Augmented reality contact lenses and methods

Abstract

The augmented reality contact lens (100) comprises a transparent body (102) designed to be placed on an eye (104) and at least one augmented reality module. The augmented reality module comprises a light source (114) attached to the transparent body (102) and designed to emit light onto the transparent body, and an optical element (116) attached to the transparent body (102) and designed to receive light from the light source (114) and direct the light towards the eye (104). The optical element (116) is a hologram 116 designed to diffract the received light towards the eye 104 as a holographic image.

Description

[Technical Field]

[0001] The present invention relates to a contact lens for augmented reality and a method thereof. [Background technology]

[0002] Augmented reality is known as the superimposition of images, such as text, symbols, drawings, etc., onto the actual scene captured by the eye. Augmented reality is the basis of Extended Reality (XR) and Mixed / Merged Reality (MR).

[0003] The US patent published as Patent Document 1 describes an example of an augmented reality device: a transparent body designed to rest on the eye; a light source attached to the transparent body and designed to emit light into the transparent body; - an optical element attached to the transparent body and designed to receive light from a light source and direct this light towards the eye; The present invention describes an augmented reality contact lens comprising:

[0004] In this document, the light source is a pixel matrix. In one particular embodiment, the contact lens comprises a mirror for reflecting light towards an optical element that is a focusing lens, so that an image of the pixel matrix is focused on the retina of the eye.

[0005] This assembly has the disadvantage that it is relatively complex to implement, is bulky, and can present optical alignment problems that can obscure the user's view of the environment.

[0006] Patent application published as U.S. Patent No. 5,999,237 describes a contact lens in which a pixel matrix is generated by an optical waveguide comprising a plurality of light lines and a light source adapted to illuminate the light lines. Each pixel of the matrix is activated by locally applying an electric field via electrodes to locally change the refractive index of the light lines. The contact lens further includes a hologram configured to focus the light rays emitted from the pixel matrix onto the center of the eye's pupil to achieve Maxwellian vision.

[0007] Again, this assembly has the drawback of being relatively complex to implement: it is bulky and can present optical alignment problems that can obscure the user's view of the environment. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 8,786,675 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-311823 Summary of the Invention [Problem to be solved by the invention]

[0009] It would therefore be desirable to provide a contact lens for augmented reality that allows for obviating at least some of the problems and limitations mentioned above. [Means for solving the problem]

[0010] So, a transparent body designed to rest on the eye; a light source attached to the transparent body and designed to emit light into the transparent body; - an optical element attached to a transparent body and designed to receive light from a light source and direct the light toward the eye; A contact lens for augmented reality comprising: A contact lens for augmented reality is proposed, characterized in that the optical element is a hologram designed to diffract received light in the direction of the eye as a holographic image. Therefore, the light source can be extremely simple and small, since it only needs to emit light and not create an image as in a pixel matrix. In fact, according to the invention, the image is created by a hologram. In particular, such a light source can be much smaller than a pixel matrix.

[0011] Optionally, the augmented reality contact lenses according to the present invention may further include some or all of the following features, either alone or in combination: - the light source is monochromatic and / or point-like, the contact lens further comprises an optical waveguide designed to guide light from the light source to the hologram; the optical waveguide comprises a transparent substrate and a layer of reflective material covering an outer surface of the transparent substrate; at least one of the light source and the hologram is disposed within the transparent substrate such that it is partially or completely surrounded by the transparent substrate; the contact lens comprises a wireless receiver attached to the transparent body and designed to receive commands, and a module for selectively activating an augmented reality module according to the received commands; the selective activation module comprises a refractive index-altering device designed to alter the refractive index of the optical waveguide to alter illumination of the hologram such that the hologram ceases to provide a holographic image; The selective activation module is designed to deactivate the light source; The contact lens has a central area consisting of only transparent material.

