Augmented reality contact lenses and corresponding methods

Abstract

An augmented reality contact lens (100) includes: a transparent body (102) designed to be placed on an eye (104); and at least one augmented reality module, the at least one augmented reality module including a light source (114) attached to the transparent body (102) and designed to emit light into 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 toward the eye (104). The optical element (116) is a hologram designed to diffract the received light in the form of a holographic image toward the eye (104).

Description

Technical Field

[0001] The present invention relates to contact lenses for augmented reality and methods thereof. Background Art

[0002] By augmented reality, we understand the fact of superimposing images representing text, symbols, or drawings, etc. onto the real scene captured by the eyes. Augmented reality is the basic principle of extended reality (XR) and mixed / merged reality (MR).

[0003] As an example of an augmented reality device, U.S. Patent No. 8,786,675 B2 describes an augmented reality contact lens comprising:

[0004] a transparent body designed to be placed on the eye;

[0005] - an optical light source attached to the transparent body and designed to emit light into the transparent body; and

[0006] An optical element attached to the transparent body and designed to receive light from a light source and to transmit the light in the direction of the eye. In this document, the optical light source comprises a pixel matrix. In a specific embodiment, the contact lens comprises a reflector for reflecting light back to the optical element, which acts as a converging lens, so that an image of the pixel matrix is ​​focused on the retina of the eye.

[0007] The downside of this component is that it is relatively complex to implement, it is bulky, and it can present optical alignment issues, potentially obscuring the user's view of their surroundings.

[0008] Patent application published as JP2005311823 describes a contact lens in which a pixel matrix is ​​generated by a light guide comprising a plurality of optical lines and a light source adapted to illuminate these optical lines. An electric field is locally applied via electrodes to activate each pixel in the matrix, thereby locally changing the refractive index of the optical lines. The contact lens also includes a hologram configured to converge luminous radiation emitted from the pixel matrix at the center of the pupil of the eye, thereby achieving Maxwell illumination.

[0009] Again, the downside of this assembly is that it is relatively complex to implement, is bulky, and can present optical alignment issues, potentially obscuring the user's view of their surroundings.

[0010] Therefore, it may be desirable to provide contact lenses for augmented reality that enable at least some of the above-mentioned problems and limitations to be eliminated. Summary of the Invention

[0011] Therefore, a contact lens for augmented reality is proposed, comprising:

[0012] a transparent body designed to be placed on the eye;

[0013] - an optical light source attached to the transparent body and designed to emit light into the transparent body; and

[0014] an optical element attached to the transparent body and designed to receive light from the light source and to send it in the direction of the eye;

[0015] The invention is characterized in that the optical element is a hologram designed to diffract received light into a holographic image in the direction of the eye.

[0016] The light source can therefore be very simple and compact, since it does not need to generate an image like a pixel matrix, but simply emits light. In fact, according to the present invention, the image is generated by a hologram. In particular, such a light source can be more compact than a pixel matrix.

[0017] Optionally, the augmented reality contact lens according to the present invention may further include any one or all of the following features, alone or in combination:

[0018] - the light source is monochromatic and / or point-shaped;

[0019] - the contact lens further comprises a light guide designed to guide light from the light source to the hologram;

[0020] - the light guide comprises a transparent substrate and a layer of reflective material, the layer of reflective material covering an outer surface of the transparent substrate;

[0021] - at least one of the light source and the hologram is arranged within the transparent substrate so as to be partially or completely surrounded by the transparent substrate;

[0022] - the contact lens comprises: a radio receiver attached to the transparent body and designed to receive commands; and a module for selectively activating the augmented reality module according to the received commands;

[0023] - the selective activation module comprises refractive index changing means designed to change the refractive index of the light guide in order to change the illumination of the hologram so that the hologram ceases to provide a holographic image;

[0024] - the selective activation module is designed to deactivate the light source; and

[0025] - The contact lens has a central area consisting only of a transparent body.

