Method for determining a value of a parameter of an optical system

Abstract

The optical system includes a front optical element, a rear optical element, and a waveguide. The rear optical element is designed to be positioned closer to the wearer's eye than the front optical element. The waveguide is located between the front and rear optical elements. The waveguide has an exit surface arranged to output an image to the wearer. The method includes determining, based on a predicted focal map of the optical system, the values ​​of parameters of a first portion of the front optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of a second portion of the front optical element corresponding to the distance vision portion of the optical system.

Description

Technical Field

[0001] This disclosure relates to methods for determining the values ​​of parameters for an optical system. More specifically, the optical system may be specifically designed for use in augmented reality eye-wearing devices. Background Technology

[0002] Augmented reality glasses require specific optical systems. These optical systems may need to provide two types of vision: • Perspective vision, which allows the wearer to see their surroundings. • Supplemental image vision, which allows the wearer to see supplemental images.

[0003] Typically, a waveguide encapsulated between two optical elements is used to display a supplementary image.

[0004] The values ​​of the parameters for these optical systems must be carefully selected, more precisely, the values ​​of the parameters for the two optical elements that encapsulate the waveguide.

[0005] A method is needed to determine the values ​​of the parameters of these optical systems. Summary of the Invention

[0006] A simplified overview is provided below to offer a basic understanding of the different aspects of this disclosure. This overview is not a comprehensive summary of all anticipated aspects and is neither intended to identify key or essential elements of all aspects nor to depict the scope of any or all aspects. The sole purpose is to present some ideas of one or more aspects in a simplified form as a prelude to the more detailed descriptions that follow.

[0007] One aspect of this disclosure is a method for determining the values ​​of parameters of an optical system. The optical system includes a front optical element, a rear optical element, and a waveguide. The rear optical element is designed to be positioned closer to the wearer's eye than the front optical element. The waveguide is located between the front and rear optical elements. The waveguide has an exit surface arranged to output an image to the wearer. The method includes: determining the values ​​of parameters of a first portion of the front optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of a second portion of the front optical element corresponding to the distance vision portion of the optical system based on a projected focal map of the optical system. The method further includes: determining the values ​​of parameters of the first portion of the rear optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of the second portion of the rear optical element corresponding to the distance vision portion of the optical system based on a projected focal map of the optical system, such that the rear optical element is a fade-out type.

[0008] Another aspect of this disclosure is an optical system. The optical system includes a front optical element, a rear optical element, and a waveguide. The rear optical element is designed to be positioned closer to the wearer's eye than the front optical element. The waveguide is located between the front and rear optical elements. The waveguide has an exit surface arranged to output an image to the wearer. The values ​​of parameters of a first portion of the front optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of a second portion of the front optical element corresponding to the far vision portion of the optical system are determined based on the expected focal length map of the optical system. The values ​​of parameters of the first portion of the rear optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of the second portion of the rear optical element corresponding to the far vision portion of the optical system are determined based on the expected focal length map of the optical system, and the rear optical element is a stepped-back type.

[0009] Another aspect of this disclosure is an eye-wearing device. The eye-wearing device includes an optical system. The optical system includes a front optical element, a rear optical element, and a waveguide. The rear optical element is designed to be positioned closer to the wearer's eye than the front optical element. The waveguide is located between the front and rear optical elements. The waveguide has an exit surface arranged to output an image to the wearer. The values ​​of parameters of a first portion of the front optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of a second portion of the front optical element corresponding to the far vision portion of the optical system are determined based on the expected focal length map of the optical system. The values ​​of parameters of the first portion of the rear optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of the second portion of the rear optical element corresponding to the far vision portion of the optical system are determined based on the expected focal length map of the optical system, and the rear optical element is a receding type.

[0010] Another aspect of this disclosure is a computer-implemented method for determining the values ​​of parameters of an optical system. The optical system includes a front optical element, a rear optical element, and a waveguide. The rear optical element is designed to be positioned closer to the wearer's eye than the front optical element. The waveguide is located between the front and rear optical elements. The waveguide has an exit surface arranged to output an image to the wearer. The method includes: determining the values ​​of parameters of a first portion of the front optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of a second portion of the front optical element corresponding to the distance vision portion of the optical system based on a projected focal map of the optical system. The method further includes: determining the values ​​of parameters of the first portion of the rear optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of the second portion of the rear optical element corresponding to the distance vision portion of the optical system based on a projected focal map of the optical system, such that the rear optical element is a fade-out type.

[0011] Another aspect of this disclosure is a computer program comprising instructions that, when executed by a computer, cause the computer to perform a method for determining values ​​of parameters of an optical system. The optical system includes a front optics element, a rear optics element, and a waveguide. The rear optics element is designed to be positioned closer to the wearer's eye than the front optics element. The waveguide is located between the front and rear optics elements. The waveguide has an exit surface arranged to output an image to the wearer. The method includes: determining, based on a projected focal map of the optical system, the values ​​of parameters of a first portion of the front optics element corresponding to the near vision portion of the optical system and the values ​​of parameters of a second portion of the front optics element corresponding to the distance vision portion of the optical system. The method further includes: determining, based on a projected focal map of the optical system, the values ​​of parameters of the first portion of the rear optics element corresponding to the near vision portion of the optical system and the values ​​of parameters of the second portion of the rear optics element corresponding to the distance vision portion of the optical system, and causing the rear optics element to be a fade-out type.

[0012] A computer may include memory and a processor. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system-on-a-chip (SoCs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuitry, and other suitable hardware configured to perform the various functions described throughout this disclosure. Memory may be a computer-readable medium. By way of example and not limitation, such a computer-readable medium may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disc storage devices, magnetic disk storage devices, other magnetic storage devices, combinations of computer-readable media of the types described above, or any other medium that may be used to store computer-executable code in the form of instructions or data structures accessible to the computer's processor.

[0013] Another aspect of this disclosure is a computer-readable, non-transitory program storage device that tangibly implements a program executable by the computer to perform instructions for a method of determining values ​​of parameters of an optical system. The optical system includes a front optical element, a rear optical element, and a waveguide. The rear optical element is designed to be positioned closer to the wearer's eye than the front optical element. The waveguide is located between the front and rear optical elements. The waveguide has an exit surface arranged to output an image to the wearer. The method includes: determining, based on a projected focal map of the optical system, the values ​​of parameters of a first portion of the front optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of a second portion of the front optical element corresponding to the distance vision portion of the optical system. The method further includes: determining, based on the projected focal map of the optical system, the values ​​of parameters of the first portion of the rear optical element corresponding to the near vision portion of the optical system and the values ​​of parameters of the second portion of the rear optical element corresponding to the distance vision portion of the optical system, such that the rear optical element is a fade-out type. Attached Figure Description

[0014] To gain a more complete understanding of the descriptions and advantages presented herein, reference is now made to the following brief description in conjunction with the accompanying drawings and detailed description, wherein the same reference numerals denote the same parts.

[0015] Figures 1a and 1b show the optical system.

[0016] Figure 2 It refers to eyeglasses.

[0017] Figure 3 This describes a first embodiment of a method for determining the values ​​of parameters of an optical system.

[0018] Figure 4 The curves show the progressive distribution of the optical element 13 under different formulations and light values.

[0019] Figure 5 This describes a second embodiment of a method for determining the values ​​of parameters of an optical system.