[0012] Also, - placing the transparent body of the contact lens on the eye; - emitting light onto the transparent body from a light source attached to the transparent body; - receiving light by an optical element attached to the transparent body and directing the light towards the eye through the optical element; 1. An augmented reality method comprising: A method of augmented reality is also proposed, characterized in that the optical element is a hologram and that the light sent towards the eye is light in the form of a holographic image diffracted by the hologram.

[0013] The invention will be better understood from the following description, given by way of example only and made with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view of an augmented reality contact lens according to the present invention and an eye on which the augmented reality contact lens is placed. [Figure 2] FIG. 2 is a rear view of the augmented reality contact lens of FIG. 1, i.e., as the contact lens is viewed from the eye. [Figure 3] FIG. 2 is a view similar to FIG. 1 showing elements of a contact lens in more detail. [Figure 4] FIG. 2 is a functional diagram of an electronic module for controlling the light source of the contact lens of the previous figure. [Figure 5] 1 is a flowchart illustrating an augmented reality method according to an embodiment of the present invention. [Figure 6] FIG. 1 is a rear view of an augmented reality contact lens according to one embodiment of the present invention. [Figure 7] 7 is a cross-sectional view of the contact lens of FIGS. 1-3 or 6 when an augmented reality device is encapsulated in the transparent body of the contact lens. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] In the following, an augmented reality contact lens 100 according to the present invention will be described with reference to FIG.

[0016] The contact lens 100 is designed to be applied to the eye 104, where the optical axis AO and the visual axis AV intersect at point O. As is known per se, the eye 104 comprises a spherical cornea 106 at its interface with the surrounding air. The eye 104 also comprises an iris 122, which is pierced in its center by a circular opening called the pupil 123, through which light passes. The iris 122 dilates and constricts depending on the light intensity. The eye 104 also comprises a crystalline lens 118, formed of a transparent, flexible fibrous disk, to focus the incoming light received through the pupil 123. The intersection point O is usually located near the center of the crystalline lens 118. Behind the crystalline lens 118, opposite the eye cavity 109, the eye 104 also comprises a retina 110, formed of sensory cells including cones for day vision and rods for night vision. The retina 110 has a central region, called the fovea centralis 111, in the extension of the visual axis AV, where detailed vision is most precise. Thus, the fovea 111 is decentered by several degrees relative to the optical axis AO. The retina 110 also has an area around the fovea 111 called the parafoveal 112, which corresponds to peripheral vision. As shown in Figure 1, the cornea 106, the pupil of the iris 122, and the crystalline nucleus 118 are substantially centered on the optical axis AO.

[0017] First, contact lens 100 comprises a transparent body 102 designed to rest on eye 104 .

[0018] The transparent body 102 has a domed, disc-like shape centered on a central axis AC, with a concave posterior surface 1004 and a convex anterior surface 1003. The posterior surface 1004 has a shape complementary to the cornea 106 so that it presses against the cornea 106 in the preferred position of the contact lens 100 shown in Figure 1. In this preferred position, the contact lens 100 is centered on the optical axis AO such that the central axis AC of the transparent body 102 is substantially coincident with the optical axis AO.

[0019] Since the transparent body 102 is in contact with the cornea 106, it is made of a biocompatible material such as a silicone hydrogel or HEMA (hydroxyethyl methacrylate) based material, or any other suitable material as described by C. Stephen, A. Musgrave, and F. Fang in their article entitled "Contact Lens Materials: A Materials Science Perspective" published in the journal Materials, Volume 14, 261, January 2019.

[0020] The contact lens 100 further comprises an augmented reality device 107 encapsulated within the transparent body 102 of the contact lens 100 .

[0021] The augmented reality device 107 will now be described in more detail with reference to FIG. The augmented reality device 107 has, for example, a generally flattened coronal or generally flattened annular shape whose center is located on the central axis AC of the transparent body 102. The augmented reality device 107 includes a transparent substrate 105 intended to guide light as will be described later. The transparent substrate 105 includes, for example, liquid crystal.

[0022] The augmented reality device 107 further comprises at least one augmented reality module 108. In the example shown in Figure 2, there are eight augmented reality modules 108, distributed in a star shape such that each augmented reality module 108 is aligned along one branch of the star.

