Patent Description:
American patent <CIT> relates to a method for additively manufacturing an object, which allows easy separation of a hardened layer from a transparent reference plane formed by a so-called contact window, so that the layer currently being hardened in conjunction with the layer structure already produced is preserved in its original form, the necessary path of movement for separation being minimised and so the building time for each layer being reduced. For instance, a separating layer in the form of a transparent film is arranged between material and a transparent plate, or contact window, in such a way that the separating layer undergoes no bonding to the transparent plate. The separating layer, or transparent film, does not adhere to the transparent plate and is deformed elastically during the separation process causing peeling of the film from the hardened layer. If the transparent film is of high-elasticity material, a shearing effect can be of help during the separation process. <CIT> therefore teaches that the combination of peeling and shearing effects facilitates the separation and limits the path of separation.

International patent application <CIT> discloses an apparatus for making an object using a stereolithographic method. The apparatus comprises a positioner which is configured for moving a platform on which the object is made and, alternatively or additionally, the positioner may be arranged to move a flexible element and a surface towards the platform.

Patent application <CIT> discloses an additive manufacturing system for additively manufacturing an object layer by layer, comprising a tank filled with a volume of a polymerizable material, a building platform on which layers made from the polymerizable material are formed, a curing device configured for at least partially hardening the layers of the object to be manufactured, a transparent plate located between the building platform and the curing device, and a flexible separation film mechanically connected by ends to a frame and at least partially located between the transparent plate and the building platform, the additive manufacturing system being configured so that the transparent plate, the frame and the building platform are movable relative to one another between a first relative position corresponding to building positions of a layer, in which the transparent plate is applied against the flexible separation film which is in a tense state, and a second relative position corresponding to layering positions of a layer, in which the transparent plate is moved relative to the frame and is remote to the flexible separation film which is at least partially in a loose state.

The disclosure is directed to a manufacturing system configured to carry out a method for additively manufacturing an ophthalmic device, and to the method for additively manufacturing such an ophthalmic device including curing and layering steps thanks to a transparent plate and a flexible separation film.

The disclosure accordingly provides an additive manufacturing system for additively manufacturing an ophthalmic device layer by layer, comprising a tank filled with a volume of a polymerizable material, a building platform on which layers made from the polymerizable material are formed, a curing device configured for at least partially hardening the layers of the ophthalmic device to be manufactured, a transparent plate located between the building platform and the curing device, and a flexible separation film mechanically connected by ends to a frame and at least partially located between the transparent plate and the building platform, the additive manufacturing system being configured so that the transparent plate, the frame and the building platform are movable relative to one another and to the tank between a first relative position corresponding to building positions of a layer, in which the transparent plate is applied against the flexible separation film which is in a tense state, and a second relative position corresponding to layering positions of a layer, in which the transparent plate is moved relative to the frame and is remote to the flexible separation film which is at least partially in a loose state.

In the manufacturing system according to the disclosure, thanks to the relative movement between the transparent plate, the frame to which is mechanically connected the flexible separation film, the building platform and the tank, these parts can be made either in a first relative position corresponding to building positions of a layer, in which the transparent plate is applied against the flexible separation film which is in a tense state, or in a second relative position corresponding to layering positions of a layer, in which the transparent plate is moved relative to the frame and is remote to the flexible separation film.

When the transparent plate, the flexible separation film and the building platform are in building positions, the layer is cured thanks to the curing device.

When the transparent plate, the flexible separation film and the building platform are in layering positions, the flexible separation film is detached from the layer previously cured.

In this respect, at least the transparent plate and the flexible separation film are moved remote to each other.

Before peeling, the flexible separation film is at least partially loose.

During peeling, the flexible separation film is tensed, but not stretched. When the flexible separation film is detached from the layer previously cured, the flexible separation film is fully loose.

The force applied to the flexible separation film is in relation to the tearing effect between the flexible film and the polymerised predetermined material.

In other words, thanks to the manufacturing system according to the disclosure, the flexible separation film may have a state in which it is fully loose, at least partially loose and at least partially tensed, and fully tensed.

