Thin film encapsulation within eyeglass lenses

Abstract

The present disclosure relates to an ophthalmic lens comprising a first lens portion attached to a second lens portion, with a cylindrical interface between the first lens portion and the second lens portion, and a film interposed between the first lens portion and the second lens portion at the cylindrical interface. The present disclosure also relates to a method of manufacturing an ophthalmic lens, the method comprising interposing a film between a first lens portion and a second lens portion at a cylindrical interface between the first portion and the second portion.

Description

[0001] This application is a divisional application of patent application No. 202280013688X, filed on February 28, 2022, entitled "Thin Film Encapsulation in Eyeglass Lens". Technical Field

[0002] This disclosure relates to spectacle lenses having an encapsulation film and lens manufacturing and / or film encapsulation technologies for producing spectacle lenses having an encapsulation film. Background Technology

[0003] Eyeglass lenses are typically manufactured using lens grinding or injection molding techniques. The injection molding process involves injecting molten material into a mold under high pressure. The mold is either a blank shape (creating a lens 'blank' for further shaping the inner surface to produce the final lens) or a desired, precise profile of the eyeglass lens, including both inner and outer curvature profiles. After a brief cooling period, the lens is complete. Due to its simplicity and speed, injection molding is the preferred technique for high-volume, stock lenses such as sunglasses. For more customized applications, lens grinding is favored. The lens grinding process begins with a lens 'blank' having a convex outer (world-facing) surface and a flat or concave eye-facing surface. The profile of one or more curved surfaces of these blanks is typically spherical or spherical-cylindrical. The inner surface is then ground to the desired curvature profile and polished using specialized machinery. The eyeglass lens is then edged to the desired edge profile for fitting into a frame, completing the eyeglasses. With the advent of 3D printing (or additive manufacturing) technology, eyeglass lenses with fully customized curvature and edge profiles can also be 3D printed.

[0004] Laminating thin films onto or encapsulating them within eyeglass lenses is desirable for a variety of purposes. For example, the augmented reality (AR) industry (including eye-tracking applications) desires holographic optical elements (HOEs) that can be produced on thin polymer films and then attached to or encapsulated within eyeglass lenses.

[0005] Existing methods exist for encapsulating films within or laminating films onto eyeglasses. For example, US-2015 / 0131047A1 details a process for directly laminating a cellulose acetate laminate film onto eyeglasses of varying profiles for use in safety glass. US-2017 / 0068095A1 describes numerous techniques. In a first technique, the lens is injection molded, thereby creating a mold with a cavity to place the HOE photopolymer film prior to casting. Eyeglass material is then injected into the mold, encapsulating the HOE within. A second technique encapsulates the HOE between two half-lenses, comprising the rear and front portions of the eyeglass lens. The HOE is sandwiched at the interface of the two lens components. In a third method, the photopolymer film is directly laminated onto the concave inner surface of the eyeglass lens.

[0006] Known methods involve complex manufacturing techniques or the risk of film deformation and / or delamination. Therefore, a less complex manufacturing technique is desired to integrate the film with eyeglass lenses without such significant difficulties. Summary of the Invention

[0007] In view of this background, a spectacle lens according to claim 1 and a method for manufacturing a spectacle lens according to claim 8 are provided. A technique for producing a spectacle lens with an encapsulating film and a resulting spectacle lens with the encapsulating film are provided, thereby minimizing stress and deformation. This is achieved by providing a film at a cylindrical interface between two parts of the spectacle lens.

[0008] It has been found that when a thin film is encapsulated in a lens, many stresses and deformations are caused by lamination on curved surfaces, and particularly on surfaces curved across two axes, as is the case with typical eyeglass lenses. Laminating a thin film directly onto a surface with spherical curvature (or other curvature profiles across two axes, which are typically chosen to be of minimum thickness) creates elastic stresses in the film, leading to deformation and delamination.

[0009] In contrast, it has been found that such stresses are avoided when laminating a thin film onto a cylindrical surface. For completeness, it should be noted that a cylindrical surface means that the surface has the shape of a portion of a cylinder along its elongation axis. In other words, the surface is curved along one dimension (e.g., circular or elliptical) but straight (or flat) along the perpendicular dimension. Cylindrical interfaces are highly unconventional, especially because they do not conform to the shape of eyeglass lenses, and are therefore considered non-compact. However, the cylindrical interface can still provide a low thickness without difficulty in lamination.

