TITLE

Three-dimensional optical structure, method for manufacturing a three-dimensional optical structure

BACKGROUND

The present invention relates to a three-dimensional optical structure and to a method for manufacturing a three-dimensional optical structure.

Printed three-dimensional optical structures such as ophthalmic lenses are known from the prior art. A major advantage of printed three-dimensional optical structures is their variability and versatility, especially with regard to individual customizability and the possibilities of special uses. Not only is it easy to customize optical functions of the optical structure during manufacturing, but the optical structure can also be specially adapted for the integration of functional components. For example, it is conceivable that the three-dimensional optical structure is worn as the lens of a pair of glasses through which information is displayed to the wearer, for example as augmented reality glasses.

For this purpose, it is typically necessary that the three-dimensional optical structure comprises a functional structure that is capable of displaying the information to be superimposed. To protect the functional structure and to improve the optical quality, this functional structure can be enclosed in the optical structure as an enclosed structure.

One technical difficulty here is the transport of information through the optical structure. For highest optical quality, a low loss of information transport due to scattering, unwanted reflections or unwanted leakage from the optical structure is essential.

SUMMARY

Hence, it is a purpose of the present invention to provide a three-dimensional optical structure, in particular a lens, which does not show the described disadvantages of the prior art, but allows an excellent transport of information in the form of light through the optical structure for use in an enclosed structure. According to the present invention, this object is achieved by a three-dimensional optical structure, in particular a lens, wherein the optical structure comprises a first half, a printed second half, and an enclosed structure arranged between the first half and the second half, wherein an air gap is arranged between the enclosed structure and the first half and/or the second half.

The air gap advantageously allows total reflection in the optical structure to be used to transport information in the form of light. The transport mechanism is extremely efficient and offers very low losses.

Preferably, the first half is printed or casted.

An optical structure in the sense of the present invention comprises lenses. Lenses may comprise ophthalmic lenses. Ophthalmic lenses comprise concave, convex, biconcave, biconvex and meniscus lenses. Ophthalmic lenses in the sense of the present invention also comprise multifocal lenses as well as gradient-index lenses. Ophthalmic lenses comprise in particular spectacle lenses or other lenses that are not inserted into the eye.

In the sense of the present invention, printing of an optical structure comprises building up the structure from layers of printing ink. These are obtained through a targeted placement of droplets of printing ink at least partially side by side. The droplets of printing ink are ejected from the nozzles of a print head, typically towards a substrate. Droplets of layers constituting a second and following layers are at least partly ejected towards a previously deposited layer, such that the three-dimensional structure is built up layer by layer.

The printing ink preferably comprises a translucent or transparent component. Preferably, the printing ink comprises at least one photo-polymerizable component. The at least one photo- polymerizable component is preferably a monomer that polymerizes upon exposure to radiation, e.g. ultra-violet (UV) light. The deposited droplets are preferably pin cured, i.e. partially cured, after deposition. Preferably, the viscosity of at least one component of the printing ink is increased. Pin curing is preferably carried out after deposition of the respective droplet or after deposition of an entire or only part of a layer. Alternatively, pin curing is carried out at certain intervals, e.g. after printing of every second layer.

According to a preferred embodiment of the present invention, a spacer is arranged between the first half and the enclosed structure and/or between the second half and the enclosed structure for spacing the enclosed structure from the first half and/or the second half and thus for providing the air gap, the spacer preferably being printed. This advantageously comprises a stable and well-defined air gap. It is conceivable that the spacer is arranged parallel to an outer edge of the first half and/or the second half, at least partially circumferentially.

According to another preferred embodiment of the present invention, the enclosed structure is bonded to the spacer. This advantageously enables the tightly encapsulated strut cure to be securely and stationarily anchored in the optical structure.

According to another preferred embodiment of the present invention, the air gap is arranged between the first half and the enclosed structure and a further air gap is arranged between the second half and the enclosed structure, wherein a further spacer is preferably arranged between the second half and the enclosed structure for spacing the second half from the enclosed structure and thus providing the further air gap, wherein the further spacer is particularly preferably printed. This advantageously provides a further possibility for effective information transport by means of total reflection. The further spacer ensures a stable further air gap with well-defined dimensions. Preferably, the further spacer is bonded to the enclosed structure.

According to another preferred embodiment of the present invention, between the first half and the second half there is arranged an enclosure at least partially enclosing the enclosed structure and the air gap, the enclosure being arranged along an outer edge of the optical structure, the enclosure preferably being printed. The enclosure advantageously enables a stable hold for mounting the optical structure as well as effective protection against mechanical damage caused by lateral forces and helps to prevent moister entering the enclosed structure.

According to another preferred embodiment of the present invention, the enclosed structure is a light guiding structure. This advantageously opens up the technical possibility of using the optical structure to superimpose information, for example for applications in the field of augmented reality.