[0020] Figures 6 to 9 The focal length diagrams are shown for different examples, representing the rear optics, the front optics, and combinations of the rear and front optics. Detailed Implementation

[0021] The detailed description set forth below with reference to the accompanying drawings is intended as a description of various possible embodiments and not as an indication of only embodiments in which the concepts described herein can be implemented. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be implemented without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring these concepts. Optical system

[0022] Figures 1a and 1b illustrate an optical system 10 that simultaneously provides perspective vision (TV) and supplementary vision (SV) by outputting a supplementary image (SI) to the wearer's eye 100. The optical system 10 is capable of correcting the wearer's perspective vision (TV). The optical system 10 includes a rear optical element 12 and a front optical element 13, wherein the rear optical element 12 is positioned as close as possible to the wearer's eye when the optical system 10 is worn. The optical system 10 also includes a waveguide 2 arranged to output the supplementary image (SI) to the wearer through its exit surface (ES).

[0023] As shown in Figures 1a and 1b, waveguide 2 is located between the rear optical element 12 and the front optical element 13. Here, the term "between" indicates that several points on a portion of waveguide 2 are each aligned with corresponding points on both the rear optical element 12 and the front optical element 13. In addition, when the optical system (10) is worn, these aligned points are also aligned with points on the wearer's eye (e.g., points on the retina).

[0024] Perspective-based visual television (TV) refers to the vision a wearer experiences when viewing their surroundings. It is also known as ophthalmic vision (OV).

[0025] As shown in Figures 1a and 1b, the front optical element 13 and the rear optical element 12 can be a single integrated structure. In this case, the waveguide 2 is enclosed within this single integrated structure. In this case, the term "front portion" can be used to refer to the front optical element 13, and the term "rear portion" can be used to refer to the rear optical element 12.

[0026] The front optical element 13 and the rear optical element 12 can each be an ophthalmic lens. In this case, an air gap can exist between the front optical element 13 and the waveguide 2, and between the rear optical element 12 and the waveguide 2.

[0027] In the first part, the front optical element 13 and the rear optical element 12 can be made of the same transparent refractive material or different transparent refractive materials.

[0028] The emission surface can face the wearer's eyes.

[0029] Waveguide 2 can be an embedded waveguide optical element.

[0030] According to the embodiments of Figures 1-a and 1-b, the proximal surface PS and the distal surface DS are parallel surfaces.

[0031] According to another embodiment, the proximal surface PS and the distal surface DS are non-parallel surfaces.

[0032] According to the embodiments of Figures 1a and 1b, the proximal surface PS and / or the distal surface DS are planar surfaces.

[0033] According to another embodiment, the proximal surface PS and / or the distal surface DS are curved surfaces; such curved surfaces are, for example, spherical, complex, or spherical complex; such curved surfaces may also be despheroidized spherical or complex or spherical complex.

[0034] Waveguide 2 is made of a transparent refractive material. The refractive index of the transparent refractive material constituting waveguide 2 may be the same as, slightly different from, or significantly different from the refractive index of the transparent refractive material constituting the subsequent optical element 12 or the refractive index of the transparent refractive material constituting the preceding optical element 13.

[0035] According to the embodiments in Figures 1a and 1b, the proximal surface PS and the distal surface DS of waveguide 2 are parallel surfaces. The proximal surface PS of waveguide 2 is the surface of waveguide 2 closest to the wearer's eye when the wearer is wearing the optical system 10.

[0036] According to another embodiment, the proximal surface PS and the distal surface DS are non-parallel surfaces.

[0037] According to the embodiments of Figures 1a and 1b, the proximal surface PS and / or the distal surface DS are planar surfaces.

[0038] According to another embodiment, the proximal surface PS and / or the distal surface DS are curved surfaces; such curved surfaces are, for example, spherical, complex, or spherical complex; such curved surfaces may also be despheroidized spherical or complex or spherical complex.

[0039] When the rear optical element 12 and the front optical element 13 are a single integrated structure, this integrated structure has a front surface FS and a rear surface BS. The rear surface BS is the surface of the integrated structure closest to the wearer's eye when the optical system 10 is worn. The front surface FS may be convex, and the rear surface BS may be concave. The optical power of the optical system 10 for see-through vision (TV) depends on the corresponding curvatures of the surfaces FS and BS, as well as the refractive index of the material of the optical system 10.

[0040] When the rear optical element 12 is a posterior ophthalmic lens and the front optical element 13 is an anterior ophthalmic lens, each of the posterior and anterior ophthalmic lenses has an anterior surface and a posterior surface. The optical power of the optical system 10 for ophthalmic vision (OV) depends on the corresponding curvatures of the posterior and anterior surfaces of the posterior and anterior ophthalmic lenses, as well as their corresponding refractive indices.

[0041] Waveguide 2 is configured to introduce supplementary light from a source not shown in detail in order to produce a supplementary image SI. The structure of waveguide 2 is not the subject of this specification, and reference can be made to other available literature on this subject. An example of a suitable waveguide is described in PCT applications WO 2005024491 or WO 200195027 under the name of LUMUS Corporation.

[0042] The supplementary image SI may be distorted due to the optical characteristics of the optical system 10. When the optical system 10 is a monolithic structure and the exit surface of the waveguide 2 is planar, or when the refractive index of the material of the monolithic structure is equal to the refractive index of the material of the waveguide 2, the distortion depends on the curvature of the rear surface BS of the monolithic structure and the refractive index of the material of the monolithic structure. When the optical system 10 is composed of an anterior ophthalmic lens and a posterior ophthalmic lens, the distortion depends on the curvature of the rear surface of the posterior ophthalmic lens, the curvature of the anterior surface of the posterior ophthalmic lens, and the refractive index of the material of the posterior ophthalmic lens.

[0043] Waveguide 2 is laterally defined within a region of optical system 10 in certain directions generally parallel to the front surface FS and the rear surface BS. In this configuration, the front portion 13 and the rear portion 12 of optical system 10 extend beyond the peripheral edge 2e of waveguide 2. Thus, optical system 10 has an intermediate portion 11 that extends beyond the edge 2e of waveguide 2 and continuously connects portions 13 and 12 to the peripheral edge E of optical system 10.

[0044] Waveguide 2 can be virtually divided into two regions, 2a and 2b, separated by a virtual edge 2e'. Region 2a is the imaging part, from which the supplementary image SI originates, depending on the wearer's eye; region 2b is the propagation part, within which the supplementary image propagates from source 3 without being presented to the wearer.

[0045] The edge of region 2a is the outline of the supplementary image SI output by waveguide 2. The supplementary image SI intersects the near-side surface PS according to the exit surface ES. The surface on the far-side surface corresponding to the exit surface ES is called the "opposite surface" OS. According to this example, the imaging portion is an approximate rectangle with a width of W and a height of H.

[0046] According to a commonly used optical reference frame, the exit surface ES is defined by an aperture angular profile denoted as AC(α, β), where α is the eye depression angle, β is the eye azimuth angle, and the poles of α and β are the rotation center CRE of the wearer's eye 100 located behind the lens. 101 corresponds to the axis where α = β = 0.

[0047] According to the example, the aperture AC can be + / - 15° (degrees) on either side of the optical axis of the complementary vision, which passes through the center of the exit surface ES. The aperture is defined in the azimuth plane by |β1| + |β2|. The aperture is defined in the vertical plane by |α1| + |α2|. The generatrix of the aperture angular profile boundary intersects the rear surface BS of the lens in the region where the perspective and complementary visions overlap. In the configurations of Figures 1a and 1b, the corresponding optical axes of the perspective and complementary visions are the same, but they can be different.

[0048] Figures 1a and 1b show the optical system 10 in the position used by the wearer. Therefore, the wearer's eye is positioned behind the optical system 10 on the side of the rear surface, such that the eye receives light corresponding to the perspective vision TV and originating from the environment in front of the lens, and also receives light corresponding to the supplementary image SI introduced by the waveguide 2. The beams of the two types of light, TV and SV, correspond to the perspective vision TV and the supplementary vision SV, respectively. After passing through the pupil 120, the two types of light form the perspective image and the supplementary image on the wearer's retina 110. Reference numeral 130 indicates the iris surrounding the wearer's pupil 120. The direction the wearer is looking corresponds to the optical axis of the eye 100. This optical axis intersects the surfaces FS and BS of the optical system 10 at corresponding points, which change as the eye 100 moves within the wearer's eye socket.

