Method for producing an optical waveguide, optical waveguide and display device having such an optical waveguide
The method addresses alignment issues in optical waveguides by controlling the orientation of reflective deflection surfaces, improving image quality and user experience in spectacle lenses.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- TOOZ TECH GMBH
- Filing Date
- 2025-11-14
- Publication Date
- 2026-05-21
AI Technical Summary
Existing optical waveguides suffer from alignment variations of partially reflective deflection surfaces, leading to image errors and undesirable effects such as prismatic decentering and light scattering, which are exacerbated when used in spectacle lenses for display devices.
A method for manufacturing optical waveguides with controlled orientation of partially reflective deflection surfaces using a base body and insert, where the insert is glued into a recess with oblique surfaces and coated to form deflection surfaces, allowing for precise alignment and reduced orientation variance.
This method reduces image errors and light scattering, enhances the effective exit pupil, increases eyebox size, field of view, brightness, and resolution, and allows for adjustable positioning of the image for user comfort.
Smart Images
Figure EP2025083029_21052026_PF_FP_ABST
Abstract
Description
[0001] patent attorneys
[0002] GEYER, FEHNERS & PARTNER
[0003] Munich - Jena
[0004] tooz technologies GmbH
[0005] Attorney's file: PAT 4377 / 072-PCT
[0006] Method for manufacturing an optical waveguide, optical waveguide and display device with such an optical waveguide
[0007] The present invention relates to a method for manufacturing an optical waveguide, an optical waveguide and a display device with such an optical waveguide.
[0008] Such an optical waveguide can be combined with two lenses (a push and a pull lens) to form a spectacle lens, with the optical waveguide positioned between the two lenses. When the spectacle lens is used as intended, the pull lens is closer to the user's eye than the push lens. Since collimated light with a focal plane at infinity is generally used to transmit the generated image through the optical waveguide, the pull lens typically has a negative refractive power to shift the focus of the virtual image towards near vision. If farsightedness correction is required, the pull lens may have a positive refractive power. For viewing the surroundings, the influence of the pull lens is at least partially compensated for by the positive refractive power of the push lens.
[0009] The optical waveguide can have an entrance section and a deflection section spaced apart from it along a predetermined direction, with, for example, a single deflection surface (single-mirror design) or multiple deflection surfaces (multi-mirror design; for example, nine partially reflective deflection surfaces). Light coupled in via the entrance section is guided by the waveguide along the predetermined direction to the deflection section, from which it is deflected by the partially reflective deflection surface(s) to exit the optical waveguide. The use of multiple partially reflective deflection surfaces allows for a reduction in the thickness of the optical waveguide while maintaining or increasing the exit pupil compared to a single-mirror design with a single partially reflective deflection surface.
[0010] The optical fiber is often manufactured using an injection molding process, which enables mass production of optical fibers with partially reflective deflection surfaces. However, variations in the orientation of these surfaces relative to each other can frequently occur within the optical fiber. If the optical fiber is used to guide an image entering the fiber through the entry section to the deflection section and deflect it so that it exits the fiber, patent attorneys
[0011] GEYER, FEHNERS & PARTNER
[0012] Munich - Jena
[0013] At point 2, the alignment variations lead to undesirable image errors in the image emerging from the optical waveguide. In other words, the variations in the alignment of the partially reflective deflecting surfaces relative to each other result in a radiometric image with stitching errors – rendering the radiometric imaging unusable.
[0014] Furthermore, to create the partially reflective deflection surfaces, recesses with inclined surfaces are produced during injection molding. These inclined surfaces are coated with a partially reflective material, and then the recesses are filled, for example, with an adhesive that is not ideally index-matched to the optical fiber substrate. This leads to a prismatic effect, which can result in an additional decentered imaging of the radiometric image.
[0015] Furthermore, an injection mold has minimum radii due to the tooling. These minimum radii in the injection mold lead to imperfect shaping of the edges of the surfaces on which a partially reflective coating is applied to form the partially reflective deflection surfaces. This leads (especially with a non-ideal index matching of the adhesive to fill the resulting depressions) to undesirable light scattering at the partially reflective coating (at the partially reflective deflection surfaces). When the optical fiber is used in a spectacle lens for a display device placed on a user's head, this can lead to a "horizontal smearing" against the direction of light propagation towards the deflection surfaces.
[0016] Based on this, the object of the invention is to provide a method for manufacturing an optical waveguide, whereby an optical waveguide can be produced in which the aforementioned difficulties are avoided as far as possible. Furthermore, such an optical waveguide and a display device incorporating such an optical waveguide are to be provided.
[0017] The invention is defined in independent claims 1, 13, 14, 15 and 16. Advantageous embodiments are specified in the dependent claims.
[0018] A method is provided for manufacturing an optical waveguide comprising an entrance section and a deflection section spaced apart from it along a predetermined direction, the deflection section having two partially reflective deflection surfaces, and which guides light coupled in via the entrance section along the predetermined direction to the deflection section, from which it is deflected by means of the two partially reflective deflection surfaces to exit the optical waveguide, wherein the method comprises the following steps: Patent attorneys
[0019] GEYER, FEHNERS & PARTNER
[0020] Munich - Jena
[0021] 3 - Providing a base body with the entry section and a recess spaced apart from it along the predetermined direction, which extends from a first outer surface of the base body into the base body at an angle of non-zero° to the predetermined direction,
[0022] - Providing a deployment with two outward-facing surfaces,
[0023] - Applying a semi-reflective coating to each of the two outward-facing outer surfaces of the insert,
[0024] - Insert the insert into the recess and glue the insert in the recess in such a way that the two outwardly pointing outer surfaces on which the semi-reflective coatings are applied are oriented obliquely to the predetermined direction and form the two semi-reflective deflection surfaces of the deflection section.