The flexible separation film is never or almost never in a stretch state. At worst, the flexible separation film could be stretched for a very short time, for instance no more than few seconds, and the flexible separation film could be very shortly elongated, for instance in a range lower than <NUM> %.

Thus, in the present disclosure, the flexible separation film is tensed when it is very shortly elongated according the Hooke's law. The forces are thus regularly distributed along the flexible separation film.

The flexible separation film can also be stretched when it is also very shortly elongated preferably in the elastically zone. If any, the forces are rather localized on the flexible separation film.

To be noted that the loose state of the flexible separation film allows reducing the solicitations of the flexible separation film during the manufacturing of the ophthalmic device such that the flexible separation film has a longer lifespan and/or keeps its usual properties.

For instance, thanks to the manufacturing system according to the disclosure, there is no need to inflate and deflate, successively and with a dedicated fluid, the flexible separation film. The flexible separation film is thus less solicited.

Advantageous and convenient features of the manufacturing system are described below.

The additive manufacturing system comprises a moving unit configured to move one relative to the others of the building platform, the transparent plate and the frame to which is mechanically connected by ends of the flexible separation film.

The moving unit acts on the building platform, and on the transparent plate, and on the frame bearing partially the flexible separation film, dependently or independently.

The moving unit is configured: to raise up or down the building platform towards or remote to a bottom of the tank; and raise up or down the transparent plate towards or remote to the bottom of the tank and thus towards or remote to the building platform; and raise up or down the frame to which the flexible separation film is mechanically connected, towards or remote to the bottom of the tank in order to locate at least a part of the flexible separation film in a position relative to both building platform and transparent plate; and raise up or down the tank relative to at least one of the building platform, transparent plate and frame to which the flexible separation film is mechanically connected.

In building positions, the transparent plate is located close to the building platform and acts on a middle portion of the flexible separation film so that the middle portion of the flexible separation film is tensed, but not stretched, and a predetermined thickness of the polymerizable material remains between the middle portion of the flexible separation film and an uppermost layer on the building platform.

The flexible separation film comprises other portions which are interposed between the middle portion and the ends of flexible separation film, which are remote to the layer and located between the frame to which the flexible separation film is mechanically connected by the ends and an outline of the layer.

The other portions of the flexible separation films are at least partially tensed thanks to the action of the transparent plate which is located at a distance from the frame.

The other portions of the flexible separation film may have a substantially L-shape, having a first arm extending from the middle portion and along the transparent plate and a second arm extending from the first arm to the frame.

To be noted that the L-shape of the other portions of the flexible separation film does not mean that the first arm and the second arm are necessarily at a right angle one to each other. For instance, the first arm and the second arm are inclined one to each other by an angle comprised between around <NUM>° and about <NUM>°.

In at least layering positions, the transparent plate is moved remote to the building platform and the flexible separation film and is located close to the frame to which the flexible separation film is mechanically connected by the ends, and a temporary space is formed between the transparent plate and the flexible separation film.

The flexible separation film comprises a middle portion and other portions extending from the middle portion to the ends of the flexible separation film, the middle portion being at least partially tensed due to an adhesive contact with a cured uppermost layer, and the other portions being loose, so that the other portions are at least partially free of movement between the tensed portion and the respective ends.

The layering positions includes positions in which the flexible separation film is fully peeled away from and located remote to a cured uppermost layer on the building platform, and is fully loose and free of movement between the ends.

The disclosure further provides a method for additively manufacturing an ophthalmic device layer by layer, the manufacturing method comprising the steps of:.

The method comprises the steps of moving relative to one another and to the tank, the building platform, the transparent plate and the frame to which is mechanically connected by ends of the flexible separation film; and in particular: raising up or down the building platform towards or remote to a bottom of the tank; and raising up or down the transparent plate towards or remote to the bottom of the tank and thus towards or remote to the building platform; and raising up or down the frame to which the flexible separation film is mechanically connected, towards or remote to the bottom of the tank in order to locate at least a part of the flexible separation film in a position relative to both building platform and transparent plate; and raising up or down the tank relative to at least one of the building platform, transparent plate and frame to which the flexible separation film is mechanically connected.