[0049] The optical system 10 can be integrated into eyewear.

[0050] Eyewear encompasses any type of head-mounted device of any suitable shape factor designed to be worn in or in front of at least one of the wearer's eyes.

[0051] Eye-wearing devices include head-mounted display devices (e.g., near-eye display devices, augmented reality devices, virtual reality devices, or mixed reality devices), helmets (with face shields), glasses, goggles, masks, face shields, contact lenses, and intraocular implants.

[0052] The glasses can be placed on the wearer's nose and ears. Figure 2This illustrates an embodiment of eyeglasses EY. Eyeglasses EY may include two lenses L1 and L2 and a frame F. One or both lenses L1 and L2 may be the previously presented optical system 10. The frame F may include two temples or armrests A1 and A2 and a front portion F1. The front portion F1 may include a right lens ring R1 and a left lens ring R2 connected together via a bridge B. The front portion F1 and the two temples A1 and A2 may be connected using two hinges H1 and H2. Hinges H1 and H2 allow the temples A1 and A2 to fold along the front portion F1. The lens rings R1 and R2 of the frame F1 may be configured to receive and hold lenses L1 and L2.

[0053] The focal power of the rear optical element 12, the front optical element 13, and the optical system 10 can depend on the portion of the element being considered. Each of these elements may, for example, have a distance viewing portion, an intermediate viewing portion, and a near viewing portion, all of which have different focal powers.

[0054] The distance vision portion is designed for use by the wearer during distance vision activities. The near vision portion is designed for use by the wearer during near vision activities. The intermediate vision portion is designed for use by the wearer during intermediate vision activities. In other words, the distance vision portion of the element is the part through which the wearer's gaze axis passes when the wearer is engaged in distance vision activities. The near vision portion of the element is the part through which the wearer's gaze axis passes when the wearer is engaged in near vision activities. The intermediate vision portion of the element is the part through which the wearer's gaze axis passes when the wearer is engaged in intermediate vision activities.

[0055] To determine the near and distance vision portions of an optical element (e.g., an ophthalmic lens), a prescription associated with the optical element and a focal length map of the optical element obtained using a lens mapper can be used. Using the focal length map, the distance vision portion can be determined by finding the portion of the optical element whose focal power lies between the mean spherical power of the distance vision and the mean spherical power of the distance vision plus 15% of the prescription refraction. Using the focal length map, the near vision portion can be determined by finding the portion of the optical element whose focal power lies between the mean spherical power of the distance vision plus 85% of the prescription refraction and the mean spherical power of the distance vision plus 100% of the prescription refraction. Typically, the intermediate vision portion lies between the distance and near vision portions, for example, equidistant from both.

[0056] Distant viewing activity is the activity of viewing objects without needing to adjust; theoretically, it refers to objects at infinity, but it is generally considered that objects at a distance greater than 3 meters are viewed using distant viewing. Near viewing activity is the activity of viewing objects at close range, typically less than 0.5 meters, such as when reading a book. Intermediate viewing activity is the activity of viewing objects located between 0.5 meters and 5 meters away.

[0057] During supplemental vision (SV), the focal length of the optical system 10 is determined by considering only the focal length of the rear optical element 12. During perspective vision (TV), the focal length of the optical system 10 is determined by considering both the focal length of the rear optical element 12 and the focal length of the front optical element 13.

[0058] When considering the near-vision power of the optical system 10, the near-vision power of the rear optical element 12 and possibly the near-vision power of the front optical element 13 are also considered.

[0059] When considering the focal length of the central portion of the optical system 10, the focal length of the central portion of the rear optical element 12 and possibly the focal length of the central portion of the front optical element 13 are also considered.

[0060] When considering the focal length of the distance-viewing portion of the optical system 10, the focal length of the distance-viewing portion of the rear optical element 12 and possibly the focal length of the distance-viewing portion of the front optical element 13 are also considered.

[0061] A prescription typically includes a focal power specifically for distance vision and a downlight specifically for near vision. The focal power of the distance vision portion of an optical element conforming to the prescription (e.g., optical system 10) can be obtained directly from the distance vision portion of the prescription. The near vision focal power of the optical element conforming to the prescription can be obtained by adding the downlight of the prescription to the focal power of the distance vision portion of the prescription.

[0062] Typically, when worn by a standing wearer, the near vision portion of the optical element is located below the far vision portion, and the intermediate vision portion is located between the near vision portion and the far vision portion, for example, equidistant from the near vision portion and the far vision portion. Methods for determining the values ​​of parameters of an optical system

[0063] Figure 3 This describes a first embodiment of a method for determining the values ​​of parameters of an optical system 10. Figure 3 The method can be, for example, a computer-implemented method.

[0064] Figure 3 The method can be implemented in a computer that includes memory and a processor.

[0065] Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system-on-a-chip (SoCs), baseband processors, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure.

[0066] The memory may be a computer-readable medium. By way of example and not limitation, such a computer-readable medium may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disc storage devices, magnetic disk storage devices, other magnetic storage devices, combinations of computer-readable media of the types described above, or any other medium that may be used to store computer-executable code in the form of instructions or data structures accessible to a computer's processor.

[0067] like Figure 3 As presented in the first embodiment, the method for determining the values ​​of the parameters of the optical system 10 may include: - Step 301: Selecting front optical element 13 from a group of up to 6 pre-defined front optical elements. - Step 302: Determine the values ​​of the parameters of the rear optical element 12 based on the expected focal length map of the optical system 10 and the selected front optical element.

[0068] Figure 3 The advantage of this method is that the front optics 13 used can be selected from a limited number of types and can be produced cost-effectively using mass production techniques. The rear optics 12 can be specific to each wearer and can be custom-made. If the front optics 13 is generic for all prescriptions and located in a fixed position in the frame (regardless of the wearer's fitting position), then the front optics 13 may potentially introduce prismatic effects or aberrations under see-through vision (TV). The rear optics 12 can be optimized to eliminate or minimize these prismatic effects or aberrations, taking into account the wearer's actual half-pupil distance and fitting height.

[0069] In other words, use Figure 3 The method utilizes a mass-producible front optic 13 derived from a limited set of front optics with different downlighting and a finite power (between 0 and 2 diopters). The power of the front optic 13 must not exceed a certain level. In practice, a high power in the front optic 13 implies a high absolute negative power in the rear optic, thus requiring the wearer to adjust to focus on the supplementary image. The rear optic 12 can advantageously be a personalized lens (e.g., a freeform type) with power variations within a limited range. The rear optic 12 will affect how the supplementary image is seen. The combination of the front and rear optics 13 will affect the perspective vision (TV).

[0070] In an embodiment, step 301 of selecting the front optical element 13 can also be implemented based on the wearer's half pupillary distance.

[0071] In an embodiment, step 301 of selecting the front optical element 13 can also be implemented based on the wearer's fitting height.

[0072] The parameters of the rear optical element 12, which can be optimized using one of the methods described below, can be optical power, astigmatism, and optical distortion. The values ​​of these parameters can depend on the portion of the rear optical element 12 that is being considered. For example, the black optical element 12 may include a distance-viewing portion and a near-viewing portion, and the values ​​of the parameters may differ depending on which of these two portions is being considered.

[0073] In other embodiments, the parameters of the rear optical element 12 may include: • The refractive index of the material of the optical element 12 after formation, • The shape of the rear surface of the rear optical element 12, and • The shape of the front surface of the rear optical element 12.