[0026] An augmented reality method is also proposed, which includes:

[0027] - placing the transparent body of the contact lens on the eye;

[0028] - emitting light from a light source attached to the transparent body into the transparent body; and

[0029] - receiving light through an optical element attached to the transparent body and sending the light through the optical element in the direction of the eye;

[0030] It is characterized in that the optical element is a hologram, and the light sent in the direction of the eye is light diffracted by the hologram in the form of a holographic image. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The invention will be better understood with the aid of the following description, given by way of example only and with reference to the accompanying drawings, in which:

[0032] [ Figure 1 ] Figure 1 is an augmented reality contact lens according to the present invention and a cross-sectional view of the augmented reality contact lens arranged on an eye;

[0033] [ Figure 2 ] Figure 2 yes Figure 1 a rear view of the augmented reality contact lens of FIG. 1 , i.e., the augmented reality contact lens when the contact lens is viewed from the eye;

[0034] [ Figure 3 ] Figure 3 is with Figure 1 A similar view with the elements of the contact lens in greater detail;

[0035] [ Figure 4 ] Figure 4 is a functional view of an electronic module for controlling the light source of the contact lens of the aforementioned figures;

[0036] [ Figure 5 ] Figure 5 is a flowchart describing an augmented reality method according to an embodiment of the present invention;

[0037] [ Figure 6 ] Figure 6 is a rear view of an augmented reality contact lens according to an embodiment of the present invention; and

[0038] [ Figure 7 ] Figure 7 When the augmented reality device is encapsulated in the transparent body of the contact lens, Figures 1 to 3 or Figure 6 Cross-section of a contact lens. DETAILED DESCRIPTION

[0039] Reference Figure 1 , an augmented reality contact lens 100 according to the present invention will now be described.

[0040] Contact lens 100 is designed for use with an eye 104, which has an optical axis AO and a visual axis AV that intersect at point O. Eye 104 itself primarily comprises a cornea 106, which takes the form of a spherical cap at its interface with the surrounding air. Eye 104 also includes an iris 122, punctured at its center by a circular opening called a pupil 123, through which light travels. Iris 122 expands or contracts depending on the intensity of luminous light. Eye 104 also includes a lens 118, formed from a transparent, flexible disk of fibers, to focus incident light received through pupil 123. Intersection point O is generally located at the center of lens 118. Behind lens 118, on the other side of the ocular cavity 109, eye 104 also includes a retina 110, comprised of sensory cells including cones for daytime vision and rods for nighttime vision. Retina 110, extending from visual axis AV, has a central region called the fovea 111, where vision of fine detail is most precise. Therefore, the fovea 111 is eccentric by several degrees relative to the optical axis AO. The retina 110 also has an area around the fovea 111, which corresponds to peripheral vision and is called the parafovea 112. Figure 1 As shown, the cornea 106, the pupil of the iris 122, and the lens 118 are approximately centered about the optical axis AO.

[0041] The contact lens 100 firstly comprises a transparent body 102 which is designed to be placed on an eye 104 .

[0042] The transparent body 102 has a disk shape that is arched around a central axis AC and has a concave back surface 1004 and a convex front surface 1003. The back surface 1004 has a shape complementary to the cornea 106 so that Figure 1 The preferred position of the contact lens 100 is shown against the cornea 106. In this preferred position, the contact lens 100 is centered about the optical axis AO such that the central axis AC of the transparent body 102 is substantially coincident with the optical axis AO.

[0043] Because the transparent body 102 is in contact with the cornea 106, the transparent body is made of a biocompatible material, such as a silicone hydrogel or a Hydroxy Ethyl Methacrylate (HEMA) substrate, or any other suitable material as described in the article "Contact Lens Materials: A Materials Science Perspective" by C. Stephen, A. Musgrave, and F. Fang, published in the January 2019 issue of Material magazine, Volume 14, Issue 261.

[0044] The contact lens 100 also includes an augmented reality device 107 encapsulated within the transparent body 102 of the contact lens 100 .