[0023] The augmented reality device 107 further comprises a control module 10 for the augmented reality module 108 attached to the transparent substrate 105. This control module 10 will be described in more detail below with reference to FIG.

[0024] Each augmented reality module 108 is designed to generate an image on the retina 110 that is superimposed on a real-world scene perceived by the eye 104 when the contact lens 100 is in its preferred position on the eye 104. In the described example, the image is a warning sign that is intended to appear in peripheral vision. Thus, in the described example, the image is preferably generated at the parafovea 112. Also, again in the described example, each augmented reality module 108 is designed to provide a different image on the retina 110. Thus, in this example, up to eight different images can be displayed at the parafovea 112.

[0025] The augmented reality modules 108 are similar to each other, so only one of them will be described in detail below.

[0026] First, the augmented reality module 108 comprises a light source 114 attached to the transparent substrate 105 and designed to emit light into the transparent substrate 105 .

[0027] Preferably, the light source 114 is punctiform, i.e., the light output is less than 100 μm, and monochromatic, i.e., the light emitted by the light source has a single-wavelength emission peak with a half-width of at most 100 nm. This peak is in the visible range of approximately 400-750 nm, preferably green or red: 500-670 nm. Alternatively, the peak is at the wavelength of sensitivity of the photoreceptors in the retina 110, more specifically the parafoveal 112 (e.g., 420 nm for rods and 534 nm for cones). Even more preferably, the light source 114 has a divergence angle of less than 40°.

[0028] For example, the light source 114 may comprise a laser, more particularly at least one vertical cavity surface emitting laser, known as a VCSEL. Indeed, the compactness of this type of light source advantageously allows the thickness of the contact lens 100 to be significantly reduced compared to the pixel matrices used in prior art contact lenses.

[0029] The augmented reality module 108 further comprises a hologram 116 attached to the transparent substrate 105 and designed to receive light from the light source 114 and direct this light towards the eye 104, more specifically through the pupil 123 towards the crystal 118. The hologram 116 is a diffractive optical element, commonly referred to by the acronym DOE (Diffractive Optical Element). The hologram 116 is therefore designed to diffract the received light towards the eye 104 as a holographic image. This transformation is based on the phenomenon of optical diffraction, so that the diffracted light (holographic image) corresponds, for example, to the Fresnel transform or the spatial Fourier transform of the final image focused on the retina 110. The design of the hologram preferably takes into account the tissues through which the light passes.

[0030] Thus, the hologram 116 is generally configured to create and project a desired final image onto the retina of the eye. Specifically, the structure of the hologram defines this image. As noted above, in some embodiments, the hologram may be configured to perform a spatial inverse Fourier transform of the final image projected onto the retina. In other embodiments, the hologram may be configured to perform additional optical functions, such as a Fresnel transform of the desired image.

[0031] In practice, hologram 116 comprises a piece of transparent substrate of a certain thickness, such as a glass plate, on or within which are formed micro- or nanostructures configured to diffract an incident wavefront to produce a holographic image. These micro- or nanostructures form a diffraction pattern. Alternatively, hologram 116 can be in the form of a reflective mirror that can operate in reflection instead of in transmission.

[0032] The hologram 116 is obtained, for example, by depositing a layer of photosensitive resin (e.g., S1813 type) about 1.2 μm thick on the surface of the transparent body 102 in an area facing one edge of the pupil 123 when the contact lens 100 is in a suitable position on the eye 104. The area surrounding the hologram 116 is then sufficiently exposed to light so that the phase profile of the multilayer phase is photoetched into the resin. In a development step, the resin around the hologram 116 is removed, imprinting the hologram 116 into the resin layer. The hologram 116 thus obtained has, for example, a resolution of about 750 nm with an indentation depth of about 1000 nm.

[0033] To avoid obstructing the central vision of the eye 104, the contact lens 100 preferably has a central region 120 formed solely of the transparent body 102. This central region 120 is located on the optical axis AO in front of the pupil 123 when the transparent body is in a suitable position on the eye 104. Thanks to this central region 120, the pupil 123 is, at least in part, free from elements that may impair vision.