[0010] Therefore, eyeglass lenses can be manufactured using two component parts, with a thin film encapsulated between the two component parts. Thus, two parts can be used to produce the lens: a rear (facing the eye) part and a front (facing the world) part. The interface between the two parts has the cylindrical shape discussed above. In other words, a cross-section taken along a plane (preferably parallel to the major axis, which is usually horizontal) shows the interface as curved (e.g., a circular or elliptical segment). The cross-section along a vertical plane, usually parallel to the minor axis (usually vertical), is preferably flat or straight. Limiting the curvature on the minor axis (preferably zero) allows for the thinnest stack and imposes minimal restrictions on the choice of inner and outer curvature.

[0011] In simple cases, lenses with a spherical or spherocylonic outer contour (typically used for standard prescription eyeglass lenses) can be segmented or formed into two component parts, with the interface between the two parts having a cylindrical contour. Laminating a thin layer onto a cylindrical surface results in low deformation and delamination risk. Because this surface has curvature only along one axis, it does not generate the same stress on the film compared to lamination on a spherical surface.

[0012] The two parts can be manufactured using any technology, such as injection molding, typically used for mass production; grinding and polishing, typically used for more customized requirements; or 3D printing. Optionally, for example, by placing a film within a mold before casting, the film can be integrated with one of the lens parts (so that it is located at the interface formed). After the two lens parts are combined with the film inserted between the two lens parts (regardless of whether any lens part is integrally formed with the film), the resulting spectacle lens can be considered a blank. The eye-facing surface of the blank can then be ground to form the spectacle lens.

[0013] Typical eyeglasses have meniscus lenses, meaning the surface facing the eye is concave, while the surface facing the world is convex. Typical eyeglasses also exhibit a certain aspect ratio (thus defining the major and minor axes), whereby the horizontal extent (major axis) of the lens is greater than its vertical extent (minor axis). This aspect ratio advantageously allows the eyeglass lens to be divided into two parts for the purpose of encapsulating a thin film.

[0014] The thin film is preferably anisotropic. Typically, the thin film comprises a holographic optical element (HOE), which can act as a reflective or transmissive element. In some embodiments, the HOE can act as a plane mirror or a planar transmission hologram without optical power. Alternatively, the HOE can be augmented with optical power such that the total optical power of the HOE is the sum of the optical power of the hologram and the optical power resulting from the curvature of the cylindrical interface.

[0015] The thin film can initially be a photosensitive material, and a HOE can be formed by recording a hologram on the photosensitive material. In some embodiments, a hologram can be recorded when the photosensitive material is placed on a planar substrate and then laminated onto a cylindrical interface. In this case, it is advantageous to record the hologram to compensate for the cylindrical interface. In other embodiments, a hologram can be recorded when the photosensitive material is applied to the cylindrical interface. In this case, no additional compensation for the cylindrical interface is required.

[0016] Combinations of features from various aspects or from various aspects can also be considered, among which such combinations are feasible. Attached Figure Description

[0017] This disclosure can be implemented in various ways, and preferred embodiments will now be described by way of example only and with reference to the accompanying drawings, in which:

[0018] Figure 1 shows a perspective view of an existing eyeglass lens;

[0019] Figure 2A A perspective view of an eyeglass lens according to this disclosure is depicted;

[0020] Figure 2B Showed through Figure 2A A cross-sectional view of the eyeglass lens;

[0021] Figure 3A Depicting Figure 2A The components of eyeglass lenses;

[0022] Figure 3B schematically shown Figure 3A The assembly form of the component parts;

[0023] Figure 4A A perspective view of an example alternative eyeglass lens is shown;

[0024] Figure 4B Showed through Figure 4A A cross-sectional view of the eyeglass lens;

[0025] Figure 5A Depicting Figure 4A The components of eyeglass lenses;

[0026] Figure 5B schematically shown Figure 5A The assembly form of the component parts;

[0027] Figure 6A An example circular lens blank is depicted;

[0028] Figure 6B It shows the bisection based on the planar interface. Figure 6A An exploded view of the lens blank;

[0029] Figure 6C This demonstrates the bisection based on the cylindrical interface. Figure 6A An exploded view of the lens blank; and

[0030] Figure 7 This schematically illustrates the relationship between the radius of curvature and the center thickness on a world-facing lens component of a certain size.