[0045] Reference Figure 2 , the augmented reality device 107 will now be described in more detail.

[0046] The augmented reality device 107 has a general shape, for example, of a flat crown-shaped region, or alternatively, a flat annular region having its center located on the central axis AC of the transparent body 102. The augmented reality device 107 includes a transparent substrate 105 for guiding light, as described below. The transparent substrate 105 includes, for example, liquid crystal.

[0047] The augmented reality device 107 further includes at least one augmented reality module 108. Figure 2 In the example shown, the number of augmented reality modules 108 is eight and they are distributed in a star-shaped pattern such that each augmented reality module 108 is aligned along one branch of the star.

[0048] The augmented reality device 107 further includes a control module 10 of the augmented reality module 108, and the control module 10 is attached to the transparent substrate 105. Figure 5 The control module 10 is described in more detail.

[0049] Each augmented reality module 108 is designed to generate an image on retina 110 that is superimposed on the real scene captured by eye 104, once contact lens 100 is in the preferred contact lens position on eye 104. In the depicted example, the image is a warning sign intended to appear in peripheral vision. Therefore, in the depicted example, the image is preferably generated parafovea 112. Furthermore, in the depicted example, each augmented reality module 108 is designed to provide a different image on retina 110. Therefore, in this example, up to eight different images can be displayed parafovea 112.

[0050] The augmented reality modules 108 are similar to each other, so one of the augmented reality modules will now be described in more detail.

[0051] The augmented reality module 108 firstly comprises a light source 114 which is attached to the transparent substrate 105 and is designed to emit light into the transparent substrate 105 .

[0052] Preferably, light source 114 is point-shaped, i.e., it has a light output of less than 100 µm, and is monochromatic, i.e., it emits light with a single wavelength emission peak, for example, with a half-width of at most 100 nm. This peak is located in the visible spectrum, approximately 400-750 nm, and preferably in the green or red spectrum, 500-670 nm. Alternatively, this peak is within the sensitivity wavelength of the photoreceptors of retina 110, more specifically, the sensitivity wavelength of the parafoveal photoreceptors 112 (e.g., 420 nm for rods and 534 nm for cones).

[0053] More preferably, the light source 114 has a divergence of less than 40°.

[0054] For example, the light source 114 comprises a laser, and more specifically at least one vertical-cavity surface-emitting laser diode, known as a VCSEL (Vertical-Cavity Surface-Emitting Laser). Advantageously, this type of light source has reduced dimensions, thus enabling the thickness of the contact lens 100 to be significantly reduced compared to the pixel matrices used in contact lenses of the prior art.

[0055] Augmented reality module 108 also includes a hologram 116, which is attached to transparent substrate 105 and designed to receive light from light source 114 and transmit it in the direction of eye 104, more specifically, through pupil 123 toward lens 118. Hologram 116 is a diffractive optical element, often referred to by the abbreviation DOE (Diffractive Optical Element). Hologram 116 is designed to diffract received light in the direction of eye 104 into a holographic image. This transformation is based on the optical phenomenon of diffraction, resulting in the diffracted light (holographic image) corresponding to, for example, a Fresnel transform or spatial Fourier transform of the final image to be imaged on retina 110. The design of the hologram preferably takes into account the tissue through which the light passes.

[0056] Thus, generally, the hologram 116 is configured to generate and project a desired final image onto the retina of the eye. In particular, the structure of the hologram defines the image. As described above, in some embodiments, the hologram can be configured to provide an inverse spatial Fourier transform of the final image to be projected onto the retina. In other embodiments, the hologram can be configured to implement additional optical functions, such as a Fresnel transform of the desired image.

[0057] In practice, hologram 116 comprises, for example, a blade of a transparent substrate of constant thickness, such as a glass plate, with cross-sectional microstructures or nanostructures on or within the blade configured to diffract an incident wavefront to generate a holographic image. These microstructures or nanostructures form a diffraction pattern. Alternatively, hologram 116 can operate as a reflective mirror, rather than in a transparent form.