[0034] In particular, in the described example, the holograms 116 of the various augmented reality modules 108 are arranged in a ring around a central region 120. The coronal holograms 116 have a maximum radius equal to the pupil dilation (maximum pupil opening, e.g., 8 mm) and a minimum radius (e.g., 2 mm) that leaves the central region of the pupil 123 clear, meaning that the pupil 123 can vary between these two values. Thus, in the described example, the radial dimension of each hologram 116 is a maximum of 6 mm. If the pupil 123 were equal to the minimum radius of the coronal hologram, it would not be possible to project it onto the retina 110. In all other cases, at least a partial holographic image of the pattern of the hologram 116 would still pass through the pupil 123, so that an image would always be formed on the retina, even if the hologram 116 was only partially transparent. This is sufficient to allow the final image to appear on the retina 110 in this hologram's design mode, but at the cost of a reduced illumination level at the retina 110. In fact, because hologram 116 contains a periodic pattern, even if part of hologram 116 is blocked by pupil 123, a holographic image can still be generated that is focused through crystal 118 onto retina 110, but at a lower intensity and possibly lower resolution than if hologram 116 were not partially blocked by pupil 123.

[0035] Referring to FIG. 3, central region 120 preferably has a diameter d of at least 3 mm about central axis AC to adequately clear pupil 123 .

[0036] To prevent some of the light emitted by the light source 114 from exiting the transparent substrate 105 before reaching the hologram 116, the contact lens 100 further includes a layer of reflective material 124 that at least partially covers the surface of the transparent substrate 102 except for the central region 120 so as not to obstruct the central vision of the eye 104. Thus, the transparent substrate 105 and the layer of reflective material 124 form an optical waveguide that directs light from the light source 114 to the associated hologram 116.

[0037] Outside the central region 120, the layer of reflective material 124 does not necessarily extend across the entire remaining surface of the transparent substrate 105. For example, the peripheral edge 1001 of the transparent substrate 105 may be free of the layer of reflective material 124.

[0038] For example, the layer of reflective material 124 comprises gold, in which case very thin reflective layers, on the order of a few nanometers, can be advantageously produced, for example by "lift-off" photolithography techniques. Alternatively, the reflective material layer 124 includes aluminum or silver to advantageously improve the strength and reflectivity of the reflective material layer 124 .

[0039] 3, light source 114 and hologram 116 are disposed within transparent substrate 105 such that they are partially surrounded by and flush with transparent substrate 105. Alternatively, one or both may be completely surrounded by transparent substrate 105.

[0040] Referring now to FIG. 4, an example embodiment of control module 10 will be described in more detail. Firstly, the control module 10 comprises a power supply 130, such as a battery 130. In particular, the power supply 130 is designed to power the light sources 114 of each augmented reality module 108.

[0041] The control module 10 further comprises means for charging the battery 132, for example inductively. The control module 10 further comprises a wireless receiver Rx, for example Wi-Fi, designed to receive the commands C.

[0042] The contact lens 100 further comprises a module 136 for selectively activating the augmented reality module 108 based on the received command C. For example, the selective activation module 136 comprises a switch 1361 connected between the battery 130 and the light source 114.

[0043] An example of an augmented reality method 500 will now be described with reference to FIG. Specifically, the method is described for use with one of the augmented reality modules 108, but the method may apply to each of the augmented reality modules 108. In step E1, the contact lens 100 is placed on the eye 104 so that the transparent body 102, or more precisely its posterior surface 1004, is positioned in the desired position on the cornea 106 as shown in FIGS. The augmented reality module 108 is not initially activated and therefore will not provide holographic images.

[0044] In step E2, the selective activation module 136 receives, via the receiver Rx, a command C instructing the activation of the augmented reality module 108.