[0031] The accompanying drawings are schematic in nature, and exact dimensions and structures should not be inferred unless explicitly shown or described. Detailed Implementation

[0032] Referring first to Figure 1, a perspective view of a conventional spectacle lens 101 is shown, having a surface 102 facing the eye and a surface 103 facing the world. This is a simple zero-magnification spherical lens (similar to other spectacle lenses shown in the figures) and is for illustrative purposes only. It should be understood that this embodiment can be applied to other spectacle lenses, including prescription spectacle lenses and spectacle lenses with different curve profiles.

[0033] Typical eyeglasses use meniscus lenses, meaning that the surface 102 facing the eye is concave and the surface 103 facing the world is convex. As described above, the illustrated spectacle lens 101 has a spherical radius of curvature on both its inner and outer surfaces. Simple spherical lenses are commonly used for zero-magnification stock lenses in applications including sunglasses and ski goggles. In this application, both the front and rear surfaces have spherical curvature, with the two curvature profiles being concentric. For prescription lenses, cylindrical magnification is typically added to the rear lens surface 102 to correct astigmatism. However, the surface is typically spherocylindrical (as described in "Principles of Ophthalmic Lenses," M. Jalie, Association of British Dispensing Opticians College of Education). The typical dimensions of spectacle lenses shown are for illustrative purposes only.

[0034] Figure 1 also shows an axis, which will be used consistently in the other figures of this disclosure. The spectacle lens 101 typically has a major axis in the horizontal (x) direction and a minor axis in the vertical (y) direction. The depth (z) dimension of the spectacle lens 101 is typically negligible (or at least significantly smaller, typically at least 10 times) compared to its other dimensions.

[0035] The outer (world-facing) surface of eyeglass lenses typically has a spherical curvature, often referred to as the "base curvature." This base curvature serves the functional purpose of providing optimal optical performance, while also enhancing the lens's aesthetics and reducing its weight. A 6-diopter curve front surface (equivalent to approximately 83mm of curvature radius) is considered the 'optimal form' for providing the best peripheral vision (based on empirical data). For aesthetic reasons, reading glasses and fashion lenses often have a slightly flatter surface, with a 4-diopter base curve being common.

[0036] Regarding additional information (but again, not a specific limitation), it should be noted that the illustrated spectacle lens 101 has a horizontal lens extent of 55 mm (along the x-axis) and a vertical lens extent of 32 mm (along the y-axis). The lens has a uniform thickness of 2 mm, with an inner (facing the eye) radius of curvature of 150 mm (approximately 3.3 diopters) and an outer (facing the world) radius of curvature of 152 mm. This is typical for a zero-power stock lens, but as mentioned above, 6-diopter or 4-diopter lenses may be more common. Prescription lenses will have different thickness profiles.

[0037] Now for reference Figure 2A The image depicts a perspective view of a spectacle lens 201 according to the present disclosure. According to the present disclosure, the spectacle lens is formed as two parts, with a thin film encapsulated within the lens, wherein the interface between the two parts is a cylindrical profile. The parameters of the thin film are generally well understood, but in this context, the thickness of the thin film can be approximately 100 micrometers or less. The thin film is typically a low-absorption, optically transparent (or transparent) low-haze film, suitable for incorporation into the lens without significantly affecting perspective. A reference plane 202 at the center of the spectacle lens is highlighted in the xz plane. Also referenced is... Figure 2B This shows the passage through reference plane 202. Figure 2A The cross-section of the eyeglass lens. Here, the cylindrical interface profile 203 between the two component parts is shown in dashed lines.

[0038] The two component parts are typically manufactured separately, but may optionally be formed from separate eyeglass lenses. Cylindrical surfaces on the lenses or lens components are not common. Cylindrical surfaces between the two lens components can be created by grinding or custom molding (injection molding). Optionally, 3D printing can be used to manufacture the lens components. Manufacturing lens components with cylindrical interfaces is not a standard technique. However, injection molding (e.g., with plastics), grinding, or 3D printing can be used. Standard lens grinding and molding can use diamond turning, which typically results in spherical surfaces, but cylindrical surfaces can be achieved using this and other techniques.