[0025] Furthermore, a method for manufacturing an optical waveguide is provided, which has an entrance section and a deflection section spaced apart from it along a predetermined direction, with two partially reflective deflection surfaces, and which guides light coupled in via the entrance section along the predetermined direction to the deflection section, from which it is deflected by means of the two partially reflective deflection surfaces to exit the optical waveguide, wherein the method comprises the following steps:
[0026] - Providing a base body with the entry section and a recess spaced apart from it along the predetermined direction, which extends obliquely into the base body from a first outer surface of the base body in the predetermined direction and which has two mutually facing inner surfaces, each extending obliquely in the predetermined direction,
[0027] - Applying a semi-reflective coating to the two facing inner surfaces to form the two semi-reflective deflection surfaces of the deflection section, - Filling the recess with an insert and / or an adhesive.
[0028] Furthermore, a method for manufacturing an optical waveguide is provided, which has an entrance section and a deflection section spaced apart from it along a predetermined direction, with at least two partially reflective deflection surfaces, and which guides light coupled in via the entrance section along the predetermined direction to the deflection section, from which it is deflected by means of the at least two partially reflective deflection surfaces to exit the optical waveguide, wherein the method comprises the following steps:
[0029] - Providing a base body with the entry section and a recess spaced apart from it along the predetermined direction, which extends obliquely into the base body from a first outer surface of the base body in the predetermined direction and which the patent attorneys
[0030] GEYER, FEHNERS & PARTNER
[0031] Munich - Jena
[0032] 4 two facing inner surfaces, at least one of which extends obliquely to the predetermined direction,
[0033] - Providing a deployment with two outward-facing surfaces,
[0034] - Applying a partially reflective coating to at least two surfaces from a group comprising the two outer surfaces and the two inner surfaces,
[0035] - Insert the insert into the recess and glue the insert in the recess in such a way that the at least two surfaces on which the partially reflective coating is applied are oriented obliquely to the predetermined direction and form the at least two partially reflective deflection surfaces.
[0036] According to the invention, the deflection section can thus be designed with two partially reflective deflection surfaces (one can also speak of a double mirror) which extend over a region of the base body thickness (at an angle of greater than 0° to the predetermined direction), in particular over no more than 90%, 80%, 70%, 60% or 50% of the base body thickness or over the entire base body thickness.
[0037] The proposed design is suitable for injection molding. For this purpose, a molded part is inserted into the injection mold before the injection of, for example, plastic (e.g., a polymer) to form a recess. The insert can also be manufactured by injection molding. This allows the orientation variance of, for example, nine partially reflective deflection surfaces or more than two partially reflective deflection surfaces in a conventional optical fiber to be reduced to two partially reflective deflection surfaces. Furthermore, in the inventive method, the orientation of the partially reflective deflection surfaces can be controlled and adjusted by controlling and adjusting the outer surfaces of the insert and / or the inner surfaces of the recess, for example, in addition to and separately from the injection molding process.
[0038] Since each of the two partially reflective deflection surfaces is generally larger than each of the nine partially reflective deflection surfaces (or the more than two partially reflective deflection surfaces) described in the example of a conventional optical waveguide with a multi-mirror design, the effective exit pupil of the optical waveguide can be equal to or larger than that of the multi-mirror design. Compared to the single-mirror design, the invention provides a larger effective exit pupil of the optical waveguide. Eyebox size, field of view (FoV), brightness, and resolution can also increase.
[0039] The partially reflective deflecting surfaces are designed in such a way that, through their deflection, the light exits in the direction of a viewer's eye. This applies particularly when the optical fiber is used in a display device that can be placed on a user's head. Patent attorneys
[0040] GEYER, FEHNERS & PARTNER
[0041] Munich - Jena
[0042] 5
[0043] The base body can be provided in such a way that the recess extends completely through the base body as a through-hole.
[0044] Furthermore, the base body can be manufactured using injection molding.
[0045] The insert can be held in the desired orientation during the gluing process.
[0046] The positioning of the insert in the recess during bonding can be adjusted depending on a target value of a predetermined parameter. If the waveguide is intended for a display device to be worn on a user's head, the parameter could, for example, be the user's individual pupil position.
[0047] The extent of the recess in the predetermined direction can be at least 10% greater than the distance between the two outer surfaces of the insert, so that the position of the insert along the predetermined direction and / or the orientation (or position or alignment) of the insert in which the insert is glued is adjustable.
[0048] This makes it possible, for example, to influence the position in which the viewer sees the (virtual) image by adjusting the positioning of the insert within the recess. In other words, the position of the eyebox (or exit pupil) can be adjusted. This is particularly relevant when the optical fiber is used in a display device that is placed on the user's head.
[0049] The insert and the recess can be designed to fit together in a form-fitting manner, so that the insert is aligned when inserted into the recess.
[0050] The partially reflective coating can be applied over the entire surface of at least one of the two outward-facing outer surfaces of the insert.
[0051] Furthermore, the partially reflective coating cannot be applied to the entire surface of at least one of the two outward-facing outer surfaces of the insert.
[0052] The base body and the insert can be made from the same material. Suitable materials include, for example, plastic, such as a polymer material (e.g., thiourethane, episulfide, Mitsui resin (MR-8, MR-7, MR-10, MR-174), polycarbonate (PC), polyallyldiglycol carbonate (CR-39), and polyamide), or glass (e.g., mineral glass). Patent attorneys
[0053] GEYER, FEHNERS & PARTNER
[0054] Munich - Jena
[0055] 6
[0056] The insert can be glued in such a way that the recess is filled with adhesive up to the first outer surface. In particular, the filling can be flush, so that the first outer surface is a smooth, continuous surface (especially without any steps).
[0057] If the recess is designed as a through-hole, the insert can be glued in such a way that the recess is also filled with adhesive up to the second outer surface. This can be done flush, just as described for the first outer surface.
[0058] The deflection section can have exactly two partially reflective deflection surfaces, wherein exactly two partially reflective coatings are applied to the two outward-facing outer surfaces of the insert when the partially reflective coatings are applied. In one embodiment, the two partially reflective deflection surfaces are arranged at such a distance from each other that, with respect to the light incident on the virtual image, they are located outside the shadow area of the other surface.
[0059] The optical waveguide can be provided as such (without further optical elements and / or optical coatings) or with at least one further optical element and / or at least one further optical coating.
[0060] The optical waveguide can be designed as a plane-parallel plate (at least in the section from the coupling region to the deflection region). However, it is also possible that the first outer surface and / or a second outer surface of the optical waveguide facing away from the first outer surface is curved.