[0074] When waveguide 2 is not flat, the method can also use the values ​​of the parameters of waveguide 2 (e.g., parameters representing the curvature of the back surface of waveguide 2 or the reflectivity of the material of waveguide 2) to determine the values ​​of the parameters of the back optical element 12.

[0075] The pre-defined front optical elements can all have a focal power of less than 1.5 diopters, for example less than 1 diopter, in the distance vision portion.

[0076] In an embodiment, waveguide 2 can be configured such that the supplementary image portion is displayed in the far-view portion of the optical system 10 and partially displayed in the near-view portion of the optical system 10.

[0077] In an embodiment, when the focal power of the distance-viewing portion of the first pre-established front optical element from the pre-established group of front optical elements is higher than the focal power of the distance-viewing portion of the second pre-established front optical element from the pre-established group of front optical elements, then the focal power of the near-viewing portion of the first pre-established front optical element is lower than the focal power of the near-viewing portion of the second pre-established front optical element.

[0078] Different methods can be used to determine the pre-established group of front optical elements. Figure 4 This represents the progressive distribution curve of the front optics 13 under different prescriptions and applied light values. The horizontal axis corresponds to the vertical position (in mm) along the horizontal centerline of the front optics 13. The origin corresponds to the prism reference point. When this position is negative, it means that the position is below the horizontal centerline, and therefore within the portion of the front optics 13 dedicated to near vision. The vertical axis corresponds to the focal power at a given position. The pre-defined front optics can be divided into two groups of three.

[0079] The first group may include: • An optical element having a distance vision portion with a power between 0.25 and 0.75 diopters, for example, 0.5 diopters, and a near vision portion with a power between 1.5 and 2 diopters, for example, 1.75 diopters. • An optical element having a distance vision portion with a power between 0.0 and 0.5 diopters, for example, 0.0 diopters, and a near vision portion with a power between 2.5 and 3 diopters, for example, 2.75 diopters. • An optical element having a distance vision portion with a power between 0.0 and 0.5 diopters, for example, 0.0 diopters, and a near vision portion with a power between 3.25 and 3.75 diopters, for example, 3.5 diopters. The second group may include: • An optical element having a distance vision portion with a power between 0.25 and 0.75 diopters, for example, 0.5 diopters, and an intermediate vision portion with a power between 0.75 and 1.25 diopters, for example, 1 diopters. • An optical element having a distance vision portion with a power between 0.0 and 0.5 diopters, for example, 0.0 diopters, and an intermediate vision portion with a power between 1.25 and 1.5 diopters, for example, 1.5 diopters, and • An optical element having a distance vision portion with a diopter of 0.0 diopters and an intermediate vision portion with a diopter between 1.5 diopters and 2 diopters, such as 1.75 diopters.

[0080] The expected focal length map of the optical system 10 is the focal length for perspective vision TV at different parts of the optical system 10 (e.g., near vision part, intermediate vision part, and far vision part).

[0081] In this embodiment, the wearer's prescription is used to determine the expected power map. As previously explained, the prescription typically includes a power specific for distance vision and a down-concentration power specific for near vision. The power of the distance vision portion of an optical element conforming to the prescription (e.g., optical system 10) can be obtained directly from the distance vision portion of the prescription. The near vision power of the optical element conforming to the prescription can be obtained by adding the down-concentration power of the prescription to the power of the distance vision portion of the prescription.

[0082] In this embodiment, the desired focal length map is a monofocal focal length map. In this embodiment, the values ​​of the parameters of the front optics 13 and the rear optics 12 can be determined such that both provide monofocal power for a combination of perspective vision. In this embodiment, the front optics 13 may have 1 diopter of near-vision illumination. The values ​​of the parameters of the rear optics 12 are determined such that the combination of the front optics 13 and the rear optics 12 provides a focal length map for the wearer's prescription.

[0083] In these embodiments, the expected focal map is a progressive focal map. In these embodiments, the expected focal map may include a distance portion dedicated to distance vision and a near portion dedicated to near vision. The expected focal map may also include a central portion dedicated to intermediate vision. Figure 3 The method involves first selecting a front optics element 13. The front optics element 13 can be selected based on the wearer's prescription. For example, a front optics element 13 with a downlight (e.g., defined as the near focal power minus the distance focal power) higher than or equal to the prescribed downlight can be selected. Then, the values ​​of the parameters of the rear optics element 12 are determined by taking the wearer's prescription into account. In an embodiment, if the values ​​of the parameters of the rear optics element 12 are not feasible or do not meet predefined criteria, another front optics element 13 is selected, and other values ​​of the parameters of the rear optics element 12 are determined.

[0084] Therefore, using Figure 3 The method allows for the determination of the parameters of the optical system 10 through progressive correction and the simultaneous use of a finite set of front optical elements 13. This will allow for the manufacture of these front optical elements 13 using mass production techniques (injection or casting), thus reducing production costs.

[0085] In an embodiment, step 301, which selects the front optical element 13 from a group of up to six pre-defined front optical elements, and step 302, which determines the values ​​of the parameters of the rear optical element 12 based on the expected focal length map of the optical system 10 and the selected front optical element, can be implemented in the following manner: • Obtain the wearer's prescription and the wearer's physiological parameters, such as half pupillary distance and fitting height. • Determine the location of the portion of the optical system 10 covered by the waveguide 2. This location can be defined by the polar angles (α and β) of the gaze axis of the wearer's eye when the wearer is gazing at the supplementary image provided by the waveguide 2. • Determine the wearer's residual accommodation. Residual accommodation refers to the maximum focal power that the eye (more precisely, the lens of the eye) can provide to see as close as possible. The wearer's age can be used to determine residual accommodation. Prescription-added light can also be used, which is typically based on 2 / 3 of the residual accommodation. • Define the expected focal length map of the optical system 10 based on the wearer's prescription. • A pre-defined front optical element is selected from a pre-established group of front optical elements based on the position of the portion of the optical system 10 on which the waveguide 2 displays the image. In an embodiment, each pre-defined front optical element is associated with a range of the pre-defined front optical element. In an embodiment, when the portion of the optical system 10 on which the waveguide 2 displays the image includes the distance portion, the intermediate portion, and the near portion of the optical system 10, then a pre-defined front optical element whose front optical element has a front optical element with a front optical element whose front optical element has a front optical element close to but higher than the pre-defined front optical element with a front optical element. The front optical element's front optical element can be calculated by subtracting the focal power of the distance portion of the optical element from the focal power of the near portion. In an embodiment, when the portion of the optical system 10 on which the waveguide 2 displays the image includes only the intermediate and near portions of the optical system 10, then a pre-defined front optical element whose front optical element has a front optical element whose front optical element has a front optical element close to but higher than half of the pre-defined front optical element with a front optical element. • The value of the focal diagram of the rear optical element 12 is determined by subtracting the focal diagram of the selected front optical element from the expected focal diagram of the optical system 10. The value of the focal diagram of the rear optical element 12 can also be determined by optimizing the focal diagram of the rear optical element 12 based on the expected focal diagram of the optical system 10 and the focal diagram of the selected front optical element. To achieve this optimization, one can rely on the article “Application of optimization in computer-aided ophthalmic lens design” by Pascal Allione, Francoise Ahsbahs, and Gilles Le Saux, Proc. SPIE 3737, Design and Engineering of Optical Systems II, (August 27, 1999); https: / / doi.org / 10.1117 / 12.360002.

[0086] In an embodiment, Figure 3 The method may also include the step of determining the focal length of the corresponding portion of the rear optical element 12 by subtracting the focal length of the corresponding portion of the front optical element 13 from the focal length of the corresponding portion of the expected focal length map.