In building positions, the transparent plate is located close to the building platform and acts on a middle portion of the flexible separation film so that the middle portion of the flexible separation film is tensed, but not stretched, and a predetermined thickness of the polymerizable material remains between the middle portion of the flexible separation film and an uppermost layer on the building platform, and/or the flexible separation film comprises other portions which are interposed between the middle portion and the ends of flexible separation film, which are remote to the layer and located between the frame to which the flexible separation film is mechanically connected by the ends and an outline of the layer, and/or the other portions of the flexible separation films are at least partially tensed thanks to the action of the transparent plate which is located at a distance from the frame.

In at least layering positions, the transparent plate is moved remote to the building platform and the flexible separation film and is located close to the frame to which the flexible separation film is mechanically connected by the ends, and a temporary space is formed between the transparent plate and the flexible separation film, and the flexible separation film comprises a middle portion and other portions extending from the middle portion to the ends of the flexible separation film, the middle portion being tensed due to an adhesive contact with a cured uppermost layer, and the other portions being loose, so that the other portions are at least partially free of movement between the tensed portion and the respective ends; and the layering positions includes positions in which the flexible separation film is fully peeled away from and located remote to a cured uppermost layer on the building platform, and is fully loose and free of movement between the ends.

The description of the disclosure now continues with a detailed description of advantageous embodiments given hereinafter by way of nonlimiting example and with reference to the appended drawings.

<FIG> illustrates schematically a manufacturing system <NUM> configured to carry out a method for additively manufacturing ophthalmic devices <NUM>.

The manufacturing system <NUM> comprises a tank <NUM> filled with a volume of a predetermined material <NUM> suitable for manufacturing ophthalmic devices <NUM>, such as a liquid resin for making eyeglasses.

The manufacturing system <NUM> is an additive system configured for manufacturing the ophthalmic devices <NUM> layer by layer, each layer <NUM> being formed by a volume of the predetermined material <NUM> at least partially polymerized and hardened.

In this respect, the manufacturing system <NUM> comprises an unit <NUM> configured for projecting and polymerizing at least one image on a surface <NUM> of the volume of the predetermined material <NUM> in the tank <NUM>, also called additive unit.

The additive unit <NUM> may comprise a processing apparatus <NUM> having for instance a digital lighting processor which is configured for processing a single image, or pattern, and/or a plurality of images, or patterns.

The additive unit <NUM> may further comprise a projecting and polymerizing apparatus <NUM> configured for providing a curing energy, and having for instance a projector and a radiation source, or energy source, or other well-known sources for projecting the single image in a single direction toward the material <NUM> for each layer <NUM>, and/or a plurality of images projected simultaneously of successively, and then polymerizing and hardening the material <NUM>.

In variant, the digital lighting processor and polymerizing apparatus are replaced by a laser source and a scanning device which are configured for scanning with the laser source the surface <NUM> of the material <NUM>.

In <FIG>, the additive unit <NUM> is located on an upper side of the tank <NUM>, and faces an upper opening <NUM> of the tank <NUM> which is opposite to a bottom <NUM> of the tank <NUM>. Such arrangement allows carrying out a so-called top-down process, as explained below.

In another arrangement, the additive unit can be located on a lower side of the tank, and faces a supplemental opening formed on the bottom of the tank. Such another arrangement allows carrying out a so-called bottom-up process, as also explained below.

The manufacturing system <NUM> further comprises a building platform <NUM> at least partially immersed in the tank <NUM>, a transparent plate <NUM> and a flexible separation film <NUM> represented in <FIG> as being laid on the transparent plate <NUM> and being in contact therewith.

The flexible separation film <NUM> faces the building platform <NUM> and the transparent plate <NUM> faces the additive unit <NUM>.

The flexible separation film <NUM> is mechanically connected by ends <NUM> to a frame <NUM> of the manufacturing system <NUM>.

The transparent plate can be made from glass or plastic, while the flexible separation film can be made for instance from polytetrafluoroethylene (PTFE). In variants, the flexible separation film can be made for instance from Teflon AF such as for instance AF <NUM> or AF <NUM>, or perfluoroelastomers (PFE), polypropylene (PP), polyethylene terephthalate (PET), perfluoroalkoxy (PFA), or also from silicone, etc..