[0058] For example, when the contact lens 100 is in the preferred contact lens position on the eye 104, a hologram 116 is obtained by depositing a photosensitive resin layer (e.g., type S1813) with a thickness of approximately 1.2 μm on the surface of the transparent body 102 in a region located at the end facing the pupil 123. Then, while the region surrounding the hologram 116 is fully exposed, a multi-level phase profile is photoetched into the resin. In a development step, the hologram 116 is inscribed into the resin layer, and the resin surrounding the hologram 116 is removed. The resulting hologram 116 has, for example, a resolution of approximately 750 nm and an engraving depth of approximately 1000 nm.

[0059] In order not to interfere with the central vision of the eye 104, the contact lens 100 preferably has a central area 120 formed only by the transparent body 102. When the transparent body is arranged on the eye 104 in the preferred position of the transparent body, this central area 120 is located on the optical axis AO in front of the pupil 123. Due to this central area 120, the pupil 123 is at least partially cleared of any elements that may reduce vision.

[0060] In particular, in the depicted example, the holograms 116 of the various augmented reality modules 108 are arranged in an annular area surrounding a central region 120. The maximum radius of this hologram crown is equal to the pupil (the maximum opening of the pupil, for example, 8 mm), and the minimum radius of the hologram crown leaves the central region of the pupil 123 free (for example, 2 mm), meaning that the pupil 123 can vary between these two values. Thus, in the depicted example, each hologram 116 has a radial dimension of at most 6 mm. If the pupil 123 were equal to the minimum radius of the hologram crown, no projection onto the retina 110 would be possible. Otherwise, even if the hologram 116 were only partially clear, an image would still be formed on the retina, because in this case, the holographic image of at least a portion of the pattern of the hologram 116 would still pass through the pupil 123. Due to the design of the hologram, this is sufficient to allow the final image to appear on the retina 110, but in return, the illumination level of the retina 110 would be reduced. In practice, the hologram 116 includes a periodic pattern such that if a portion of the hologram is obscured by the pupil 123, the hologram 116 is able to generate a holographic image that is still imaged onto the retina 110 via the lens 118, but the holographic image has reduced intensity and possibly reduced resolution compared to the case where the hologram 116 is not partially obscured by the pupil 123.

[0061] Reference Figure 3 Preferably, the central region 120 has a diameter d of at least 3 mm around the central axis AC to properly clear the pupil 123.

[0062] In order to prevent a portion of the light emitted by the light source 114 from leaving the transparent substrate 105 before reaching the hologram 116, the contact lens 100 further comprises a layer of reflective material 124 which at least partially covers the surface of the transparent substrate 105 except for the central region 120 so as not to obscure the central vision of the eye 104. Thus, the transparent substrate 105 and the layer of reflective material 124 form a light guide which directs the light from the light source 114 to the associated hologram 116.

[0063] Outside the central area 120, the reflective material layer 124 does not necessarily extend over the entire remaining surface of the transparent substrate 105. For example, the edge 1001 of the transparent substrate 105 may be free of any reflective material layer 124.

[0064] For example, the reflective material layer 124 comprises gold. In this case, it is advantageously possible to produce a very thin reflective layer of the order of a few nanometers by means of a photolithographic technique, for example of the "lift-off" type.

[0065] Alternatively, the reflective material layer 124 comprises aluminum or silver, which advantageously enables the strength and reflectivity factor of the reflective material layer 124 to be enhanced.

[0066] like Figure 3 As shown, the light source 114 and the hologram 116 are arranged within the transparent substrate 105 so as to be partially surrounded by and flush with the transparent substrate 105. Alternatively, one or both of the light source and the hologram may be completely surrounded by the transparent substrate 105.

[0067] Reference Figure 4 , an example of an embodiment of the control module 10 will now be described in more detail.

[0068] The control module 10 first includes a power supply 130 , such as a battery. Specifically, the power supply 130 is designed to feed the light source 114 of each augmented reality module 108 .