[0045] In step E3, the selective activation module 136 responds to command C by activating the augmented reality module 108 indicated by command C to provide the holographic image. In the example shown, the switch 1361, which was initially in the open position, is closed so that the power supply 130 powers the light source 114.

[0046] In step E4, the now powered light source 114 emits light that is guided into the interior of the transparent body 102 by optical reflection between the layers 124 of reflective material.

[0047] In step E5, the hologram 116 associated with this light source 114 receives the guided light.

[0048] In step E7, the hologram 116 diffracts the received light to form a holographic image that is directed towards the eye 104, more precisely towards the pupil 123. 3, the light rays are represented as dotted lines to simplify visualization of the light paths. In reality, multiple light rays are emitted by the light source 114 to form the light beam.

[0049] In step E9, the crystal 118 receives the waves diffracted by the hologram and participates in the reconstruction of the final image on the retina 110 (corresponding to this holographic image).

[0050] In this way, the final image of the virtual object appears on the retina 110 and is superimposed on the real scene seen by the eye 104. In the described example, optical reconstruction is performed in the parafovea 112 so that the final image appears in the peripheral vision of the eye 104.

[0051] Specifically, the image of the virtual object is projected at a position approximately 10° from the fovea 111 (or equivalently from the optical axis AO) with respect to point O so as not to obstruct central vision, corresponding to 12°-15° from the optical axis AO with respect to point O. The final image preferably extends over a maximum of 2° (approximately 4 quadrants) of the visual field, corresponding to a length of approximately 1.15 mm on the retina 110. At such a distance from the fovea 111, neural resolution is significantly reduced compared to the fovea 111, so the smallest detail in the final image must be at least 48 micrometers to be perceived.

[0052] In step E10, the selective activation module 136 receives, via the receiver Rx, a command C instructing the augmented reality module 108 to deactivate.

[0053] In step E11, the selective activation module 136 responds to command C by stopping the augmented reality module 108 indicated by command C from providing any more holographic images. In the described example, switch 1361 is opened so that the power supply 130 no longer supplies power to the light source 114 and the light source stops emitting light.

[0054] Referring to FIG. 6, a contact lens 100' according to another embodiment of the present invention is illustrated. This embodiment variant differs from the previous embodiment described above essentially in the number of augmented reality modules (four instead of eight) and in the method of selectively activating and deactivating the holograms intended to be transmitted in the direction of the eye.

[0055] According to this embodiment, the light source 114 emits light continuously, and the selective activation module 136 comprises a refractive index-modifying device 140 for each hologram 116. This refractive index-modifying device 140 is designed to modify the refractive index of the transparent substrate 105, for example by means of the liquid crystals it contains. In fact, this liquid crystal is a birefringent electro-optical component, whose refractive index changes upon application of an electric field. When the refractive index changes, the light guiding conditions (e.g., deflection angle) change, so that the hologram 116 is no longer illuminated to provide a holographic image.

[0056] For example, the refractive index-altering device 140 comprises at least one pair of electrodes designed to generate an electric field that alters the refractive index in at least one direction. In the described example, these electrodes are made of a plate of reflective material 124. Specifically, the reflective material 124 comprises a large annular portion 124A on the front surface of the transparent substrate 105 and a small annular portion 124B on the rear surface of the transparent substrate 105. The small annular portion 124B is divided into four segments 142A, 142B, 144A, 144B that are electrically isolated from each other and connected to the control device 10'. Each pair of opposing segments forms a pair of electrodes.

[0057] Thus, upon receiving command C, the selective activation module 136 is designed to apply a voltage between the electrodes associated with the augmented reality module 108 associated with command C in order to change the refractive index of the transparent substrate 105 extending between the electrodes. Thus, the hologram 116 of the augmented reality module 108 is not properly illuminated to provide a holographic image.

[0058] Referring to Figure 7, the transparent body 102 comprises, for example, a base 102A having a housing 702 for receiving an augmented reality device 107 or 107', and a cover 102B designed to cover the base and the augmented reality device 107 or 107' received in the housing 702.