The additive unit <NUM> is thus configured for projecting at least one image, or pattern, on the surface <NUM> of the volume of the predetermined material <NUM> in the tank <NUM> for forming each layer <NUM> of the ophthalmic device <NUM> on the building platform <NUM>, through the transparent plate <NUM> and flexible separation film <NUM>, so that each layer <NUM> which is formed and at least partially hardened is sandwiched between the building platform <NUM> and the flexible separation film <NUM>.

In particular, the additive unit <NUM> is able to transfer to the surface of the volume of the predetermined material, in an image or a pattern, a quantity of energy suitable to trigger polymerization of the predetermined material.

The manufacturing system <NUM> further comprises a moving unit <NUM> configured to move the building platform <NUM>, the transparent plate <NUM> and the frame <NUM> one relative to the others and to the tank.

The building platform <NUM>, the transparent plate <NUM> and the flexible separation film <NUM> are each mounted, directly or indirectly, on a rigid body <NUM>, and may be mounted movable relative to the rigid body <NUM>.

The moving unit <NUM> may act on the building platform <NUM>, or on the transparent plate <NUM>, or on the frame <NUM> bearing partially the flexible separation film <NUM>, or on both of them. The moving unit <NUM> may act on the building platform <NUM>, the transparent plate <NUM> and the flexible separation film <NUM> dependently or independently.

In particular, and as better explained below, the moving unit <NUM> may be configured to:.

In an alternative embodiment, the moving unit <NUM> may be configured to raise up or down the tank <NUM> relative to at least one of the building platform <NUM>, transparent plate <NUM> and frame <NUM> to which the flexible separation film <NUM> is mechanically connected.

<FIG> is a block diagram showing the main steps of the method for additively manufacturing ophthalmic devices <NUM> carried out thanks to the manufacturing system <NUM> as described above.

The method comprises successive steps <NUM> of additively manufacturing the plurality of layers <NUM> of the predetermined material <NUM>, layer by layer.

The main steps of the method comprises iteratively steps of layering <NUM> and steps of curing <NUM> in order to from, layer by layer, the ophthalmic devices <NUM>.

The steps of layering <NUM> are carried out for locating the parts of the manufacturing system, including at least the building platform <NUM>, the transparent plate <NUM> and the flexible separation film <NUM>, in a building position in which only a predetermined thickness of the predetermined material <NUM> is provided between the flexible separation film <NUM> and the building platform <NUM> or a layer already formed thereon. The predetermined thickness of the predetermined material <NUM> corresponds to the thickness of the layer, when cured, to be formed.

The steps of layering <NUM> comprise the step <NUM> of moving the building platform <NUM> in a predetermined position, and the step <NUM> of moving the frame <NUM> to which the flexible separation film <NUM> is mechanically fastened, relative to the building platform <NUM>, and the step <NUM> of moving the transparent plate <NUM> relative to the building platform <NUM> and relative to the frame <NUM> to which the flexible separation film <NUM> is mechanically fastened.

The curing steps <NUM> comprise the steps of projecting and polymerizing at least one image on the surface <NUM> of the volume of the predetermined material <NUM> in the tank <NUM>, through the transparent plate <NUM> and the flexible separation film <NUM> laying on the transparent plate <NUM> and being in contact therewith.

The curing steps <NUM> encompass the projection of a single image in a single direction toward the material <NUM>, for instance thanks to the projecting apparatus <NUM>, or the projection of a plurality of images projected simultaneously of successively. Such a process is usually called DLP process.

In variant, the step of projecting an image encompasses the scanning by a laser source of the surface of the material. Such a process is usually called SLA process.

Each layer <NUM> of the ophthalmic device <NUM> is formed, or layered, and at least partially hardened by curing, on the building platform <NUM> or on a previous layer on this platform, in a location wherein the layer <NUM> is sandwiched between the building platform <NUM> or the previous layer and the flexible separation film <NUM>.

When the layer <NUM> is cured, the flexible separation film <NUM> is in contact with the hardened or partially hardened layer <NUM> so that the flexible separation film <NUM> at least partially adheres to the hardened or partially hardened layer <NUM>.