[0087] Figure 5 This represents another embodiment of a method for determining the values ​​of parameters of optical system 10.

[0088] exist Figure 5 In some embodiments, the method includes: • Step 501: Determining the values ​​of the parameters of the first portion of the front optical element 13 corresponding to the near-vision portion of the optical system 10 and the values ​​of the parameters of the second portion of the front optical element 13 corresponding to the far-vision portion of the optical system 10 based on the expected focal length map of the optical system. • Step 502: Determine the values ​​of the parameters of the first part of the rear optical element 12 corresponding to the near view portion of the optical system 10 and the values ​​of the parameters of the second part of the rear optical element 12 corresponding to the far view portion of the optical system 10 based on the expected focal length map of the optical system, and make the rear optical element 12 a step-back type. The near-view portion of the front optical element 13 can correspond to the near-view portion of the optical system 10. In this case, the first portion of the front optical element 13 is the near-view portion of the front optical element 13. The far-view portion of the front optical element 13 can correspond to the far-view portion of the optical system 10. In this case, the second portion of the front optical element 13 is the far-view portion of the front optical element 13. The near-view portion of the rear optical element 13 can correspond to the near-view portion of the optical system 10. In this case, the first portion of the rear optical element 12 is the near-view portion of the rear optical element 12. The far-view portion of the rear optical element 12 can correspond to the far-view portion of the optical system 10. In this case, the second portion of the rear optical element 12 is the far-view portion of the rear optical element 12.

[0089] In other words, Figure 5 The basic principle of the method is to use a specific combination of optical elements: • A rear optics element 12, the spherical power provided by which the wearer's gaze is shifted downwards, with greater accommodation required when viewing in the near portion (the bottom of the rear optics element) compared to the distance vision of the rear optics element when viewing supplementary images. The rear optics element 12 is also dependent on the wearer's prescription, particularly the prescription-added light. • A front optic element 13 that provides variable spherical power (typically a progressive lens, but may be a multifocal lens or other design) to compensate for the variable power of the rear optic element, and is designed such that the combination of the front and rear optic element lenses provides the wearer with prescriptions for both distance and near vision. • A waveguide 2 that provides a supplementary image at infinity.

[0090] The rear optical element 12 is a stepped-back type, which means that the focal power of the distance viewing part of the rear optical element 12 is higher than that of the near viewing part.

[0091] The receding rear optics element 12 allows for natural accommodation behavior when viewing the supplementary image from above. Wearers are accustomed to enhancing their accommodation when viewing from above in real-life scenarios. In fact, the power of the rear optics element 12 decreases as the gaze moves downward, so the wearer must enhance their accommodation when looking downward, which is a natural accommodation behavior.

[0092] In this embodiment, the front optics 13 and the rear optics 12 are designed such that the combination of the front optics 13 and the rear optics 12 provides a variable (PAL / anti-fatigue) or constant (SV) focal power adapted to see-through vision (TV). This focal power should satisfy the prescribed focal power for both distance and near vision. The total focal power depends on the eye's vertical gaze direction (α) and the associated world side distance Dist (α). Therefore, a real object at the corresponding world side distance in the line of sight will be virtually located at the new distance Dseethrough (α). This total focal power is defined according to the wearer's prescription and typically provides distance correction for the direct gaze direction and near correction for the downward gaze direction, as well as an intermediate value between the two. This total focal power can be a prescription for presbyopia, non-presbyopia (with a small amount of downlight for anti-fatigue), or even emmetropia.

[0093] Advantageously, the rear optics 12 can be designed to provide focal length for the supplementary image during supplementary vision SV, such that the new distance (the distance modified by the rear optics 12) makes Dvirtual(α) equal to or less than Dseethrough(α).

[0094] The near distance (the reciprocal of the distance, expressed in degrees) is less than the wearer's maximum accommodative ability. Conversely, the near distance must be greater than the wearer's far distance.

[0095] Dvirtual(α) can be configured to decrease as α decreases, allowing the wearer to gradually adjust as they view the supplementary image from top to bottom.

[0096] Here, in the following examples, it is assumed that the wearer is emmetropic but requires correction for near vision (presbyopic wearer, or a solution for visual fatigue with a small amount of downlighting). In the case of a wearer with refractive errors, distance refractive power needs to be added to the posterior optics 12.

[0097] Additionally, the following examples and methods present different designs for the rear and front optics, starting with the rear optics 12 and then determining the front optics 13. Other alternatives are also possible; for example, instead of using a completely custom-designed front optics 13, a pre-established group of front optics with different near and far powers can be used, and a front optics element can be selected from this group. Near and far powers can also be expressed as a couple power of the far power and the down-addition beam. The down-addition beam needs to be added to the far power to obtain the near power. For example, a pre-established front optics element whose characteristics (e.g., down-addition beam) are closest to those of the front optics 13 calculated according to the methods described below can be selected.

[0098] This method is based on design conditions, which can be analyzed and expressed using the following variables: Sfront(FV) = Spherical power of front optical element 13 when viewing distance. Sback(FV) = Spherical power of rear optical element 12 at a distance. Sfront (NV) = Spherical power of front optical element 13 at near vision Sback(NV) = Spherical power of rear optical element 12 at near vision Rx = Prescription Distance Focus Add = Prescription with added light Prox(NV) = Nearness of an object at close range P(FV) = Perspective vision (TV focal length) under distance viewing conditions P(NV) = Perspective TV focal length under near vision Acc = The lens will adjust to the maximum (and correspondingly comfortable) amount of the wearer's required adjustment.

[0099] The maximum adjustment can be approximated as follows (for the downlight value of the Gundam Prox (NV)): •Acc = 3 / 2(Prox(NV) - Add) [Formula 1] In the above formula, it is assumed that the lens under-illumination is prescribed such that the wearer uses 2 / 3 of its maximum accommodation when viewing near objects.

[0100] To adapt the combination of the front optics 13 and the rear optics 12, which provide either total variable (PAL / fatigue resistance) or constant (SV) focal power, to a perspective-vision TV, the total focal power can be considered in the first approximation as the sum of the front and rear focal powers: •Rx = Sfront(FV) + Sback(FV) [Formula 2] •Rx + Add = Sfront(NV) + Sback(NV) [Formula 3]

[0101] Considering that the focal length provided by the rear optical element 12 makes the virtual image appear closer than the perspective image, the following can be considered when viewing at a distance: Dvirtual(FV) <= Dseethrough(FV) Sback(FV) <= Sfront(FV) + Sba(FV) 0 <= Sfront(FV). The last formula allows the front optics to have positive or zero focal length, otherwise the wearer would need to make a relaxation adjustment.