[0059] From the above description, it is well understood that it is a hologram that creates a holographic image when illuminated by a light source. In this case, the light source provides neutral light that does not contain any image or image information (e.g., a beam of light with uniform intensity). A hologram illuminated only by the light source can therefore create an image in the direction of the eye. In contrast to prior art approaches, no screen or pixel matrix is required. In particular, the light source can be as simple as a point light source that only illuminates the hologram.

[0060] It is clear that such augmented reality contact lenses make it possible to superimpose an image onto the retina of the eye over the real scene perceived by the eye in a compact and simple manner. It should also be noted that the present invention is not limited to the above-described embodiments, and various modifications to the above-described embodiments will be apparent to those skilled in the art in light of the teachings disclosed immediately above.

[0061] In particular, the nature and emission characteristics of the light source can be adapted depending on the intended application. Additionally, optical elements such as Fresnel lenses can be placed between the light source 114 and the hologram 116 to shape the beam for improved imaging conditions.

[0062] In the foregoing detailed description of the present invention, the language used should not be construed as limiting the invention to the embodiments disclosed herein, but should be construed as including equivalents that are within the scope of prediction of one skilled in the art by applying his or her general knowledge to carry out the disclosed teachings.

Claims

1. a transparent body (102) designed to rest on the eye (104); at least one augmented reality module (108); Equipped with The at least one augmented reality module (108) a light source (114) attached to said transparent body (102) and designed to emit light into said transparent body (102); an optical element (116) attached to the transparent body and designed to receive the light from the light source (114) and direct the light in the direction of the eye (104); Equipped with A contact lens (100; 100') for augmented reality, the light source (114) is adapted to emit image-free light that is received by the optical element (116), and the optical element (116) is a hologram designed to diffract the received light to generate a holographic image in the direction of the eye (104); Further, it has a central region (120) consisting of only the transparent body (102), a light guide (105, 124) designed to guide the light from the light source (114) to the hologram (116); A contact lens (100; 100') for augmented reality, characterized by:

2. The lens of claim 1 , comprising a plurality of augmented reality modules (108), each module (108) designed to provide a different final image on the retina (110) of the eye (104).

3. 3. A contact lens (100; 100') according to claim 1 or 2, wherein the light source (114) is monochromatic and / or point-like.

4. 2. The contact lens (100; 100') of claim 1, wherein the light guide comprises a transparent substrate (105) and a layer (124) of reflective material covering an outer surface of the transparent substrate (105).

5. 5. The contact lens (100; 100') of claim 4, wherein at least one of the light source (114) and the hologram (116) is disposed within the transparent substrate (105) so as to be partially or completely surrounded by the transparent substrate (105).

6. a radio receiver (Rx) attached to said transparency (102) and designed to receive commands (C); a module (136; 136') for selectively activating each augmented reality module (108) according to said received command (C); A contact lens (100; 100') according to any one of claims 1 to 5, comprising:

7. 7. The contact lens (100; 100') of claim 6, wherein the selective activation module (136') comprises a refractive index-changing device (140) designed to change the refractive index of the optical waveguide (105, 124) to change the illumination of the hologram (116) so that the hologram (116) ceases to provide the holographic image.

8. 8. The contact lens (100; 100') of claim 7, wherein the selective activation module (136) is designed to deactivate the light source (114).

9. - placing (E1) the transparent body (102) of the contact lens (100) on the eye (104); - a step (E4) of emitting light into said transparent body (102) from a light source (114) attached to said transparent body (102); receiving (E5) said light by an optical element (116) attached to said transparent body (102) and transmitting (E7) said light towards said eye (104) through said optical element (116); An augmented reality method (500) comprising: the light emitted by the light source (114) and received by the optical element (116) does not contain an image, and the optical element (116) is a hologram designed to diffract the received light to produce a holographic image in the direction of the eye (104); Furthermore, the contact lens (100) has a central region (120) consisting solely of the transparent body (102), the contact lens (100) comprises an optical waveguide (105, 124) designed to guide the light from the light source (114) to the hologram (116); An augmented reality method, comprising:

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