According to another preferred embodiment of the present invention, the first half and/or the second half comprises an opening to the air gap. The aperture advantageously allows light to be guided or coupled into the optical structure. It is conceivable that the opening comprises an entrance opening of a light guiding element. It is conceivable that the opening comprises an optical component to couple-in light in a light guiding element. A further object for the solution of the problem presented above is a method for manufacturing a three-dimensional optical structure, preferably a lens, in particular an optical structure according to the invention, wherein

- in a first step, a first half is provided, preferably printed or casted,

- in a second step, a spacer is printed on a surface of the first half,

- in a third step, an enclosed structure is arranged on the spacer such that the enclosed structure is spaced from the first half by an air gap,

- in a fourth step, a second half is printed so that the enclosed structure is arranged between the first half and the second half.

The method according to the invention advantageously allows the production of a highly individualized and functionalized optical structure, which offers the possibility of efficient and extremely low-loss information transport by total reflection of light within the optical structure.

According to another preferred embodiment of the present invention, a holder is provided, preferably printed, wherein the first half is arranged on the holder between the first step and the second step. This advantageously ensures that precise assembly of the optical structure is possible. Preferably, the first half is rotated before being placed in the holder so that the side of the first half that comprises the last printed layers faces the holder.

According to another preferred embodiment of the present invention, the holder is provided, preferably printed, with a recess at least partially circumferential on an inner side, wherein the first half is printed with a lug provided for engagement in the recess. This further improves the precision of the manufacturing process and thus the optical quality of the optical structure. This prevents the individual components, especially the first half, from slipping during assembly of the optical structure.

According to another preferred embodiment of the present invention, the spacer remains at least partially uncured prior to the third step, wherein the spacer is fully cured after the third step. This is an advantageous way of bonding the enclosed structure to the spacer without having to use an additional adhesive.

According to another preferred embodiment of the present invention, after the third step a further spacer is arranged, preferably printed, on the enclosed structure for spacing the second half from the enclosed structure and thus providing a further air gap. This advantageously opens up a further possibility of total reflection, whereby the dimensions of the further air gap can be very precisely adjusted by the further spacer. Preferably, it is provided that the further spacer is arranged at least partially parallel to the outer edge of the second half circumferentially.

According to another preferred embodiment of the present invention, between the first step and the third step, preferably between the first step and the second step, an enclosure arranged along the outer edge of the first half is arranged, preferably printed, wherein the height of the enclosure corresponds at least to the height of the enclosed structure plus the air gap, preferably exactly the height of the enclosed structure plus the air gap, or the height of the enclosure corresponds at least to the height of the enclosed structure plus the air gap and the further air gap, preferably exactly to the height of the enclosed structure plus the air gap and the further air gap. This advantageously further enhances the stability during the assembly of the optical structure, which directly leads to an improvement in the optical quality of the optical structure.

According to another preferred embodiment of the present invention, between the third step and the fourth step a gap between the enclosed structure and the enclosure is filled with a printing ink, wherein the printing ink is not cured or is only partially cured. This advantageously further increases the stability of the optical structure. Alternatively, the gap remains unfilled so that the gap is a lateral air gap.

According to another preferred embodiment of the present invention, the enclosure is arranged or printed so as to force the enclosed structure into an intended position in the third step, the enclosure preferably being arranged or printed so such that its outer edge terminates with the outer edge of the first half, the second half preferably being printed such that its outer edge terminates with the outer edge of the enclosure. In particular, the enclosed structure can thus be arranged extremely precisely by supporting it on the side wall of the enclosure. By supporting the encapsulated structure is arranged extremely precisely. Furthermore, the flush closure avoids edges, which gives the optical structure a much more pleasing and high-quality shape and makes it less sensitive to mechanical impact, e.g. due to lateral bumping.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 (a) to (g) schematically illustrate a method according to an exemplary embodiment of the present invention and a three-dimensional optical structure according to an exemplary embodiment of the present invention. Figures 2 (a) to (c) schematically illustrate details of three-dimensional optical structures according to exemplary embodiments of the present invention.

Figure 3 schematically illustrates details of three-dimensional optical structures according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

The present invention will be described with respect to particular embodiments and with target to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and for illustrative purposes may not be drawn to scale.

Where an indefinite or definite article is used when referring to a singular noun, e.g. “a”, “an”, “the”, this includes a plural of that noun unless something else is specifically stated.

Furthermore, the terms first, second, further and the like in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, except for the method steps. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

In Figure 1 (a) to (g), a method according to an exemplary embodiment of the present invention and a three-dimensional optical structure 100 according to an exemplary embodiment of the present invention are schematically illustrated. Figure 1(a) shows a holder 8 as used to support the optical structure 100 during its manufacture. Clearly visible is the recess 8' which holds the first half 1 (see Figure 1(b)) in position. The holder 8 is preferably printed.

Figure 1(b) shows the first half 1. The first half 1 is printed on a substrate (not shown) in a first step. Printing of the first half 1 , as well as printing of the holder 8, the second half 2 (Figure 1 (g)), the enclosure 6 (Figure 1(d)) and the spacer 5 (Figure 1(e)) comprises building up the component from layers of printing ink. These are obtained through a targeted placement of droplets of printing ink at least partially side by side. The droplets of printing ink are ejected from the nozzles of a print head, typically towards a substrate. Droplets of layers constituting a second and following layers are at least partly ejected towards a previously deposited layer, such that the structure is built up layer by layer.

