and fastened between the fixed frame 62 and the pressure plate 78. Each die 7 (in the illustrated example 5 of these dice are provided along each track with the object of linking the five base portions 3 simultaneously located on a support 1 to the overlay cover films) is mounted independently on the common fixed frame 62. This configuration of five dice 7 along a track can be seen in the Figure 12 corresponding to a partially sectional view through the device 6, in the transport direction, Figure 12 shows the support 1 that has entered the device 6 and has found the stop 60, and on which they are configured. support elements, each having a base part with a contact lens in saline solution. The film that is going to link to the base parts remains on the base parts. Then the support 1 is lifted by means of the pneumatic pulse element 61 already described in the description of Figure 6, in such a way that the base parts with the superimposed film come into contact with the dice 7. When the support 1 is lifted , first of all, the individual dice pivot around the joint 76 if the base part in question is not exactly parallel to the pressure face 700, and then the pressure face 700 is compressed against the base part with the film of superimposed cover. As a result of the temperature, which is transmitted by means of the pressure face during a strictly predetermined period, and as a result of the pressure, the cover film is thermally bonded to the base part. The support 1 is raised by a predetermined distance rigidly, since, by virtue of the law governing the springs, the desired pressure force with which compresses the pressure face 700 against the base part and the cover film, is given by the distance that the support 1 rises. Once the support has been raised by the previously determined distance, it remains in that position for an exactly defined period of time (see the left half of Figure 6), linking the base parts and the cover film one to the other. The support 1 is then lowered again (right half of Figure 6), and the finished packages can be transported to an additional processing step. In the case described, since the film is in one piece and also extends over the intermediate regions between the individual base portions, the packages terminated in the embodiment shown are configurations of 5 interconnected packages. Then they can be transported to an additional processing step. In particular, for example, they can be transported to a carrousel, where a relatively large number of these configurations are collected, each of five packages, before the whole carrousel is transported to a sterilizing apparatus, for example an autoclave.

Claims (13)

1. A method for thermally bonding a base part (3) of a contact lens pack with a cover film (F), in which method the contact surface of the base part (3) facing the film of cover, and the corresponding contact surface of the cover film (F) facing the base part, each comprise a plastic, and, during the term bond, they are compressed mechanically against each other along a length of Union, and while the mechanical pressure is being generated along the joint, heat is simultaneously caused to act on the joint, such that the contact surfaces of the base part and the cover film are thermally bonded along the junction, where, for the purpose of generating the mechanical pressure and causing the heat to act on the joint, a contact plate (70) of a low heat capacity is used which, during the thermal bond, is compressed against surface of the remote cover film of the contact surface; The temperature of the contact plate (70) is measured in the immediate vicinity of the cover film (F); and in the case that the measured temperature is deflected from a predetermined tolerance range around a desired temperature, the temperature of the contact plate (70) is adjusted within a very short time, so that it again falls within the tolerance range previously determined around the desired temperature.