Therefore, following the curing step, when a further layering step is carried, there is a need to peel the flexible separation film <NUM> from the hardened or partially hardened layer <NUM> without damaging the latter.

<FIG> show in detail certain steps of the method shown on Figure and carried out by the manufacturing system visible on <FIG>.

In particular, the curing step <NUM> illustrated in <FIG> is followed by the layering step <NUM> in <FIG>, which <FIG> can be equated also to a further curing step <NUM>.

In <FIG>, the building platform <NUM> is immersed in the predetermined material <NUM> at a building position in the tank <NUM>.

A plurality of layers <NUM> at least partially hardened are already formed on the building platform <NUM>.

The transparent plate <NUM> is here located close to the building platform <NUM> and acts on a portion <NUM> of the flexible separation film <NUM> so that the portion <NUM> of the flexible separation film <NUM> is tensed, but not stretched, and a predetermined thickness <NUM> of the predetermined material <NUM> remains between the portion <NUM> of the flexible separation film <NUM> and the uppermost layer <NUM> on the building platform <NUM>.

In this configuration of the manufacturing system, which can be equated to a curing configuration, the curing device (not represented on <FIG>) can operate for at least partially hardening the volume of predetermined material <NUM> in the predetermined thickness <NUM> between the portion <NUM> of the flexible separation film <NUM> and the uppermost layer <NUM> on the building platform <NUM> in order to form a novel uppermost layer <NUM> (visible in <FIG>).

In <FIG>, the building platform <NUM>, the transparent plate <NUM> and the flexible separation film <NUM> are in first relative positions corresponding to building positions of a layer <NUM>.

The transparent plate <NUM> is here wider than the building platform <NUM> and the layer <NUM> to be formed so that portions <NUM> of the flexible separation film <NUM>, interposed between the tensed portion <NUM> and the ends <NUM> of flexible separation film <NUM>, are not in contact with the layers <NUM>.

The portions <NUM> of the flexible separation film <NUM> are here located between the frame <NUM> to which the flexible separation film <NUM> is mechanically connected by the ends <NUM> and an outline of the layers <NUM>.

The portions <NUM> of the flexible separation film <NUM> are at least partially tensed thanks to the action of the transparent plate <NUM> which is here located at a distance, said building distance, of the frame <NUM>.

In the curing configuration of the manufacturing system, the portions <NUM> of the flexible separation film <NUM> may have an L-shaped, having a first arm extending from the portion <NUM> and along the transparent plate <NUM> and a second arm extending from the first arm to the frame <NUM>.

To be noted that the transparent plate <NUM> comprises vents <NUM> which are here formed at the location of the portions <NUM> of the flexible separation film <NUM>.

In an alternative embodiment, the transparent plate <NUM> can be devoid of such vent because of no-sealing contact between the flexible separation film <NUM> and the transparent plate <NUM>.

In <FIG>, the transparent plate <NUM> has been moved remote to the building platform <NUM> and the flexible separation film <NUM>.

The transparent plate <NUM> has been raised up and is located close to the frame <NUM> to which the flexible separation film <NUM> is mechanically connected by the ends <NUM>.

The transparent plate <NUM> is thus no longer in contact with the flexible separation film <NUM> and a temporarily space <NUM> is formed there-between.

The temporarily space <NUM> can be filled of a fluid, such as for instance air, thanks to the vents <NUM>.

The portion <NUM> of the flexible separation film <NUM> remains tensed due to the adhesive contact with the cured uppermost layer <NUM>, while the portions <NUM> of the flexible separation film <NUM> are loose, or in a loose state.

Said otherwise, the portions <NUM> are at least partially free of movement between the tensed portion <NUM> and the respective ends <NUM>.

In <FIG>, the building platform <NUM> has been moved remote to the transparent <NUM>.

The building platform <NUM> has been raised down towards the bottom of the tank <NUM> and remotely from the frame <NUM> to which the flexible separation film <NUM> is mechanically connected by the ends <NUM>.

The temporarily space <NUM> defined between the transparent plate <NUM> and the flexible separation film <NUM> has been expanded.

The portion <NUM> of the flexible separation film <NUM> remains tensed due to the adhesive contact with the cured uppermost layer <NUM> yet, while the portions <NUM> of the flexible separation film <NUM> are no longer loose.