[0039] Next reference Figure 3A It depicts Figure 2A The components of the eyeglass lens. These components include: a first component portion (incorporated into the surface facing the eye) 301; and a second component portion (incorporated into the surface facing the world) 302. The interface between the first component portion 301 and the second component portion 302 has a cylindrical shape (e.g., Figure 2B As shown, the interface is curved (in this case, an arc segment) in the xz plane and flat in the yz plane (and also flat in the xy plane).

[0040] In this example, the cylindrical shape is curved along the x-axis, particularly with a radius of curvature of 151 mm, and the profile is flat along the y-axis. Therefore, it can be seen that using a purely cylindrical interface between the two parts allows for the formation of two components, each with dimensions of 55 mm (x) × 32 mm (y) (i.e., the major and minor axes of the spectacle lens are the same), which are combined to form the final spectacle lens. The center thickness of each component is approximately 1.3 mm.

[0041] A thin film with the same size (55mm in the x direction and 32mm in the y direction) and contour as the glasses. Figure 3A (Not shown) The film is laminated onto a cylindrical interface between the first component portion 301 and the second component portion 302. Then, when the first component portion 301 and the second component portion 302 are attached to each other, the film is completely encapsulated within the spectacle lens. Lamination on a cylindrical surface avoids the deformation associated with lamination on a spherical surface. The interface is preferably a perfect cylinder, but can also be a partially spherical cylinder or a tortuous surface, as long as any deviation from the shape of a perfect cylinder is negligible. The closer the interface is to a perfect cylinder, the lower the stress in the film. The film is preferably a holographic optical element (HOE) or a photosensitive material suitable for recording HOEs therein.

[0042] As described above, the cylindrical interface between the first component portion 301 and the second component portion 302 is flat along one axis. Therefore, the cylindrical interface exhibits the same geometric constraints along this axis as when using a flat film. However, since spectacle lenses typically have a significant aspect ratio, this constraint becomes less important if it applies only to the shorter (shorter) axis of the spectacle lens, as will now be discussed further below.

[0043] Attaching a thin film to the cylindrical surface of one of the lens components can be achieved in several ways. Lamination of the film may not require adhering the film to one or both surfaces of the cylindrical interface (the first component portion 301 and the second component portion 302 can simply be attached to each other with the film between the first and second component portions), but can provide additional adhesion. The HOE can be a photopolymer, such as Bayfol (RTM) HX (sold by Covestro AG), which typically has a substrate about 60 micrometers thick and a polymer layer about 20 micrometers thick. One side of the photopolymer is then typically an adhesive film, which adheres to the glass or plastic once laminated onto the surface using a roller (or similar). Alternatively or additionally, adhesive, double-sided tape, vacuum treatment, heat treatment, or pressure treatment can be used to adhere the HOE to the substrate. The HOE can also be a silver halide film, and the above techniques can also be used to adhere the film to the substrate surface. The choice of lens material helps to improve adhesion; for example, polycarbonate can provide better adhesion. The film typically does not extend completely to the edge of the cylindrical interface. This allows for good encapsulation (no moisture ingress) if there is a good adhesive seal around it.

[0044] refer to Figure 3B It schematically demonstrates Figure 3A The assembled spectacle lens 303 is shown as a component portion. A thin film 304 encapsulated between the first component portion 301 and the second component portion 302 is also shown. Thus, the completed spectacle lens 303 is formed from two component portions mated together by a cylindrical interface, with the thin film 304 situated between the components.

[0045] The eye-facing component (first component portion 301) can be molded in the desired shape for an eyeglass lens. More typically, the eye-facing component is molded as a lens blank, wherein the component will have a cylindrical profile on its front surface (to be incorporated into the world-facing component 302), but the rear surface can be flat or have some arbitrary surface curvature. The first component portion 301, the second component portion 302, and the film 304 are then combined to form an eyeglass lens 303 as a lens 'blank' with an embedded HOE.

[0046] Once the assembled spectacle lens 303 is formed in this manner, it will present itself as a circular profile lens blank, and the rear surface can be ground into a standard lens blank to produce the final lens. To fit the spectacle, the front and rear curvatures are typically ground (grinded around the edges) to fit the spectacle frame. This process can be performed on the first component portion 301 and the second component portion 302 before or after film encapsulation and assembly. The grinding process is more vigorous than edge grinding when the front and / or rear surfaces are ground to a certain curvature, and preferably, if desired, this process is performed on the first component portion 301 and / or the second component portion 302 before film encapsulation and assembly.