[0102] When viewing near objects, consider: •Dvirtual(NV) <= Dseethrough(NV) •Sback(NV) <= Sfront(NV) + Sback(NV) – Prox(NV) •Prox(NV) <= Sfront(NV) [Formula 5]

[0103] To ensure that the apparent distance Dvirtual(α) of the supplementary image is less than the wearer's maximum accommodative ability, the following can be considered when viewing at a distance: •Rx – Sback(FV) <= Acc •Sback(FV) >= Rx – Acc [Formula 6] •Sfront <= Acc [Formula 7]

[0104] When viewing near objects, consider: •Rx – Sback(NV) <= Acc •Sback(NV) >= Rx – Acc [Formula 8] •Sfront(NV) – Add <= Acc •Sfront(NV) <= Acc + Add [Formula 9]

[0105] To make Dvirtual(α) decrease with angle α (a receding rear optical element), one could consider: •Sback(NV) <= Sback(FV) [Formula 10],

[0106] By combining the requirements associated with the post-optical components: [Formula 2] + [Formula 4] • 0 <= Rx – Sback(FV) •Sback(FV) <= Rx [Formula 11] [Formula 3] + [Formula 5] •Prox(NV) <= Rx + Add – Sback(NV) •Sback(NV) <= Rx + Add – Prox(NV) [Formula 12]

[0107] By combining [Formula 6], [Formula 8], [Formula 10], [Formula 11], and [Formula 12], the following conditions related to the focal length of the rear optical element are obtained: •Rx – Acc <= Sback(FV) <= Rx •Rx – Acc <= Sback(NV) <= Rx + Add – Prox(NV) •Sback(NV) <= Sback(FV)

[0108] In other words, when it is assumed that the wearer is emmetropic (otherwise, a distance vision is added to the rear optical element 12), Figure 5 The methods include: • Retrieve the wearer's prescription, which may include spherical power, cylindrical power, axis, and possibly subsurface illumination values. For the rear optical element 12, the distance of the supplementary image at the viewing distance is defined. Typically, this distance is set between 0.8m and 1.5m / 2m. Since waveguide 2 provides a supplementary image at infinity, the focal length of the rear optical element is defined as the reciprocal of the defined distance of the supplementary image. Sback(αFV) = -1 / Dvirtual(αFV) • Define the distance of the supplementary image at near vision. This distance is closer than the distance at far vision, making the accommodation requirement higher at near vision than at far vision, in accordance with perspective-based TV. The near viewing distance is determined based on the wearer's adjustment range. In fact, it is necessary to avoid making the supplementary image closer than the adjustment amplitude, otherwise the wearer will not be able to see the supplementary image clearly. One possible assumption is that the supplementary image is positioned at the same or slightly closer distance than the perspective distance: Dist(α) is defined according to the classical Aegmar function: it is infinity at far distance (α > 0), 33 cm at near distance (α = 30°), and the distance between the two is the midpoint. Dseethrough(α) = DistanceErgorama(α) Dvirtual (α) = k.DistanceErgorama(α), where k <= 1. Sback(α) = -1 / Dvirtual(α) • The focal power variation between near and far vision of the adjusted optical element 12 is designed to have negative under-illumination (gradually receding surface). The amount of negative under-illumination can be defined, or a focal power gradient can be defined, depending on the application of the supplementary image. For example, if it is necessary to have a continuous distance variation between near and far views and a large field of view (> 20°) in the supplementary image, it is preferable to have finite downlight (abs (downlight) < 1D, where "abs" means absolute value). Under the same circumstances, when it is desired to limit the display of the supplementary image to a small portion of the field of view (e.g., a small notification message in the far or near portion of the field of view), a larger under-illumination can be accepted because the distortion will be less visible in the case of a small supplementary image. Under the same conditions, when a large field of view is required in both the distance and near parts of the supplementary image, a large downlight can be used. However, a stable focal length region is used for both distance and near vision, resulting in a large focal length gradient and distortion outside the area where the supplementary image is displayed. • Define the values ​​of the parameters of the front optics 13. The front optics 13 is determined such that the combined power of the front optics 13 and the rear optics 12 (and possibly the waveguide 2, which may provide limited influence) provides the wearer with good correction corresponding to the wearer's prescription. This can be achieved, for example, by ray tracing: defining a focal length distribution target for the combination (which could be a progressive design or a single vision target), and modifying / optimizing the front surface of the front optics 13 to obtain a solution that is as close to the target as possible. Advantageously, to reduce manufacturing complexity, the front optical element 13 can be selected from a pre-defined group of front optical elements. In this case, only the rear optical element 12 can be optimized to attempt to achieve the desired focal length distribution of the combination of the front optical element 13 and the rear optical element 12.

[0109] In an embodiment, the determination of the values ​​of the parameters of the first portion of the front optical element 13 and the parameters of the second portion of the front optical element 13 is performed by selecting the front optical element 13 from a group of up to six pre-defined front optical elements introduced in a first embodiment of the method for determining the values ​​of the parameters of the optical system 10. Manufacturing of optical systems

[0110] In implementation Figure 3 Method or Figure 5 After the method is followed, the optical system 10 can be manufactured using the determined values ​​of the parameters of the optical system 10.

[0111] The rear optical element 12 can be manufactured by selecting a semi-finished lens with an adapted front surface and by applying digital surface treatment to the rear surface of the semi-finished lens according to the values ​​of the parameters of the rear optical element 12.

[0112] The front optic element 13 can also be manufactured in the same manner, or can be selected from a pre-defined set of front optic elements. Alternatively, a set of mass-produced lenses can be used, with a power step of 0.25D, and the lenses can be edged to the final frame shape to obtain the front optic element 13. Examples of parameter values ​​for an optical system

[0113] In the first example, we consider an emmetropic wearer with moderate downlighting (+1.5D).

[0114] Regarding the rear optical element 12, one can consider an optical element whose surface facing waveguide 2 is flat, while another surface is shaped to provide power. For distance viewing, the rear optical element 12 can provide zero power or a small amount of negative power (> -1.2D): •Sback(α FV) = -1.2D to 0D, where α > 0°

[0115] If, for distance vision, the rear optics 12 provides zero focal length, the supplementary image will be seen by the wearer at infinity: •Dvirtual(α FV) = -1 / Sback(α FV) = infinity

[0116] If the rear optics 12 provides a small negative focal length (e.g., -0.8D), the supplementary image will be seen closer than the surrounding elements, here: •Dvirtual(α > 0°) = -1 / Sback(α) = 1.25 m. Advantageously, a black optical element 12 that provides a small negative focal length can be used because it allows the front optical element to have a non-zero front curvature, which is more aesthetically pleasing.

[0117] The power of the near-vision portion of the rear optical element 12 can be selected based on the wearer's prescription. If the wearer's prescription includes +1.5D of additional light and the near-vision angle α is approximately 30°, then it has: •Dist(αNV) = 0.40m (proximity = -2.5D) •Dseethrough(αNV) = 1 / (2.5 - 1.5D) = 1m If you want the supplementary image and the perspective image to have the same distance, then you must make: •Sback(αNV) = -1 / Dvirtual(αNV) = -1 / Dseethrough(αNV) = -1D Therefore, the rear optical element 12 can have a focal length (gradient) varying from -0.8D to -1D, and can provide a gradient of -0.2D.

[0118] This is consistent with the derivation conditions on the back surface (assuming Prox(NV) = 2.5D): • -1.5 ≤ Sback(FV) ≤ 0 • -1.5 ≤ Sback(NV) ≤ -1 •Sback(NV) ≤ Sback(FV)

[0119] Regarding the values ​​of the parameters of the front optical element 13, it is advantageous to consider that the front surface is flat and the rear surface is curved.

[0120] For distance viewing, the focal length provided by the front optics 13 needs to be selected such that the combined focal length of the front optics 12 and the rear optics 13 provides zero focal length: •Stotal(αFV) = 0 •Stotal(αFV) = Sfront(αFV) + Sback(αFV) = 0D •Sfront(αFV) = +0.8D

[0121] For the near-vision portion of the front optics 13, a +1.5D downlight is required, therefore: •Stotal(αNV) = Sfront(αNV) + Sback(αNV) = 1.5D •Sfront(αNV) = 1.5D-(-1) = 2.5D

[0122] Using these parameters, a front optical element 13 with a front surface power varying from +0.8D to 2.5D was obtained.

[0123] In the second example, consider an emmetropic wearer with a high-low addendum (+2.5D). In this second example, the wearer has almost no accommodative amplitude.