The printing ink comprises a translucent or transparent component and at least one photo- polymerizable component. The at least one photo-polymerizable component is a monomer that polymerizes upon exposure to radiation, e.g. ultra-violet (UV) light. The deposited droplets are preferably pin cured, i.e. partially cured, after deposition. Preferably, the viscosity of at least one component of the printing ink is increased. Pin curing is preferably carried out after deposition of the respective droplet or after deposition of an entire or only part of a layer. Alternatively, pin curing is carried out at certain intervals, e.g. after printing of every second layer. The first half 1, as well as the holder 8, the second half 2 and the enclosure 6 are cured after printing.

To ensure a secure hold of the first half 1 in the holder 8, the first half is provided with a lug T. After the first step, the first half 1 is rotated for precise assembly of the optical structure 100 and inserted into the holder 8 (Figure 1(c)).

An enclosure 6 is then printed onto the inserted first half 1 (Figure 1(d)). The enclosure 6 is arranged along the outer edge of the first half 1. In a second step, a spacer 5 is printed onto the first half 1 along the inside of the enclosure 6 (Figure 1(e)). At least the last layers of printing ink of the spacer 5 are not cured at first.

Subsequently, in a third step, an enclosed structure 3, which is a light guide structure, is placed on the spacer 5 (Figure 1(f)). The spacer 5 is then cured, which bonds it to the enclosed structure 3. The spacer 5 spaces the enclosed structure 3 from the first half 1, creating an air gap (see Figure 2). The air gap allows total reflection of light propagating along the air gap through the optical structure 100.

In a fourth step, the second half 2 is then printed onto the enclosed structure 3 (Figure 1(g)). After the second half 2 has cured, the optical structure 100 can be removed from the holder Figures 2 (a) to (c) schematically illustrate details of three-dimensional optical structures 100 according to exemplary embodiments of the present invention.

Figure 2(a) shows a detail of a lateral section through the optical structure 100, showing the holder 8 with the recess 8' and the first half 1, which is securely arranged with the lug 1' in the recess 8'. Concluding with the outer edge of the first half 1 is printed the enclosure 6, which protects the enclosed structure 3 laterally from damage. The spacer 5, which distances the encapsulated structure 3 from the first half 1 and thus creates an air gap 4, can be seen clearly. The air gap 4 advantageously enables light to be guided through the optical structure 100 by means of total reflection.

The wedge-shaped gap 9 between the enclosure 6 and the enclosed structure 3 is filled either with air or with printing ink.

Not shown is the second half 2 (see Figure 2(b)).

Figure 2(b) shows the optical structure 100 of Figure 2(a) on which the second half 2 is printed. Here it can be easily seen that the first half 1 is a concave lens and that the second half 2 is a convex lens. With the enclosed structure 3, the optical structure 100 can serve, for example, as an eyeglass lens of a pair of augmented reality glasses.

Figure 2(c) shows a detail of the optical structure 100 of Figure 2(b). An opening 7 is clearly visible, which provides access to the air gap 4 between the enclosed structure 3 and the first half 1. For example, light can be coupled or introduced through the opening 7.

Figure 3 shows a detail of a lateral section through the optical structure 100, showing the holder 8 with the recess 8' and the first half 1 , which is securely arranged with the lug T in the recess 8'. Concluding with the outer edge of the first half 1 is printed the enclosure 6, which protects the enclosed structure 3 laterally from damage. The spacer 5, which distances the encapsulated structure 3 from the first half 1 and thus creates an air gap 4, can be seen clearly. The air gap 4 advantageously enables light to be guided through the optical structure 100 by means of total reflection.

The wedge-shaped gap 9 between the enclosure 6 and the enclosed structure 3 is filled either with air or with printing ink. In addition to the embodiment shown in Fig. 2(a), a further spacer 5' can be seen here, which provides a further air gap 4' between the second half 2 and the enclosed structure 3. The further spacer 5' is printed and preferably bonded to the enclosed structure 3. It can be clearly seen that the enclosure 6 is flush with the second half 2.

The terms for air gap 4 and further air gap 4' are interchangeable. This means that further air gap 4' as shown here can also be air gap 4. Thus, it is conceivable that air gap 4 is arranged at the location of further air gap 4', i.e. between second half 2 and enclosed structure 3. For this purpose, it is conceivable that the enclosed structure 3 is not spaced from the first half 1, but is arranged to rest directly thereon.

The terms for the spacer 5 and the further spacer 5' are interchangeable in. That is, further spacer 5' as shown here can be spacer 5 as well.

KEY TO FIGURES

1 First half

1’ Lug 2 Second half

3 Enclosed structure

4 Air gap

4’ Further air gap

5 Spacer 5’ Further spacer

6 Enclosure

7 Opening

8 Holder

8’ Recess 9 Gap

100 Optical structure