[0061] The first and / or second outer surface can have a spherical curvature, an aspherical curvature, a toric curvature and / or a freeform curvature.
[0062] If only one of the two outer surfaces is curved, the other of the two outer surfaces is flat.
[0063] An optical element and / or an optical coating (each with or without optical imaging properties) may be provided on the first and / or second outer surface. These may include, for example, optical lenses for correcting refractive errors, optical elements such as cover glasses, protective films, colored substrates, etc.
[0064] A first lens can be provided, which is preferably connected to the optical waveguide with its first lens side facing the optical waveguide and which is patent attorneys
[0065] GEYER, FEHNERS & PARTNER
[0066] Munich - Jena
[0067] It has an imaging effect. This allows, for example, a lens for a display device that can be placed on a user's head. Of course, the optical fiber itself can also be designed as such a lens.
[0068] The first lens surface can be planar and / or an outer surface of the optical waveguide facing the first lens surface can be planar. In particular, the planar first lens surface and the planar outer surface of the optical waveguide can be parallel to each other.
[0069] However, it is also possible that the first lens side and / or the outside of the optical waveguide are curved.
[0070] The optical waveguide can be configured as a plane-parallel plate (at least in the section from the coupling region to the deflection region). Furthermore, the optical waveguide can be configured as a curved shell. The curvature of the outer surface facing the first lens surface can be, for example, spherical, aspherical, toric, and / or freeform. Additionally, the outer surface of the optical waveguide facing away from the first lens surface can be curved (e.g., spherical, aspherical, toric, and / or freeform). The first lens surface can have a curvature that is complementary to the curvature of the outer surface of the optical waveguide facing the first lens surface.
[0071] The first lens can be made of plastic, e.g., a polymer material (e.g., thiourethane, episulfide, Mitsui Resin (MR-8, MR-7, MR-10, MR-174), polycarbonate (PC), polyallyldiglycol carbonate (CR-39), and polyamide), or of glass (e.g., mineral glass material).
[0072] The first lens can be refractive and / or diffractive. Additionally or alternatively, the first lens can be a Fresnel lens.
[0073] It is possible that the first lens face of the first lens is in direct contact or not in direct contact with the first face of the optical waveguide facing the first lens. If there is direct contact, the refractive indices of the first lens and the optical waveguide are preferably selected such that the light coupled in via the entrance section (hereinafter also referred to as the light beam) is guided in the optical waveguide by at least one total internal reflection. If there is no direct contact, an air gap can, for example, be provided between them, which can ensure, for example, at least one total internal reflection of the light beams in the optical waveguide for guiding the light beams in the optical waveguide. A (preferably thin) layer of material can also be placed between the first lens and the optical waveguide.
[0074] GEYER, FEHNERS & PARTNER
[0075] Munich - Jena
[0076] 8 lens side and the first side of the optical waveguide are provided, wherein the refractive index of the material layer is chosen so that the desired total internal reflection of the light beams guided in the optical waveguide is ensured.
[0077] Furthermore, it is possible to provide a partially reflective and / or angle-selective layer or coating between the first lens side and the first side of the optical waveguide (at least in the areas of light guidance between the entrance section and the deflection section spaced apart from it along the predetermined direction) in order to ensure the necessary reflections for guiding the light beams.
[0078] Alternatively or additionally, surfaces forming the interfaces can have an anti-reflective coating to reduce reflections.
[0079] The surfaces of the first lens that border air can be coated with an anti-reflective coating.
[0080] The side of the first lens facing away from the optical waveguide can be coated with a hard layer or hardcoat.
[0081] The optical waveguide according to the invention can be used to provide display devices (e.g. HMDs) that can be placed on a user's head and generate an image.
[0082] The optical fiber, or a lens containing the optical fiber, can have an exit section on its back side through which the deflected light beams emerge. Furthermore, the deflecting section can redirect the light beams guided to it in the direction of the exit section so that they exit through it and are thus coupled out.
[0083] The deflection section and the exit section can be spatially separate sections. However, it is also possible for the deflection section and the exit section to coincide spatially, e.g., if the deflection section extends to the material interface.
[0084] The partially reflective deflection surfaces can each be planar. However, it is also possible for the partially reflective deflection surfaces themselves to be curved (for example, spherically or aspherically curved, or freeform).
[0085] The reflectivity of the respective partially reflective deflecting surface can, for example, be a value between 2% and less than 100%. Patent attorneys
[0086] GEYER, FEHNERS & PARTNER
[0087] Munich - Jena
[0088] 9
[0089] The optical waveguide according to the invention can in particular have a curved back side and / or a curved front side.
[0090] For guiding light within the optical waveguide, the light coupled in via the entrance section (hereinafter also referred to as the light beam) can be reflected once, twice, three times, or more. This can involve total internal reflection or reflection at a reflective coating or layer. The reflective coating or layer can be partially reflective and / or angle-selective.
[0091] A second lens can be provided, which is connected to the optical waveguide (preferably with its lens surface facing the waveguide), and which has an imaging effect. The second lens can be connected to the optical waveguide such that the waveguide is positioned between the first and second lenses. The first and second lenses can be configured as pull lenses and push lenses, respectively. The second lens can be made of plastic, e.g., a polymer material (e.g., thiourethane, episulfides, Mitsui resin (MR-8, MR-7, MR-10, MR-174), polycarbonate (PC), polyallyldiglycol carbonate (CR-39), and polyamide), or of glass (e.g., mineral glass).
[0092] It is possible that the lens surface of the second lens facing the optical waveguide is in direct contact or not in direct contact with the surface of the optical waveguide facing the second lens. If there is direct contact, the refractive indices of the second lens and the optical waveguide are preferably selected such that the light beams in the optical waveguide are guided by at least one total internal reflection. If there is no direct contact, an air gap can be provided between them, which can ensure at least one total internal reflection of the light beams in the optical waveguide.A (preferably thin) material layer can also be provided between the lens side of the second lens facing the optical waveguide and the side of the optical waveguide facing the second lens, wherein the refractive index of the material layer is chosen so that the desired total internal reflection of the light beams guided in the optical waveguide is ensured.