[0047] Therefore, the component facing the world is typically formed to include a spherical front surface, usually with a desired basic curvature, and a rear surface with a cylindrical profile. The component facing the eye can be formed to include a front surface and a rear surface with a cylindrical profile. This rear surface can then be formed to have the curvature desired in the final prescription. Alternatively, the rear surface can remain flat (or have any curvature) to produce a lens blank, whereby further grinding of this surface will be used to set the prescription.

[0048] Now for reference Figure 4A A perspective view of an example alternative spectacle lens 401 is shown. This alternative spectacle lens 401 does not have a cylindrical interface between the two lens components, but rather a planar interface. This is shown for comparative purposes. A reference plane 402 at the center of the spectacle lens is highlighted in the xz plane. Also referenced... Figure 4B This shows the passage through reference plane 402. Figure 4A The cross-section of the spectacle lens. Here, the planar (flat) interface profile 403 between the two component parts is shown in dashed lines.

[0049] Now for reference Figure 5A It depicts Figure 4A The components of the eyeglass lens. These components include: a first component portion (incorporated into the surface facing the eye) 501; and a second component portion (incorporated into the surface facing the world) 502. The interface between the first component portion 501 and the second component portion 502 has a flat, planar shape (e.g., Figure 4B As shown, the shape is flat in all xz, yz, and xy planes. A thin film (not shown) can be encapsulated between the first component portion 501 and the second component portion 502. Lamination at the planar interface between the first component portion 501 and the second component portion 502 is simple.

[0050] Finally, refer to Figure 5B The illustration shows the composition of Figure 5AThe assembled spectacle lens 503 is formed from the component parts. This shows how the first component part 501 and the second component part 502 are combined to manufacture the final spectacle lens 503. It can be seen that the joint between the first component part 501 and the second component part 502 is oriented toward the center of the lens 503 and away from the edge of the spectacle lens 503.

[0051] Therefore, the horizontal range of the outer (world-facing) portion of the same spectacle lens is limited by using a planar intersection rather than a cylindrical interface, as shown in spectacle lens 503. This limits the possible size of the film that can be encapsulated within the spectacle. While small areas of film can be laminated and encapsulated on this surface, any film encapsulated within the spectacle preferably extends close to the edge of the lens. This prevents visible edges and facilitates the lamination process. If a planar intersection (as shown in Figures 4 and 5) is chosen, but the film size needs to match the size of the spectacle, this can be achieved by making the entire spectacle thicker or by reducing the curvature profile. Thus, it can be seen that a cylindrical (curved) interface between the two component parts allows for the use of a thinner stack while also providing maximum flexibility in the choice of curvature profile. Therefore, the final encapsulated spectacle lens is thinner, lighter, cheaper, and more consumer-friendly than encapsulated spectacle lenses manufactured using different methods.

[0052] These benefits will refer to... Figure 6A To further discuss this example, the figure depicts an exemplary circular lens blank. This shows a lens blank with a diameter of 70 mm, an inner radius of curvature of 250 mm, a thickness of 2.6 mm, and an outer radius of curvature of 252.6 mm (thus, a perfectly concentric surface).

[0053] Next reference Figure 6B It demonstrates the bisection based on the planar interface. Figure 6A An exploded view of the lens blank. The lens blank is divided into two component parts with a planar interface (e.g., as discussed with reference to Figures 4 and 5), resulting in a center thickness of 1.3 mm for each component part. As discussed above, the planes do not intersect to reach the full extent of the 70 mm lens blank used in this example. In the resulting component, the diameter of the part facing the outside world is less than 70 mm. Therefore, if a film is to be laminated at the interface between the two parts, the size of the film is limited to the size of the part facing the outside world.

[0054] Now for reference Figure 6C This demonstrates the bisection based on the cylindrical interface. Figure 6AAn exploded view of the lens blank. The use of a cylindrical rather than planar interface bisecting is also discussed with reference to Figures 2 and 3 above. Since the interface is flat along one axis (vertical), the degree of constraint on the world-facing component along one axis is the same as that of the planar interface. However, the world-facing component is no longer confined to another (horizontal) axis. This is advantageous because most eyeglass components have an aspect ratio, whereby the horizontal axis is longer than the vertical axis, as shown with reference to Figures 2 and 3.