The portions <NUM> are now tensed, not stretched, between the tensed portion <NUM> and the respective ends <NUM>.

In <FIG>, the building platform <NUM> has been further moved remote to the transparent <NUM> and raised down towards the bottom of the tank <NUM>, remotely from the frame <NUM> to which the flexible separation film <NUM> is mechanically connected by the ends <NUM>.

The temporarily space <NUM> defined between the transparent plate <NUM> and the flexible separation film <NUM> has been further expanded.

The flexible separation film <NUM> begins to peel away from the cured uppermost layer <NUM>.

The portion <NUM> which is tensed and in contact with the cured uppermost layer <NUM> decreases, while the portions <NUM> extending between the portion <NUM> and the ends <NUM> increases and are tensed.

The flexible separation film <NUM> continues to peel away from the cured uppermost layer <NUM>.

The portion <NUM> which is tensed and in contact with the cured uppermost layer <NUM> rather disappeared, while the portions <NUM> extending between the portion <NUM> and the ends <NUM> further increases and are tensed.

In <FIG>, the flexible separation film <NUM> is fully peeled away from the cured uppermost layer <NUM>.

The flexible separation film <NUM> has no longer portion <NUM> which is tensed and in contact with the cured uppermost layer <NUM>.

The portions <NUM> thus form a single portion extending between the ends <NUM>, and which is fully loose and free of movement. This single portion <NUM> is located remote to the uppermost layer <NUM> on the building platform <NUM>.

It is to be noted that between <FIG> and <FIG>, the transparent plate and next the building platform have been moved. In variant, they can be successively and iteratively moved, the building platform can be moved before transparent plate, or the frame, directly via the tank, can be additionally or alternatively moved rather than the building platform.

In <FIG>, both transparent plate <NUM> and building platform <NUM> are moved towards each other and relative to the frame <NUM>.

The transparent plate <NUM> is thus raised down towards the building platform <NUM> and the latter is thus raised up towards the transparent plate <NUM>, opposite to the bottom of the tank <NUM>.

The building platform <NUM> is moved until it reaches a building position in the tank <NUM>, which can be the same or different for the building position shown in <FIG>.

The transparent plate <NUM> has an abutting face <NUM> which pushes, directly and/or with the aid of the fluid in the temporarily space <NUM> which decreases, and tenses progressively the flexible separation film <NUM> until a part of the latter, equated to the portion <NUM> as defined below, is located in front of the uppermost layer <NUM>, with a predetermined thickness <NUM> of the predetermined material <NUM> which remains between the portion <NUM> of the flexible separation film <NUM> and the uppermost layer <NUM> on the building platform <NUM>, and the portions <NUM> are progressively tensed and extend between the portion <NUM> and the frame <NUM>.

In <FIG>, the building platform <NUM>, the transparent plate <NUM> and the flexible separation film <NUM> are in second relative positions corresponding to layering positions for a novel layer <NUM>.

In <FIG>, like in <FIG>, the transparent plate <NUM> is located close to the building platform <NUM> and acts on the portion <NUM> of the flexible separation film <NUM> so that the portion <NUM> of the flexible separation film <NUM> is tensed, or in a tense state, but not stretched, and the predetermined thickness <NUM> of the predetermined material <NUM> remains between the portion <NUM> of the flexible separation film <NUM> and the uppermost layer <NUM> on the building platform <NUM>.

In this curing configuration, the curing device (not represented on <FIG>) can operate for at least partially hardening the volume of predetermined material <NUM> in the predetermined thickness <NUM> between the portion <NUM> of the flexible separation film <NUM> and the uppermost layer <NUM> on the building platform <NUM> in order to form another novel uppermost layer <NUM>.

In other words, <FIG> illustrate the passage of the manufacturing system from the curing configuration of a layer, to a layering configuration and then to the curing configuration of a successive layer.

According to the above description of the manufacturing system and method, the flexible separation film <NUM> may have a state in which it is fully loose, at least partially loose and at least partially tensed, and fully tensed. However, the flexible separation film <NUM> is never stretched.