[0124] If we assume Prox(NV) = 3D, then we obtain the following constraints: • 0 ≤ Sback(FV) ≤ 0 • 0 ≤ Sback(NV) ≤ 0 •Sback(NV) ≤ Sback(FV)

[0125] Regarding the viewing distance parameter of the rear optics 12, if the focal power is a small negative focal power (e.g., -0.8D), the supplementary image will be seen closer than the surrounding portion. In this case: •Dvirtual(αFV) = -1 / Sback(αFV) = 1.25m

[0126] Here, we assume the wearer has almost no accommodative amplitude, so he / she will use the remaining accommodation or depth of focus to see a clear image, potentially sacrificing some visual acuity. If the supplemental image resolution is lower than the eye's visual acuity, it may not actually reduce image quality.

[0127] Regarding the near-vision parameters of the rear optical element: •Dist(αNV) = 0.40m •Dseethrough(αNV) = 1 / (1 / 0.40 - 2.5) = infinity.

[0128] Here, we hope that Dvirtual(αNV) is closer than infinity, at least at the same distance as the line of sight, or closer (e.g., 1m).

[0129] Using Dvirtual(αNV) = 1m, this means Sback(αNV) = -1 / 1m = -1D.

[0130] Here, compared to distance vision, the wearer will again perceive the supplementary image at a closer distance and can use the remaining accommodation or depth of focus in an extended manner.

[0131] In this case, the rear optical element 12 is still receding, where the downlight = -0.2D.

[0132] This configuration is interesting because it provides low-light addition on the rear optics (thus the supplementary image distortion is low and the field of view is large), while making the supplementary image appear closer when viewing near than when viewing far.

[0133] A gradual, progressive design will be possible because negative under-illumination is low, and aberrations will be low. This is beneficial for supplementary images with a large field of view (20° to 50°).

[0134] Regarding the parameters of the front optical element 13, for distance viewing, it has: • Sfront(αFV) = +0.8D to make Stotal(αFV) = 0D. And for near vision, it has: •Sfront(αNV) = 2.5D-(-1D) = 3.5D

[0135] Therefore, for the front surface of the front optical element 13, a progressive surface with an under-illumination of +2.7D is used.

[0136] Figure 6 The second example represents a focal length diagram of the rear optical element 12, the front optical element 13, and the combination of the rear optical element 12 and the front optical element 13.

[0137] In the third example, we consider an emmetropic wearer with a lower add power (+0.75D). In this third example, the purpose of the lower add power is to have an anti-fatigue effect.

[0138] If we assume Prox(NV) = 3.0D, then we obtain the following constraints: • -3.375 ≤ Sback(FV) ≤ 0 •-3.375 ≤ Sback(NV) ≤ -2.25 •Sback(NV) ≤ Sback(FV)

[0139] For distance viewing, the rear optics 12 can provide a small negative focal length (e.g., Sback(αFV) = -0.8D), and the supplementary image will be seen closer than the surrounding area, here: •Dvirtual(αFV) = -1 / Sback(αFV)

[0140] For near vision, the following formula can be used for the rear optical element 12: •Dist(αNV) = 0.33m •Dseethrough(αNV) = 1 / (1 / 0.33 - 0.75D) = 0.444m.

[0141] Here, we want Dvirtual(αNV) to be the same as Dvirtual(αNV) = 0.444m, which means we can choose Sback(αNV) = -2.25D. In this case, the back optics are faded, where the downlight = -1.45D.

[0142] Regarding the values ​​of the parameters for the front optical element 13: • For the distance portion: Sfront(αFV) = +0.8D to make Stotal(αFV) = 0D. • For the near vision portion: Sfront(αNV) = 0.75D - (-2.25D) = 3D

[0143] Therefore, for the front surface of the front optical element 13, a progressive surface with a high under-illumination of +2.2D is used, even though the wearer's prescription has a low under-illumination.

[0144] Figure 7 The third example represents a focal length diagram of the rear optical element 12, the front optical element 13, and the combination of the rear optical element 12 and the front optical element 13.

[0145] In the fourth example, the situation is similar to that in the third example, but with the following differences: • For near vision, the wearer does not need additional light and uses a single vision lens. • Both the front optics 13 and the rear optics 12 use a sharp transition between the near and far vision portions. This type of front optics 13 and rear optics 12 is also referred to as a “wireless bifocal lens,” that is, a lens with a substantially constant power in its upper portion and a constant (different) power in its lower portion, and the transition between the two is continuous but as short as possible.

[0146] Figure 8 The fourth example represents a focal length diagram of the rear optical element 12, the front optical element 13, and the combination of the rear optical element 12 and the front optical element 13.

[0147] In the fifth example, consider a wearer with emmetropia who does not have sub-addition. In this fifth example, for distance vision, the optical system focuses the supplementary image closer to the surroundings, and for near vision, focuses the supplementary image very close. This fifth example results in high progressive sub-addition on the rear optics 12 and high progressive sub-addition on the front optics 13. Here, the aim is not to correct presbyopia, but simply to provide a more natural way to view the supplementary image. This natural way is achieved by having variable near power that increases as the wearer lowers their gaze direction.

[0148] If we assume Prox(NV) = 3.0D, then we obtain the following constraints: • -4.5 ≤ Sback(FV) ≤ 0 • -4.5 ≤ Sback(NV) ≤ -3 •Sback(NV) ≤ Sback(FV)

[0149] The telephoto portion of the rear optics 12 provides a small negative focal length (e.g., Sback(αFV) = -0.8D). The supplementary image will be seen closer than the surrounding area, here: •Dvirtual(αFV) = -1 / Sback(αFV) = 1.25m

[0150] For the near-vision portion of the rear optical element 12, the following formula is used: •Dist(αNV) = 0.33m •Dseethrough(αNV) = 0.33m, because there is no downlight. Here, we want Dvirtual(αNV) to be the same: •Dvirtual(αNV) = 0.33m, which means Sback(αNV) = -3D. In this case, the rear optical element 12 is stepped back, where the downlight is -2.2D.

[0151] For the viewing portion of the front optical element 13, the following is obtained: • Sfront(αFV) = +0.8D to make Stotal(αFV) = 0D. For the viewing portion of the front optical element 13, the following is obtained: • Sfront(αNV) = 3D, to compensate for the NV focal length of the rear optical element 12.

[0152] In this fifth example, a progressive front optics element 13 with a high under-illumination of +2.2D is used. Similarly, the rear optics element 12 has an under-illumination of 2.2D. This solution may be more relevant for supplementary images viewed with a narrow field of view, as a large under-illumination would provide a large level of aberration (unwanted astigmatism).

[0153] In the sixth example, consider a wearer with emmetropia who does not have sub-illuminate. In this sixth example, for distance vision, the optical system can make the focal point of the supplementary image closer than the surroundings, and for near vision, it can make the focal point of the supplementary image slightly closer than for distance vision. The fifth example results in a low-gradient sub-illuminate surface on the rear optics 12 and a low-gradient sub-illuminate surface on the front optics 13. Here, the aim is not to correct presbyopia, but simply to provide a more natural image with increased variable near as the wearer lowers his / her gaze direction. This would be advantageous for the supplementary image seen in a large field of view.

[0154] In this sixth example, the condition that the supplementary image under near vision is closer than the surrounding image under near vision is relaxed.

[0155] The telephoto portion of the rear optics 12 can provide a small negative focal length (e.g., Sback(αFV) = -0.8D). The supplementary image will be seen closer than the surrounding elements: Dvirtual(αFV) = -1 / Sback(αFV) = 1.25m

[0156] For the near-vision portion of the rear optical element 12, the following formula is used: •Dist(αNV) = 0.33m •Dseethrough(αNV) = 0.33m, because there is no downlight. Here, it is desirable to make Dvirtual(αNV) closer than 1.25m but not too high, in order to avoid large faded under-illumination on the rear optical element 12 and thus limit aberrations that would cause distortion of the supplementary image. •Dvirtual(αNV) = 0.77m, which means Sback(αNV) = -1.3D. In this case, the rear optical element 12 is stepped back, where the downlight is -0.5D.