[0055] Now for reference Figure 7 This diagram schematically illustrates the relationship between the radius of curvature and the center thickness of a world-facing lens component of a given size. Assuming a spherically curved world-facing component with radius of curvature R and center thickness T, the radius x of the world-facing component is given by the following expression:

[0056]

[0057] Therefore, it can be seen that the size of the component facing the world is limited by two factors: (1) the thickness of the lens; and (2) the radius of curvature of the outer surface. Thus, fitting a larger film at the planar interface between the component facing the eye and the component facing the world implies making the lens thicker or reducing the radius of curvature. For practical and / or aesthetic reasons, both of these situations may be undesirable for eyeglass frames.

[0058] Generally, and in the first aspect, a spectacle lens can be contemplated, comprising: a first lens portion attached to a second lens portion, the first lens portion and the second lens portion having a cylindrical interface; and a film inserted at the cylindrical interface between the first lens portion and the second lens portion. An optical device, such as optical glass, a visual headset, or the like, can also be contemplated, comprising one or more spectacle lenses according to this aspect.

[0059] In a second aspect that can be combined with the first aspect, a method for manufacturing spectacle lenses can be considered. The method includes inserting a thin film between the first lens portion and the second lens portion at a cylindrical interface between the first lens portion and the second lens portion. Thus, the resulting spectacle lens (which may involve the first lens portion and the second lens portion combined with the thin film inserted therebetween) can be formed from the spectacle lens of the first aspect (as discussed above) or an intermediate product, such as a spectacle lens blank, from which the final spectacle lens can be formed.

[0060] Depending on any one (or two) aspect, a number of optional and / or preferred features can be considered. For example, spectacle lenses can typically be elongated and / or can have a (longer) major axis (typically horizontal) and a (shorter) minor axis (vertical). For example, spectacle lenses can generally be trapezoidal (or rectangular), elliptical, or a shape between these two options. In any case, the cylindrical interface preferably has a curved profile across the major axis of the spectacle lens. Then, the cylindrical interface advantageously has a straight (or flat) profile across the minor axis. In some embodiments, the spectacle lens has a spherical or spherocylonic outer profile.

[0061] Advantageously, the first lens portion has a first cylindrical surface, and the second lens portion has a second cylindrical surface. The second cylindrical surface is then advantageously arranged to mate with the first cylindrical surface to provide a cylindrical interface.

[0062] The following section will discuss further generalized aspects. First, more specific details based on the embodiments will be considered.

[0063] As described above, the thin film is typically a holographic optical element (HOE), an optical component that uses the principle of diffraction to generate a holographic image, and can be understood as a type of hologram. HOEs are typically recorded on a flat or planar surface. In this case, if the thin film is to be laminated or encapsulated into an eyeglass lens, resulting in a HOE with a curved profile, compensation for this curvature and / or the rear (facing the eye) lens component portion (which may refract the replay light before it reaches the HOE) is incorporated into the recording setup. By compensating for this curvature, the HOE will correctly reproduce its final curved state.

[0064] For example, if the spectacle lens component, as described herein, has a suitable low-birefringence plastic or glass, the HOE can preferably be recorded directly (in the dark) onto the film when it is laminated onto one of the lens components (before or after encapsulation). No compensation for the curvature of the spectacle lens or HOE is included in the recording, and the optimal optical performance of the HOE is maintained in all cases. However, if the HOE is not fully encapsulated before recording (or the playback position may subsequently be changed), compensation for angular variations introduced by the rear (facing the eye) lens component may still be desired. Furthermore, it may be advantageous to avoid re-lamination of the film between recording and implementation (i.e., removing the film from a flat recording surface and re-laminating it onto a curved surface). This avoids re-lamination problems such as de-registration and avoids added stress on the film. However, from a practical standpoint, implementation is challenging.

[0065] Alignment of the optical system is desirable, especially for augmented reality (AR) applications, to provide viewers with high-quality (aberration-free, high-resolution) virtual images. The optical center of the HOE is ideally aligned within the spectacle lens, preferably with an accuracy of + / -0.1 mm relative to the optical axis of the projector or light source. Therefore, if it is necessary to remove the HOE from a flat surface (on which it is recorded) and re-laminate it onto a curved surface for encapsulation within the spectacle, it is crucial that lamination be as easy as possible to allow for precise alignment of the HOE. The cylindrical inner surface described herein allows for easier lamination and therefore easier alignment than a spherical inner surface. The HOE can alternatively be recorded on a roll-to-roll system and laminated during an automated process. Again, this procedure is simpler on a cylindrical surface than on a spherical surface.