[0093] Furthermore, it is possible to provide a partially reflective and / or angle-selective layer or coating between the lens side of the second lens facing the optical waveguide and the side of the optical waveguide facing the second lens (at least in the light-guiding area between the entrance section and the deflection section spaced from it along the predetermined direction) in order to ensure the necessary reflections for guiding the light beams. Patent attorneys
[0094] GEYER, FEHNERS & PARTNER
[0095] Munich - Jena
[0096] 10
[0097] The first lens can have positive or negative refractive power, and the second lens can have positive or negative refractive power.
[0098] Instead of the first lens, a film or glass plate can be used, for example, for manufacturing reasons. The same applies to the second lens.
[0099] Furthermore, an optical waveguide manufactured according to one of the methods of the invention is provided, wherein the optical waveguide has an entry section and a deflection section spaced apart therefrom along a predetermined direction with two partially reflective deflection surfaces, and guides light coupled in via the entry section along the predetermined direction to the deflection section, from which it is deflected by means of the two partially reflective deflection surfaces in order to exit the optical waveguide.
[0100] The optical waveguide can have a base body with a recess extending into the base body from a first outer surface of the base body at an angle of non-zero to the predetermined direction, wherein the deflection section has an insert placed in the recess with two outwardly pointing outer surfaces on which a partially reflective coating is applied, wherein the insert is placed in the recess such that the two outwardly pointing outer surfaces on which the partially reflective coatings are applied are oriented obliquely to the predetermined direction and form the two partially reflective deflection surfaces of the deflection section.
[0101] Furthermore, a display device is provided comprising a holding device that can be placed on the user's head, an image generation module attached to the holding device which generates an image, and an optical waveguide according to the invention attached to the holding device, wherein the generated image is fed to the entry section of the optical waveguide, enters the optical waveguide via the entry section and is guided in the optical waveguide along the predetermined direction to the deflection section, from which it is deflected by means of the two partially reflective deflection surfaces in order to exit the optical waveguide, so that the user can perceive it as a virtual image in the state in which the holding device is placed on the head.
[0102] The display device can include a control unit that controls the image generation module. In particular, the control unit can control the image generation module based on supplied image data. Patent attorneys
[0103] GEYER, FEHNERS & PARTNER
[0104] Munich - Jena
[0105] 11. The image generation module and / or an image sensor unit of the image generation module may, in particular, comprise a planar image sensor, such as an LCD module, an LCoS module, an OLED module, a pLED, or a tilting mirror matrix. Each image sensor may comprise a plurality of pixels, which may be arranged, for example, in rows and columns. Each image sensor may, for example, be self-illuminating or non-self-illuminating.
[0106] Each image sensor can preferentially produce a monochromatic image, while different image sensors can produce monochromatic images with different wavelengths.
[0107] The image generation module can, for example, comprise a polychromatic image source, a combination of two or more monochromatic image sources, or a combination of a duochromatic and a monochromatic image source. Typical configurations of such image generation modules with multiple image sources include a superposition unit that combines the light beams of the multiple image sources into a single, common light beam. Such a superposition unit can be implemented, for example, as a beam splitter cube (also called an X-cube) or as a so-called rod combiner, both of which are known to those skilled in the art.
[0108] Since the deflection section should be as invisible as possible and the light reaching the viewer's eye from the surroundings should be affected as little as possible, deflection surfaces with high transmission and, consequently, low reflectivity for the light beam(s) of the monochrome or at least two-color image to be extracted are generally preferred. Typical reflectivity values are, for example, 50%, 30%, 10%, or 2%, uniformly across the visible wavelength range.
[0109] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations given, but also in other combinations or on their own, without leaving the scope of the present invention.
[0110] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings, which also disclose essential features of the invention. These exemplary embodiments serve only for illustration and are not to be interpreted as limiting. For example, a description of an exemplary embodiment with a plurality of elements or components is not to be interpreted as meaning that all of these elements or components are necessary for implementation. Rather, other exemplary embodiments may also contain alternative elements and components, fewer elements or components, or additional elements or components. Patent Attorneys
[0111] GEYER, FEHNERS & PARTNER
[0112] Munich - Jena
[0113] Twelve elements or components from different embodiments can be combined with one another unless otherwise specified. Modifications and variations described for one embodiment may also be applicable to other embodiments. To avoid repetition, identical or corresponding elements in different figures are designated with the same reference numerals and are not explained multiple times. The figures show:
[0114] Fig. 1 shows a schematic perspective view of an embodiment of the display device according to the invention;
[0115] Fig. 2 shows an enlarged partial sectional view of the first spectacle lens including a schematic representation of the first image generation module according to Fig. 1;
[0116] Fig. 3 shows an enlarged partial sectional view of a manufactured base body according to a first embodiment;
[0117] Fig. 4 shows a perspective view of an insert;
[0118] Fig. 5 shows a side view of the insert from Fig. 4 with applied semi-reflective coatings;
[0119] Fig. 6 shows an enlarged partial sectional view of a waveguide according to the invention, which is made from the base body of Fig. 3 and the insert of Fig. 5;
[0120] Fig. 7 shows an enlarged partial sectional view of a waveguide according to the invention, which is made from the base body of Fig. 3 and the insert of Fig. 5, wherein the insert is positioned laterally offset compared to the waveguide of Fig. 6;
[0121] Fig. 8 shows an enlarged partial sectional view of a waveguide according to the invention, which is made from the base body of Fig. 3 and the insert of Fig. 5, wherein the insert is positioned rotated about the x-axis compared to the waveguide of Fig. 6;
[0122] Fig. 9 shows an enlarged partial sectional view of a manufactured base body according to a further embodiment;
[0123] Fig. 10 shows an enlarged partial sectional view of a waveguide according to the invention, which is made from the base body of Fig. 9 and the insert of Fig. 5;
[0124] Fig. 11 shows an enlarged partial sectional view of a manufactured base body according to a further embodiment;
[0125] Fig. 12 shows an enlarged partial sectional view of the base body of Fig. 11 with applied semi-reflective coatings;
[0126] Fig. 13 shows an enlarged partial sectional view of a waveguide according to the invention, which is made from the base body of Fig. 12;
[0127] Fig. 14 shows an enlarged partial sectional view of a waveguide according to the invention in a further embodiment; Patent Attorneys
[0128] GEYER, FEHNERS & PARTNER
[0129] Munich - Jena
[0130] 13 Fig. 15 shows an enlarged partial sectional view of a manufactured base body according to a further embodiment;
[0131] Fig. 16 shows a perspective view of an insert;
[0132] Fig. 17 shows a side view of the insert from Fig. 16 with applied semi-reflective coatings, and
[0133] Fig. 18 shows an enlarged partial sectional view of a waveguide according to the invention, which is made from the base body of Fig. 15 and the insert of Fig. 17.