2. A method according to claim 1, wherein / during the thermal bonding, a substantially uniform mechanical pressure previously determined is generated throughout the joint. A method according to claim 2, wherein, for the purpose of generating the substantially uniform mechanical pressure along the joint, a pivotally mounted die (7) is used, the contact plate (70) being configured on the end of the die that faces the base part (3) of the package. 4. A method according to claim 3, wherein a die (7) is used which is mounted to be able to move against the force of a spring (79) towards a frame (62) configured in a fixed spatial position. 5. A method according to any of claims 1 to 4, wherein the number of base parts (3) is kept simultaneously in a support device (1, 2), a number of dice are used (7). ) pivotally mounted on a common fixed frame (62), and a number of the base parts (3) they are thermally bonded to a cover film (F), simultaneously moving the support device (1) towards the dice. 6. An apparatus for thermally bonding a base part (3) of a package with a cover film (F) especially for welding or sealing a base part of a contact lens pack with a film of cover, the base part (3) comprising its contact surface facing the cover film (F), and the cover film (F) on its contact surface facing the base part (3) each, a plastic, which has a support device "(1, 2) to accommodate the base part (3) of the package on which the cover film (F) extends, and which has a linking unit that it has a heatable die (7) which, during the thermal bonding of the base part and the cover film, cooperates with the support device (1,2), so that, by means of the die (7), both The mechanical pressure as heat acts on the contact surfaces along a joint, so that the part of base (3) and the cover film (F) are thermally bonded along the joint, wherein the die (7) has a heatable contact plate (70) of low heat capacity, which is configured on the end of the die (7) facing the support device (1,2) and, during the thermal link, compresses against the surface of the cover film (F) remote from the contact surface along the joint, and a temperature sensor (71) is configured on the contact plate (70) in the immediate vicinity of the pressure face (700), which compresses against the cover film, whose temperature sensor measures the temperature of the contact plate (70) and, in the event that the temperature deviates from a predetermined tolerance range around the desired temperature, immediately generates a corresponding signal, and passes it to a fast regulating element that immediately regulates the temperature of the contact plate (70), so that it is again within the previously determined tolerance range. 7. An apparatus according to claim 6, wherein the die (7) is pivotally mounted. 8. An apparatus according to claim 7, wherein ~ the die (7) has, on the face of the remote contact plate (70) of the support device (1,2), a heating element (73) , which heats the contact plate (70), and an insulating body (75), so that substantially all the heat generated by the heating element (73) is transmitted to the contact plate (70), and not to the environment. 9. An apparatus according to claim 8, wherein the heating element is constructed in the form of a thin ceramic plate (73), on which, on the one hand, a resistance heating device is provided. which has two metal connection pads (730, 733), and on the other hand, resistive lines connecting these two surfaces of contact with one another, in the manner of a conductor. An apparatus according to claim 9, wherein the power supply for supplying the resistance heating device with the electrical voltage comprises two elastic metal bolts (74) extending through the insulating body (75), and whose ends are in contact with the connection pads (730, 733) of the resistance heating device. 11. An apparatus according to any of claims 6 to 10, wherein the die (7) is mounted to be able to move against the force of a spring (79) towards a frame (62) configured in a fixed spatial position . 12. An apparatus according to any of claims 6 to 11, wherein a number of dice (7) are provided which are mounted on a common fixed frame (62); the support device (1, 2) has a number of depressions to accommodate the base portions (3) of a package; and the support device, together with all the base parts, can be moved by means of an adjustment unit (61) towards the dice and towards the frame (62) on which the dice are mounted. 1

3. A method for packaging contact lenses, in which method a contact lens is introduced into a depression (30) of a base part (3) of a package, a predetermined amount of a preservative solution (S) is dosed. in the depression, a cover film (F) is placed which can be thermally bonded to the base part of the package on the package, and then the cover film (F) is thermally bonded to the base part (3) at where a method according to any of claims 1 to 5 is used for the thermal bonding of the base part (3) and the cover film (F). A method according to claim 13, wherein, after the base part (3) and the cover film (F) have been thermally bonded, the package thus produced is sterilized. 15. A method according to claim 14, wherein the package is transported to an autoclave for sterilization. 16. A method according to claim 14 or 15, wherein a number of packages are first transported to a carousel prior to sterilization, and the packages contained in the carousel are then sterilized together. 17. An apparatus for packaging contact lenses, having a support device (1,2) for accommodating a base part (3) of a package, having a feeding device (4) for introducing a contact lens in the depression (30) of the base part (3) having a dosing device for dosing a conservative solution in the depression (30) of the base part, which has a device for applying and placing a cover film (F) on the base part (3) and having - a device (6) for thermally bonding the base part (3) and the cover film (F), wherein the device for thermally bonding the base part and the cover film is an apparatus according to any of claims 6 to 12. 18. An apparatus according to claim 17, which comprises a device for sterilizing the package after it is they have linked the base part (3) and the cover film (F). 19. An apparatus according to claim 18, wherein the device for sterilizing the package is an autoclave. An apparatus according to claim 18 or claim 19, wherein a carousel is provided to which a number of packages are transported before sterilization, and then the carousel is introduced into the autoclave for the purpose to sterilize the packaging.