[0066] The optical quality and stability of the HOE are also relevant to AR applications. Any variation in the position or thickness of the HOE will negatively impact the quality of the virtual image. The HOE is an optical element, and the accuracy of optical elements is typically specified as one wavelength or less. This means that if the HOE changes from its nominal position by more than one light wavelength, the image will be affected. For example, this variation can occur if lamination on a spherical surface causes wrinkles or stress in the HOE. The surface on which the holographic layer is laminated is expected to have optically high smoothness, positional stability, and a known curvature, and the hologram is expected to remain conformal to the surface after encapsulation for optimal image quality. It should be noted that some existing methods for laminating thin films inside eyeglasses (e.g., cellulose acetate films for laminated safety glass, photochromic films for sunglasses) do not require precise positional accuracy during lamination because the films are primarily isotropic (i.e., all positions / orientations are the same).

[0067] Returning to the general aspects discussed above, further details can be considered. Advantageously, the thin film comprises holographic optical elements. Preferably, the thin film is primarily or largely anisotropic (i.e., all or at least most or the vast majority of its positions / orientations are different).

[0068] In some embodiments, the holographic optical element is configured to act as a plane mirror. In this case, the holographic optical element itself may not contribute to the optical power. The total optical power of the HOE can then be determined by the cylindrical curvature of the inner surface on which the HOE is laminated. Spectacular lenses exhibit optical power in the real world, as determined solely by the curvature of the inner and outer surfaces of the spectacular lens.

[0069] Alternatively, the spectacle lens can be configured such that the total optical power of the holographic optical element is determined by the sum of the optical power of the hologram of the holographic optical element and the optical power generated due to the curvature of the cylindrical interface. The HOE can then function as a reflective dynamic optics element (as is typically the case in AR applications).

[0070] In some embodiments, the thin film comprises a photosensitive material. A hologram can then be recorded on the photosensitive material to form a holographic optical element. In some cases, recording a hologram on the photosensitive material may include: providing the photosensitive material on a planar substrate; and, when on the planar substrate, recording the hologram on the photosensitive material to compensate for the optical power of the cylindrical interface. This can thereby provide a holographic optical element, which can then be applied to the cylindrical interface. In other cases, recording a hologram on the photosensitive material may include: applying the photosensitive material to the cylindrical interface; and, when on the cylindrical interface, recording the hologram on the photosensitive material.

[0071] Although specific embodiments have now been described, those skilled in the art will understand that various modifications and changes are possible. It should be understood, of course, that variations in design distances, dimensions, curvatures, angles, and component sizes are possible without altering the fundamental disclosure. Furthermore, additional optical components can be incorporated to redirect and / or process light as needed.

[0072] While a curved cylindrical shape spanning the long (horizontal) axis and an interface profile straight across the short (vertical) axis are preferred, the method according to this disclosure can be implemented using a curved cylindrical shape spanning the short (vertical) axis and an interface profile straight across the long (horizontal) axis. Furthermore, the curved cylindrical shape can be at an angle, for example, 45 degrees, to the long and short axes of the eyeglass lens component shape.

[0073] In some applications, the interface between two eyeglass lens components can be curved along two axes. However, in this case, the interface curvature on the minor axis, or vertical axis, is minimized, where the ideal curvature is zero. In other words, any deviation from zero curvature on the minor axis is negligible. Any curved shape (e.g., across the major axis) is possible.

[0074] The typical HOE in an AR system is a reflection hologram. However, a transmission HOE can be used alternatively or concurrently. Transmission AR applications are well-known in practice. A transmission HOE may have optical power in some cases, but alternatively may not, and can then be called a planar transmission element or hologram (a transmissive equivalent of a plane mirror).

[0075] The outer shape (profile) of the eyeglass lens is preferably spherical or spherocylonic, but in some embodiments it may be tortuous or aspherical. Such shapes are less common and are generally more expensive to manufacture.