[0134] In the embodiment shown in Fig. 1, the display device 1 according to the invention comprises a holding device 2 that can be placed on the user's head, which can, for example, be designed in the manner of a conventional eyeglass frame, as well as a first and a second lens 3, 4, which are attached to the holding device 2. The first lens 3 and / or the second lens 4 can each be designed as an optical waveguide according to the invention. It is also possible that the optical waveguide according to the invention is part of the lens 3, 4. The holding device 2 with the lenses 3, 4 can, for example, be designed as sports glasses, sunglasses, and / or glasses for correcting a visual impairment, wherein a virtual image can be projected into the user's field of vision via the first lens 3, which can also be referred to as a multifunctional lens, as described below.
[0135] The display device 1 includes an image generation module 5, which can be arranged in the area of the right temple of the holding device 2, as shown schematically in Fig. 1.
[0136] The image generation module 5 can include an image sensor unit 7 for generating a first image, as schematically illustrated in Fig. 2. For this purpose, the image sensor unit 7 comprises a planar image generation element 8, to which an image sensor optic 9 is arranged. However, it is also possible that the image sensor optic 9 is not provided and can therefore be omitted. The planar image generation element 8 can, for example, comprise an OLED element, an LCD element, an LCoS element, a pLED, or a tilting mirror matrix, each comprising a plurality of pixels arranged, for example, in rows and columns. A single light beam L1 is shown schematically as a representative of the light beams emitted by the planar image generation element 8.
[0137] As can be further seen in Fig. 2, a control unit 10 with, for example, a processor P and a memory M is provided for controlling the image generation module 5. The control unit 10, which can, for example, be arranged on the holding device 2, controls the image generation module 5 and, in particular, the patent attorneys, depending on the supplied image data.
[0138] GEYER, FEHNERS & PARTNER
[0139] Munich - Jena
[0140] 14 Image-generating element 8 is positioned such that the first image is generated according to the image data. The light beams L1 emitted by image-generating element 8 pass through the image-transmitting optics 9 and then enter the first spectacle lens 3. The area of entry can also be referred to as the entry surface 12 or entry section 12.
[0141] In the embodiment described here, the first spectacle lens 3 is multi-layered and comprises an optical waveguide 13 according to the invention, which is hereinafter also referred to as channel shell 13, as well as an outer shell 24 (hereinafter also referred to as outer lens 24) and an inner shell 25 (hereinafter also referred to as inner lens 25). The channel shell 13 is the middle shell located between the outer shell 24 and the inner shell 25.
[0142] The outer lens 24 has a lens side 34 facing the channel shell 13 and a lens side 35 facing away from the channel shell 13, and the channel shell 13 has a channel side 36 facing the outer lens 24, wherein the lens side 34 is in direct contact with the channel side 36 in order to enable total internal reflection of the light beams L1 guided in the light guiding channel 21 at the channel side 36 (the refractive indices of the outer lens 24 and the channel shell 13 are chosen accordingly).Similarly, the inner lens 25 has a lens side 37 facing the channel shell 13 and a lens side 38 facing away from the channel shell 13, and the channel shell 13 has a channel side 39 facing the inner lens 25, with the lens side 37 being in direct contact with the channel side 39 to enable total internal reflection of the light beams L1 guided in the light guiding channel 21 at the channel side 39 (the refractive indices of the inner lens 25 and the channel shell 13 are chosen accordingly).
[0143] It is also possible that the lens side 34 is not in direct contact with the channel side 36. For example, an air gap can be provided between them, which ensures the desired total internal reflection of the light beams L1 guided in the light channel 21. Alternatively, a (preferably thin) material layer can be provided between the lens side 34 and the channel side 36, the refractive index of which is selected to ensure the desired total internal reflection of the light beams L1 guided in the light channel 21.
[0144] The same applies to the lens side 37 and the channel side 39, which also cannot be in direct contact with each other. Instead, for example, an air gap or a (preferably thin) layer of material can be provided between them to ensure the desired total internal reflection of the light beams L1 guided in the light-guiding channel 21. Patent attorneys
[0145] GEYER, FEHNERS & PARTNER
[0146] Munich - Jena
[0147] 15 Furthermore, it is possible to provide a partially reflective and / or angle-selective layer or coating (at least in the areas of the light guidance channel 21) between the lens side 34 and the channel side 36 and / or between the lens side 37 and the channel side 39 in order to ensure the necessary reflections of the light beams L1 guided by the light guidance channel 21.
[0148] In the embodiment described here, the channel shell 13 (or the optical waveguide 13) is designed as a plane-parallel plate, except for the area of the entrance surface 12. The inner shell 25 is designed as a lens 25 with negative refractive power, and the outer shell 24 is designed as a lens with positive refractive power. The side of the outer shell 24 facing away from the channel shell 13 forms the front 23 of the first spectacle lens 3, and the side of the inner shell 25 facing away from the channel shell 13 forms the back 11 of the first spectacle lens 3.
[0149] The front surface 23 can have a spherical curvature, an aspherical curvature, a toric curvature and / or a freeform curvature. The same applies to the back surface 11.
[0150] Due to the refractive indices of the outer and inner lenses 24, 25 and the canal shell, the light beams L1 are only reflected if their angle of incidence is 9°. Erelative to the surface perpendicular F (shown as a dashed line in Fig. 2) of a surface element where total internal reflection is to take place, greater than the corresponding critical angle 0 G This applies to total internal reflection. For angles of incidence in the range from 0° to the critical angle 0°. G The canal shell 13 is transmissive, so that the user can perceive the surroundings with his eye A through the first lens 3, as indicated by the arrow U in Fig. 2.