[0157] For the distance-viewing portion of the front optical element 13, use: • Sfront(αFV) = +0.8D to make Stotal(αFV) = 0D. For the near-vision portion of the front optical element 13, use: •Sfront(αNV) = +1.3 D to compensate for the near focal length of the rear optical element 12.

[0158] Therefore, for the front optics 13, a progressive focal length is used, where the downlight is +0.5D. This solution uses a limited, progressively decreasing downlight, thus limiting unwanted astigmatism and optical distortion in the supplementary image.

[0159] Figure 9 The sixth example shows a focal length diagram of the rear optical element 12, the front optical element 13, and the combination of the rear optical element 12 and the front optical element 13.

Claims

1. A method for determining the values ​​of parameters of an optical system (10), The optical system (10) includes a front optical element (13), a rear optical element (12), and a waveguide (2). The rear optical element (12) is designed to be positioned closer to the wearer's eye than the front optical element of the optical system (10). The waveguide (2) is located between the front optical element (13) and the rear optical element (12). The waveguide (2) has an exit surface arranged to output an image to the wearer. The method includes: -Based on the expected focal length map of the optical system (10), determine (501) the values ​​of the parameters of the first portion of the front optical element (13) corresponding to the near vision portion of the optical system (10) and the values ​​of the parameters of the second portion of the front optical element (13) corresponding to the far vision portion of the optical system (10). -Based on the expected focal length map of the optical system (10), determine (502) the value of the parameter of the first part of the rear optical element (12) corresponding to the near vision portion of the optical system (10) and the value of the parameter of the second part of the rear optical element (12) corresponding to the far vision portion of the optical system (10), and make the rear optical element (12) a fade-out type.

2. The method according to claim 1, The waveguide (2) is configured such that the image is partially displayed in the far-view portion of the optical system (10) and partially displayed in the near-view portion of the optical system (10). The focal length of the first part of the rear optical element (12) is different from the focal length of the second part of the rear optical element (12).

3. The method according to claim 1 or 2, The determination of the values ​​of the parameters of the first part of the front optical element (13) and the values ​​of the parameters of the second part of the front optical element (13) is performed by selecting the front optical element from a group comprising up to 6 pre-defined front optical elements.

4. The method according to claim 3, The pre-defined front optical element has a distance vision portion with a focal power of less than 1.5 diopters.

5. The method according to claim 3 or 4, When the focal power of the distance-viewing portion of the first predetermined front optical element from the group of predetermined front optical elements is higher than the focal power of the distance-viewing portion of the second predetermined front optical element from the group of predetermined front optical elements, then the focal power of the near-viewing portion of the first predetermined front optical element is lower than the focal power of the near-viewing portion of the second predetermined front optical element.

6. The method according to any one of claims 1 to 5, The group comprises up to three pre-defined front optical elements.

7. The method according to claim 6, The pre-defined front optical element is selected from the following: • An optical element having a distance vision portion with a power between 0.25 and 0.75 diopters, for example, 0.5 diopters, and a near vision portion with a power between 1.5 and 2 diopters, for example, 1.75 diopters. • An optical element having a distance vision portion with a power between 0.0 and 0.5 diopters, for example, 0.0 diopters, and a near vision portion with a power between 2.5 and 3 diopters, for example, 2.75 diopters. • An optical element having a distance vision portion with a power between 0.0 and 0.5 diopters, for example, 0.0 diopters, and a near vision portion with a power between 3.25 and 3.75 diopters, for example, 3.5 diopters.

8. The method according to claim 6, The pre-defined front optical element is selected from the following: • An optical element having a distance vision portion with a power between 0.25 and 0.75 diopters, for example, 0.5 diopters, and an intermediate vision portion with a power between 0.75 and 1.25 diopters, for example, 1 diopters. • An optical element having a distance vision portion with a power between 0.0 and 0.5 diopters, for example, 0.0 diopters, and an intermediate vision portion with a power between 1.25 and 1.5 diopters, for example, 1.5 diopters, and • An optical element having a distance vision portion with a diopter of 0.0 diopters and an intermediate vision portion with a diopter between 1.5 diopters and 2 diopters, such as 1.75 diopters.

9. The method according to any one of claims 1 to 8, The expected focal length map is determined using the wearer's prescription.

10. The method according to claim 9, The front optical element (13) is selected based on the prescription under-illumination and possibly the position of the portion of the optical system (10) on which the waveguide (2) displays the image.

11. The method according to any one of claims 1 to 8, The expected focal length map is a single focal length map.

12. The method according to any one of claims 1 to 8, The expected focal length map is a progressive focal length map.

13. A method for manufacturing an optical system (10), The optical system (10) includes a front optical element (13), a rear optical element (12), and a waveguide (2). The rear optical element (12) is designed to be positioned closer to the wearer's eye of the optical system (10) than the front optical element (13). The waveguide (2) is located between the front optical element (13) and the rear optical element (12). The waveguide (2) has an exit surface arranged to output an image to the wearer. The method includes: -Based on the expected focal length map of the optical system (10), determine (501) the values ​​of the parameters of the first portion of the front optical element (13) corresponding to the near vision portion of the optical system (10) and the values ​​of the parameters of the second portion of the front optical element (13) corresponding to the far vision portion of the optical system (10). -Based on the expected focal length map of the optical system (10), determine (502) the values ​​of the parameters of the first portion of the rear optical element (12) corresponding to the near vision portion of the optical system (10) and the values ​​of the parameters of the second portion of the rear optical element (12) corresponding to the far vision portion of the optical system (10), and make the rear optical element (12) a fade-out type. - The optical system (10) is manufactured based on the determined values ​​of the parameters.

14. An optical system (10). The optical system (10) includes a front optical element (13), a rear optical element (12), and a waveguide (2). The rear optical element (12) is designed to be positioned closer to the wearer's eye of the optical system (10) than the front optical element (13). The waveguide (2) is located between the front optical element (13) and the rear optical element (12). The waveguide (2) has an exit surface arranged to output an image to the wearer. The values ​​of the parameters of the first portion of the front optical element (13) corresponding to the near vision portion of the optical system (10) and the values ​​of the parameters of the second portion of the front optical element (13) corresponding to the far vision portion of the optical system (10) are determined based on the expected focal length map of the optical system (10). The values ​​of the parameters of the first part of the rear optical element (12) corresponding to the near-view portion of the optical system (10) and the values ​​of the parameters of the second part of the rear optical element (12) corresponding to the far-view portion of the optical system (10) are determined based on the expected focal length map of the optical system (10), and the rear optical element (12) is a fade-out type.

15. An eye-worn device (EY), comprising: Optical system (10). The optical system (10) includes a front optical element (13), a rear optical element (12), and a waveguide (2). The rear optical element (12) is designed to be positioned closer to the wearer's eye of the optical system (10) than the front optical element (13). The waveguide (2) is located between the front optical element (13) and the rear optical element (12). The waveguide (2) has an exit surface arranged to output an image to the wearer. The values ​​of the parameters of the first portion of the front optical element (13) corresponding to the near vision portion of the optical system (10) and the values ​​of the parameters of the second portion of the front optical element (13) corresponding to the far vision portion of the optical system (10) are determined based on the expected focal length map of the optical system (10). The values ​​of the parameters of the first part of the rear optical element (12) corresponding to the near-view portion of the optical system (10) and the values ​​of the parameters of the second part of the rear optical element (12) corresponding to the far-view portion of the optical system (10) are determined based on the expected focal length map of the optical system (10), and the rear optical element (12) is a fade-out type.

Images