[0076] The manufacturing process discussed above first forms two lens component parts, and then encapsulates a film (HOE) between the two lens component parts. However, these steps can be integrated, and specifically, the film (HOE or a photosensitive material that can form an HOE) can be integrally formed with either the first or second lens component part. It is advantageous to form the lens components such that the film is located at the interface. This can be achieved, for example, if at least one of the lens component parts is formed by injection molding. Then, the film can be incorporated into the casting process when either of the component parts is produced. The film is placed such that it abuts against the cylindrical side (interface) of the lens component mold. Resin is then injected, and the film is bonded to the component by casting (rather than lamination). As a result, two lens components can be formed, but one lens component will already have the film fused at the interface.

[0077] For example, further options may be considered regarding the general terminology discussed above. For example, in an embodiment, the film may be integrally formed with either a first lens portion or a second lens portion. One of the lens components can be considered to have a surface facing the eye (opposite to a cylindrical interface surface). This can be formed in any shape. After combining the two lens portions with the film encapsulated between the two lens portions, the resulting product can be considered an eyeglass lens blank. The eye-facing surface of the eyeglass lens blank can be milled to form an eyeglass lens.

[0078] The eyeglass lenses (or lenses) according to this disclosure can generally be used in AR applications. Applications other than AR may include eye tracking and reflective filters for specific wavelengths of light (e.g., infrared light or lasers to avoid interference or damage). The eyeglass lenses according to this disclosure can also be used (but more difficult) in virtual reality (VR) applications.

Claims

1. A method for manufacturing spectacle lenses for augmented reality glasses, the method comprising the following steps: A first lens portion is formed, the first lens portion including a cylindrical surface and a surface facing the eye; The thin film is applied to the cylindrical surface; A second lens portion is formed and applied to the cylindrical surface and the film, such that the film is interposed between the first and second lens portions at the cylindrical interface between the first and second lens portions. The thin film is a holographic optical element, which is recorded to compensate for the light power of the cylindrical surface.

2. The method of claim 1, wherein the holographic optical element is recorded to compensate for the curvature of the cylindrical surface.

3. The method according to claim 1, wherein the first lens portion is formed by injection molding.

4. The method of claim 1, wherein the second lens portion is formed by casting.

5. The method according to claims 1 to 4, wherein after being applied to the first lens portion, the second lens portion includes a cylindrical surface, the cylindrical surface of the second lens portion being arranged to mate with the cylindrical surface of the first lens portion to provide the cylindrical interface.

6. The method according to claims 1 to 4, wherein the spectacle lens comprises a long axis and a short axis, and the cylindrical interface has a curved profile across the long axis.

7. The method according to claims 1 to 4, wherein the cylindrical interface has a straight profile across the short axis.

8. The method according to any one of claims 1 to 4, wherein the thin film comprises a photosensitive material.

9. The method according to any one of claims 1 to 4, further comprising: The first lens portion and the second lens portion are combined with the inserted film to form an eyeglass lens blank; The surface of the eyeglass lens blank facing the eye is ground.

10. A spectacle lens for augmented reality glasses, the spectacle lens comprising: A first lens portion, comprising a cylindrical surface and an eye-facing surface, is attached to a second lens portion, and a cylindrical interface exists between the first lens portion and the second lens portion; and A thin film is inserted at the cylindrical interface between the first lens portion and the second lens portion, wherein the thin film includes a holographic optical element that is recorded to compensate for the optical power of the cylindrical surface.

11. The spectacle lens of claim 10, wherein the holographic optical element is recorded to compensate for the light power of the eye-facing surface of the first lens portion.

12. The spectacle lens of claim 10, wherein the holographic optical element is recorded to compensate for the curvature of the cylindrical surface.

13. The spectacle lens according to claim 10, wherein, The second lens portion includes a cylindrical surface, which is arranged to mate with the cylindrical surface of the first lens portion to provide the cylindrical interface.

14. The spectacle lens of claim 10, wherein the spectacle lens comprises a major axis and a minor axis, and the cylindrical interface has a curved profile across the major axis.

15. The spectacle lens of claim 14, wherein the cylindrical interface has a straight profile across the short axis.

16. The spectacle lens according to claims 10 to 15, wherein the spectacle lens is configured such that the total optical power of the holographic optical element is determined by the sum of the optical power of the hologram of the holographic optical element and the optical power generated due to the curvature of the cylindrical interface.

17. The spectacle lens according to claims 10 to 15, wherein the spectacle lens has a spherical or spherical cylindrical outer contour.

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