[0151] These transmission / reflection properties are predominantly present for radiation from the visible wavelength range.
[0152] Furthermore, the channel shell 13 has a buried deflection section 18 which includes two partially reflective deflection surfaces 19.
[0153] As already described, the light beams L1 enter the first spectacle lens 3 via the entrance surface 12. The entrance surface 12 is formed on a lateral entrance section 28 of the channel shell 13, which, in the embodiment described here, projects laterally beyond the outer and inner shells 24, 25. In addition to the entrance surface 12, the lateral entrance section 28 has a (here planar) deflecting surface 29, which deflects the light beams L1 in a first direction (here the y-direction) towards the deflecting section 18 such that the light beams L1
[0154] GEYER, FEHNERS & PARTNER
[0155] Munich - Jena
[0156] The light is directed by total internal reflection at the interfaces of the channel shell 13 to the outer and inner shells 24, 25 up to the deflection section 18. The deflection surface 29 can be, for example, reflective or partially reflective. It is also possible to design the deflection surface 29 as diffractive. In this case, the deflection surface can (but does not have to) be parallel to the channel side 36 or 39, or a part of the channel side 36 (e.g., as a reflective grating or as a reflective hologram) or of the channel side 39 (e.g., as a transmissive grating or transmissive hologram), so that the inclined side for the deflection surface 29 does not need to be provided. The channel shell 13 can, for example, be designed as a plane-parallel plate.
[0157] The deflecting section 18 then deflects the light beams L1 such that the deflected light beams L1 exit the first lens 3 via the inner lens 25 and thus via the back surface 11, creating a virtual image that the user can perceive with their eye A. The area through which the light beams L1 exit can also be referred to as the exit section 22 or exit surface 22.
[0158] Thus, in the channel shell 13 there is a light guidance channel 21 which extends along the first direction from the entry section 12 to the deflection section 18.
[0159] Since collimated light L1 with a focal plane at infinity is generally used to transport the generated image in the channel shell 13 (which can also be referred to as waveguide 13), the inner lens 25 typically has a negative refractive power to pull the focus of the virtual image towards the near range for the user (e.g., 0.5 m - 2 m). Therefore, the inner lens 25 can also be referred to as a pull lens 25. For the correction of refractive errors in highly hyperopic spectacle wearers, it may be necessary for the inner lens 25 to have a positive refractive power.
[0160] For viewing the surroundings, the influence of the pull lens 25 is compensated by the outer lens 24 with positive refractive power. Therefore, the outer lens 24 can also be referred to as a push lens 24. Optionally, the outer lens 24 can be omitted. The outer shell 24 can be omitted, for example, if the focus position of the virtual image is not adjusted. In this case, the pull lens 25 is preferably only required for refractive error correction.
[0161] In addition to adjusting the focus plane of the virtual image, the Pull lens 25 can be used for individual refractive correction for users with visual impairments.
[0162] The optical waveguide 13 can be manufactured as follows. Patent attorneys
[0163] GEYER, FEHNERS & PARTNER
[0164] Munich - Jena
[0165] 17 For example, a base body 40 (e.g., made of plastic) is produced by injection molding, comprising the inlet section 12 and a recess 41 spaced apart from it along the first direction. The recess extends from one of the channel sides 36 and 39 of the base body 40 into the base body 40 at an angle other than 0° to the first direction (Fig. 3). In the illustrated embodiment, the recess 41 extends over the entire thickness (extent in the z-direction or distance between the two channel sides 36 and 39) of the base body 40, so that the recess 41 forms a through-opening. However, it is also possible that the recess 41 does not extend over the entire thickness of the base body 40 (not shown), so that it essentially forms a blind hole in the base body 40.
[0166] Furthermore, the recess 41 extends in the z-direction and thus perpendicular to the first direction (y-direction). Alternatively, the recess can extend obliquely to the first direction (not shown).
[0167] In a further step, an insert 42 with two outwardly pointing outer surfaces 43, 44 is provided, the outer surfaces 43, 44 serving as base surfaces for the desired partially reflective deflection surfaces 19. The insert 42 is shown in perspective in Figure 4.
[0168] Partially reflective coatings 45, 46 are then applied to the two outer surfaces 43, 44, which are shown as dashed lines in the side view of the insert 42 in Fig. 5.
[0169] The insert 42 with the partially reflective coatings 45, 46 is inserted into the recess 41 and bonded with adhesive 47 to complete the optical fiber 13 (Fig. 6). Both the insert 42 and the adhesive 47 preferably have the same refractive index as the material of the base body 40, so that the two partially reflective coatings 45, 46 form the buried partially reflective deflecting surfaces 19. In Fig. 6, the boundaries of the recess 41 and the insert 42 are shown only to illustrate the manufacturing process. Optically, these are no longer visible, so they are not shown in Fig. 2. Only the optically effective partially reflective deflecting surfaces 19 are shown there.
[0170] The deflection surface 29, if a reflective coating is required, can be applied at any time. For example, the deflection surface 29 can be applied before or after the insert 42 is bonded.
[0171] As can be clearly seen in Fig. 6, the extent of the recess 41 along the first direction is significantly larger than the extent of the insert 42 along the first patent holders.
[0172] GEYER, FEHNERS & PARTNER
[0173] Munich - Jena
[0174] 18. This can be used, for example, to position the insert 42 in its position in the first direction according to user preferences. This is shown by way of example in Fig. 7. There, the insert 42 is positioned such that its distance in the first direction from the entry section 12 is greater compared to the optical fiber 13 according to Fig. 6.
[0175] As shown in Fig. 8, the inclination angle of the two semi-reflective deflecting surfaces 19 relative to the first direction can also be adjusted during bonding by rotating the insert 42, for example, about the x-axis compared to the optical fiber 13 according to Fig. 6.
[0176] Of course, the relative inclination of the two partially reflective deflecting surfaces 19 to each other always remains constant and cannot be changed, since this is determined by the two side surfaces 43 and 44.