In addition, the manufacturing system <NUM> requires leaving a sufficient space between the transparent plate <NUM> and the building platform <NUM> in order to allow the flexible separation film <NUM> to be loose.

In this respect, it is described above that the portions <NUM> of the flexible separation film <NUM> may have an L-shaped in the curing configuration.

The first arm extending from the portion <NUM> and along the transparent plate <NUM> corresponds to a first distance, for instance called horizontal distance, between an edge of the transparent plate <NUM> and the outline of the uppermost layer <NUM>.

The second arm extending from the first arm to the frame <NUM> corresponds to a second distance, for instance called vertical distance, between the frame <NUM> and the edge of the transparent plate <NUM>.

These first arm, second arm and first and second distances are visible on <FIG>.

In <FIG>, the first distance remains constant while the second distance increases, from a peeling start position of the flexible separation film <NUM> shown on <FIG> to a peeling end position of the flexible separation film <NUM> shown on <FIG>.

As shown in <FIG>, the flexible separation film <NUM> can thus be peeled away from the uppermost layer <NUM> with a relatively high peeling angle.

Such a relatively high peeling angle may lead to less stress for both the layer <NUM> and the flexible separation film <NUM>.

Leading less stress is better for both the optical quality of the layer <NUM> and the lifespan of the flexible separation film <NUM>.

In addition, such a relatively high peeling angle may allow reducing the time of the layering steps, for instance by controlling the speed of the movements of at least one of the building platform <NUM>, transparent plate <NUM> and flexible separation film <NUM>.

In this respect, it can be noted that when at least a part of the flexible separation film <NUM> is loose, the velocity of the movement can be higher than when the flexible separation film <NUM> is tensed.

In other words, from <FIG>, the velocity of the movement of the transparent plate <NUM> and/or building platform <NUM> can be relatively high, whereas during the peeling as such, shown on <FIG>, the velocity of the movement of the transparent plate <NUM> and/or building platform <NUM> should be decreased compared to <FIG>. In addition, from <FIG>, the velocity of the movement of the transparent plate <NUM> and/or building platform <NUM> in order to make the system in the curing configuration by locating the building platform <NUM> in its building position, approaching the transparent plate <NUM> and tensing progressively the flexible separation film <NUM>, should be also decreased compared to <FIG> and can be rather similar, or lower, or higher, compared to the velocity of the movement during peeling and shown on <FIG>.

Other variants which are not illustrated are described below.

The transparent plate may have different shape, including squared, rectangular or others shapes, including a building zone and an edge zone surrounding the building zone.

The transparent plate is transparent to UV light. The transparent plate can be made from glass and/or quartz and/or plastic and/or composite of materials.

The transparent plate can have a hydrophobic treatment.

The building zone may have may have a length equal to around <NUM> or higher than <NUM>, and a width equal to around <NUM>, and the edge zone may have, on each longitudinal side of the building zone, a width equal to around <NUM> or lower than <NUM> and, on each transversal side of the building zone, a length equal or higher than the width on each longitudinal side of the building zone, especially if vents are formed on the transparent plate.

The manufacturing system may further comprises a fluid supply unit configured to supply and suck a fluid between the flexible separation film and the transparent plate.

Claim 1:
An additive manufacturing system for additively manufacturing an ophthalmic device layer by layer, comprising a tank (<NUM>) filled with a volume of a polymerizable material (<NUM>), a building platform (<NUM>) on which layers (<NUM>) made from the polymerizable material are formed, a curing device (<NUM>) configured for at least partially hardening the layers of the ophthalmic device to be manufactured, a transparent plate (<NUM>) located between the building platform (<NUM>) and the curing device (<NUM>), and a flexible separation film (<NUM>) mechanically connected by ends (<NUM>) to a frame (<NUM>) and at least partially located between the transparent plate (<NUM>) and the building platform (<NUM>), the additive manufacturing system (<NUM>) being configured so that the transparent plate, the frame and the building platform are movable relative to one another and to the tank (<NUM>) between a first relative position corresponding to building positions of a layer, in which the transparent plate is applied against the flexible separation film which is in a tense state, and a second relative position corresponding to layering positions of a layer, in which the transparent plate is moved relative to the frame and is remote to the flexible separation film which is at least partially in a loose state.