[0177] Since the positioning of the insert 42 is adjustable in the embodiments according to Fig. 6 - 8, this type of manufacturing can also be called aligning adhesive.
[0178] Alternatively, the recess 41 and the insert 42, including the partially reflective coatings 45, 46, can also be designed to be form-fitting relative to each other, or so that the insert 42 can be inserted into the recess 41 and is guided by the recess 41 during insertion. Naturally, sufficient clearance is provided to ensure that the partially reflective coatings 45, 46 are not damaged during insertion, and preferably, a full-surface bond with the walls of the recess in the area of the partially reflective coatings 45, 46 is possible. Figure 9 shows a provided base body 40 with such a recess 41. In Figure 10, the insert 42 is inserted and bonded, thus completing the optical fiber 13.
[0179] In the embodiments described so far, the partially reflective coatings 45, 46 are applied to the side surfaces 43, 44 of the insert 42. However, it is also possible to design the recess 41 such that it extends obliquely into the base body 40 from one of the channel sides 36 and 39 in the first direction and has two mutually facing inner surfaces 48, 49, each extending obliquely in the predetermined direction (Fig. 11).
[0180] Partially reflective coatings 50, 51 are then applied to the inner surfaces 48, 49, as shown in Fig. 12. Patent attorneys
[0181] GEYER, FEHNERS & PARTNER
[0182] Munich - Jena
[0183] 19 The recess 41 can then be filled with the adhesive 47 index-matched to the material of the base body 40 to complete the optical waveguide 13, as shown in Fig. 12.
[0184] A combination of these two described alternatives (Figures 4-10 on the one hand and Figures 11-13 on the other) is also possible. For this, after providing the base body 40 according to Figures 11 and 12, only an insert according to Figure 5 needs to be provided and glued into the recess 41, resulting in an optical fiber 13 according to Figure 14.
[0185] This then has four partial Iref lective deflection surfaces 19.
[0186] In a modification of this embodiment according to Figure 14, a partially reflective coating 45, 46 and a partially reflective coating 50, 51 can be omitted, so that the waveguide 13 then has exactly two partially reflective coatings (a partially reflective coating on one of the two outer surfaces 43, 44 of the insert 42 and a partially reflective coating on one of the two inner surfaces 48, 49). Furthermore, it is possible that the optical waveguide 13 has exactly three partially reflective coatings, for which one partially reflective coating on one of the two outer surfaces 43, 44 of the insert 42 and two partially reflective coatings on the two inner surfaces 48, 49 or two partially reflective coatings on the two outer surfaces 43, 44 of the insert 42 and one partially reflective coating on one of the two inner surfaces 48, 49 is omitted in comparison to the optical waveguide 13 shown in Fig. 14.
[0187] The optical waveguide 13 described so far (in particular the optical waveguide 13 shown in Figures 6, 7, 8, 10, 13 and 14) can be used as such (without an outer lens and without an inner lens).
[0188] Figures 15 to 18 show the fabrication of an optical waveguide 13 in the same manner as Figures 3 to 6, wherein the two channel faces 36 and 39 in the finished optical waveguide 13 are curved and can, for example, form the front and back faces 23 and 11. The optical waveguide 13 produced in this way can be used as such (preferably without an outer and / or inner lens) and, for example, as a spectacle lens 3.
[0189] The front face 23 of the optical waveguide 13 can have a spherical curvature, an aspherical curvature, a toric curvature and / or a freeform curvature. The same applies to the back face 11 of the optical waveguide 13.
[0190] The index-adjusted adhesive 47 is understood to be, in particular, an adhesive whose refractive index at a wavelength of 550 nm differs by no more than 0.1 from the refractive index of patent attorneys.
[0191] GEYER, FEHNERS & PARTNER
[0192] Munich - Jena
[0193] 20 (preferably less than 0.01 and most preferably less than 0.001) of the material of the base body 40 at the wavelength of 550 nm.
[0194] In the display device 1 according to the invention, the virtual image is projected into the user's field of vision via the first lens 3. Projection via the second lens 4 is also possible. Furthermore, the display device 1 can be designed such that information or virtual images are projected via both lenses 3 and 4. The projection can be arranged to create a three-dimensional image impression. However, this is not mandatory.
[0195] The lenses 3, 4 can have a refractive power of zero or a non-zero refractive power (particularly for correcting a refractive error). In particular, both the front surface 23 and the back surface 11 can be curved. The front surface 23 is specifically spherically curved. However, the front surface 23 can generally be spherically, aspherically, toricly, and / or freeformly curved. If the lens 3, 4 has a non-zero refractive power to correct a refractive error, the curvature of the back surface 11 is usually chosen accordingly to achieve the corresponding correction. The back surface 11 can have a curvature other than spherical (including a shape that provides a progressive or multifocal lens effect). In general, the back surface can be spherically, aspherically, toricly, and / or freeformly curved.Of course, it is also possible that the curvature of the back together with the curvature of the front 23 achieves the desired correction of refractive error.
[0196] The holding device 2 need not be designed as a spectacle-like holding device. Any other type of holding device is also possible, with which the display device 1 can be placed on and worn on the head.
Claims
patent attorneys GEYER, FEHNERS & PARTNER Munich - Jena 21 tooz technologies GmbH Attorney's file: PAT 4377 / 072-PCT Patent claims 1. Method for manufacturing an optical waveguide (13) comprising an entrance section (12) and a deflection section (18) spaced apart from it along a predetermined direction, with two partially reflective deflection surfaces (19), and which guides light (L1) coupled in via the entrance section (12) along the predetermined direction to the deflection section (18), from which it is deflected by means of the two partially reflective deflection surfaces (19) to exit the optical waveguide (13), the procedure comprises the following steps: Providing a base body (40) with the entry section (12) and a recess (41) spaced apart from it along the predetermined direction, which extends from a first outer surface (36; 39) of the base body (40) into the base body (40) at an angle of non-0° to the predetermined direction, Providing an insert (42) with two outwardly facing surfaces (43, 44), Applying a partially reflective coating (45, 46) to each of the two outward-facing outer surfaces (43, 44) of the insert (42), Inserting the insert (42) into the recess (41) and bonding the insert (42) in the recess (41) such that the two outwardly pointing outer surfaces (43, 44) on which the semi-reflective coatings (45, 46) are applied are oriented obliquely to the predetermined direction and form the two semi-reflective deflection surfaces (19) of the deflection section (18).
2. Method according to claim 1, wherein the base body (40) is provided such that the recess (41) extends completely through the base body (40) as a through-hole.
3. Method according to claim 1 or 2, wherein the base body (40) is manufactured by injection molding.
4. Method according to one of the above claims, wherein the insert (42) is held in the desired orientation during bonding. patent attorneys GEYER, FEHNERS & PARTNER Munich - Jena 22 5. Method according to one of the above claims, wherein the positioning of the insert (42) in the recess (41) during bonding is adjusted as a function of a target value of a predetermined characteristic.
6. Method according to one of the above claims, wherein the extent of the recess (41) in the predetermined direction is at least 10% greater than the distance between the two outer surfaces (43, 44) of the insert (42), so that the position of the insert (42) along the predetermined direction and / or the orientation of the insert (42) in which the insert (42) is bonded is adjustable.
7. Method according to any one of claims 1 to 5, wherein the insert (42) and the recess (41) are designed to fit together in a form-fitting manner, such that the insert (42) is thereby aligned when inserted into the recess (41).
8. Method according to one of the above claims, wherein the partially reflective coating (45, 46) is applied over the entire surface of at least one of the two outwardly pointing outer surfaces (43, 44) of the insert (42).
9. Method according to one of the above claims, wherein the partially reflective coating (45, 46) is not applied over the entire surface of at least one of the two outwardly pointing outer surfaces (43, 44) of the insert (42).
10. Method according to one of the above claims, wherein the base body (40) and the insert (42) are made of the same material.
11. Method according to one of the above claims, wherein the insert (42) is glued in such a way that the recess (41) is filled with adhesive (47) up to the first outer surface (36; 39).
12. Method according to one of the above claims, wherein the deflection section (18) has exactly two partially reflective deflection surfaces (19), wherein when applying the partially reflective coating (45, 46) to the two outwardly pointing outer surfaces (43, 44) of the insert (42) exactly two partially reflective coatings (45, 46) are applied.
13. Optical waveguide manufactured according to any of the above claims, wherein the optical waveguide (13) has an entry section (12) and a deflection section (18) spaced apart from it along a predetermined direction with two partially reflective patent attorneys GEYER, FEHNERS & PARTNER Munich - Jena 23 deflection surfaces (19) and guides light (L1) coupled in via the inlet section (12) along the predetermined direction to the deflection section (18), from which it is deflected by means of the two partially reflective deflection surfaces (19) to exit the optical waveguide (13), wherein the optical waveguide (13) has a base body (40) with a recess (41) extending from a first outer surface (36; 39) of the base body (40) into the base body (40) at an angle of non-0° to the predetermined direction, wherein the deflection section (19) has an insert (42) inserted into the recess (41) with two outwardly pointing outer surfaces (43, 44) on which a partially reflective coating (45, 46) is applied, wherein the insert (42) is inserted into the recess (41) such that the two outwardly pointing outer surfaces (43, 44) on which the partially reflective coatings (45, 46) are applied are oriented obliquely to the predetermined direction and form the two partially reflective deflecting surfaces (19) of the deflecting section (18).
14. Display device with a holding device (2) that can be placed on the head of a user, an image generation module (5) attached to the holding device (2), which generates an image, and an optical waveguide (13) attached to the holding device (2) according to claim 13, wherein the generated image is supplied to the entry section (12) of the optical waveguide (13), enters the optical waveguide (13) via the entry section (12) and is guided in the optical waveguide (13) along the predetermined direction to the deflection section (18), from which it is deflected by means of the two partially reflective deflection surfaces (19) in order to exit the optical waveguide (13), so that the user can perceive it as a virtual image when the holding device (2) is placed on the head.
15. Method for manufacturing an optical waveguide comprising an entrance section (12) and a deflection section (18) spaced apart from it along a predetermined direction, with two partially reflective deflection surfaces (19), and which guides light (L1) coupled in via the entrance section (12) along the predetermined direction to the deflection section (18), from which it is deflected by means of the two partially reflective deflection surfaces (19) to exit the optical waveguide (13), the procedure comprises the following steps: Providing a base body (40) with the entry section (12) and a recess (41) spaced apart from it along the predetermined direction, which extends from a first outer surface (36; 39) of the base body (40) obliquely into the base body (40) in the predetermined direction and which has two mutually facing inner surfaces (48, 49) which each extend obliquely in the predetermined direction, patent attorneys GEYER, FEHNERS & PARTNER Munich - Jena 24 Applying a partially reflective coating (50, 51 ) to the two facing inner surfaces (48, 49) to form the two partially reflective deflecting surfaces (19) of the deflecting section (18), - Filling the recess (41) with an insert (42) and / or an adhesive (47).
16. Method for manufacturing an optical waveguide comprising an entrance section (12) and a deflection section (18) spaced apart from it along a predetermined direction, with at least two partially reflective deflection surfaces (19), and which guides light (L1) coupled in via the entrance section (12) along the predetermined direction to the deflection section (18), from which it is deflected by means of the at least two partially reflective deflection surfaces (19) to exit the optical waveguide (13), the procedure comprises the following steps: Providing a base body (40) with the entry section (12) and a recess (41) spaced apart therefrom along the predetermined direction, which extends obliquely into the base body (40) from a first outer surface (36; 39) of the base body (40) in the predetermined direction and which has two mutually facing inner surfaces (48, 49), at least one of which extends obliquely in the predetermined direction, providing an insert (42) with two mutually pointing outer surfaces (43, 44), Applying a partially reflective coating (45, 46, 50, 51) to at least two surfaces from a group comprising the two outer surfaces (43, 44) and the two inner surfaces (48, 49), Inserting the insert (42) into the recess (41) and bonding the insert (42) in the recess such that the at least two surfaces on which the partially reflective coating (45, 46, 50, 51) is applied are oriented obliquely to the predetermined direction and form the at least two partially reflective deflection surfaces (19).