[0069] The control module 10 also comprises means for charging, for example, an inductive battery 132 .

[0070] The control module 10 also comprises a radio receiver Rx, for example Wi-Fi, designed to receive commands C.

[0071] The contact lens 100 further includes a selection activation module 136 for selectively activating the augmented reality module 108 based on the received command C. For example, the selection activation module 136 includes a switch 1361 connected between the battery and the light source 114 .

[0072] Reference Figure 5 , an example of the augmented reality method 500 will now be described.

[0073] Specifically, the method describes the use of one of the augmented reality modules 108 , but is applicable to each of the augmented reality modules 108 .

[0074] During step E1, the contact lens 100 is placed on the eye 104 so that the transparent body 102, more precisely the back surface 1004 of the transparent body, is placed on the cornea 106, in a manner such that Figure 1 and Figure 3 Preferred position shown.

[0075] Assume that initially, the augmented reality module 108 is not activated, and thus the augmented reality module does not provide a holographic image.

[0076] During a step E2 , the selection and activation module 136 receives, via the receiver Rx, a command C indicating the activation of the augmented reality module 108 .

[0077] During step E3 , in response to instruction C, the selection activation module 136 activates the augmented reality module 108 indicated in instruction C to provide a holographic image. In the example described, the switch 1361 , initially in the open position, is closed, causing the feed source 130 to feed the light source 114 .

[0078] During a step E4 , the light source 114 , now fed, emits light which is guided into the interior of the transparent body 102 by optical reflections between the layers of reflective material 124 .

[0079] During a step E5 , the hologram 116 associated with this light source 114 receives the guided light.

[0080] During a step E7 , the hologram 116 diffracts the received light so as to form an image sent in the direction of the eye 104 , more precisely in the direction of the pupil 123 .

[0081] exist Figure 3 In FIG, the luminous rays are represented as dotted lines in order to illustrate the path of the light in a simplified manner. In practice, a plurality of luminous rays are emitted by the light source 114 in order to form a luminous beam.

[0082] During a step E9 , the crystal 118 receives the waves diffracted by the hologram and participates in the reconstruction of the final image (corresponding to this holographic image) on the retina 110 .

[0083] Thus, a final image of the virtual object appears on the retina 110 where it is superimposed on the real scene captured by the eye 104. In the depicted example, optical reconstruction occurs in the parafovea 112 so that the final image appears in the peripheral vision of the eye 104.

[0084] Specifically, the image of the virtual object is projected about 10° from the fovea 111 (or equivalently, from the optical axis AO) relative to point O to avoid interfering with central vision, which corresponds to 12°-15° from the optical axis AO relative to point O. Preferably, the final image extends over a field of view of at most 2° (about four full moons), which corresponds to a length of about 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 microns to be perceived.

[0085] During a step E10 , the selection activation module 136 receives, via the receiver Rx, an instruction C indicating the deactivation of the augmented reality module 108 .

[0086] During step E11 , in response to instruction C, the selection activation module 136 deactivates the augmented reality module 108 indicated in instruction C, so that the augmented reality module no longer provides holographic images. In the example described, the switch 1361 is opened so that the feed source 130 no longer feeds the light source 114 and the light source stops emitting light.

[0087] Reference Figure 6, a contact lens 100 ′ according to an alternative embodiment of the present invention will now be described.

[0088] This variant of the embodiment differs essentially from the previous embodiment described above in the number of augmented reality modules (four instead of eight) and in the way in which the holograms sent in the direction of the eyes are selectively activated and deactivated.

[0089] According to this embodiment, light source 114 continuously emits light, and for each hologram 116, selective activation module 136 includes a refractive index changing device designed to change the refractive index of transparent substrate 105, for example, through liquid crystal contained within the transparent substrate. In practice, the liquid crystal is a birefringent electro-optical element whose refractive index is altered by an applied electric field. Once the refractive index is altered, the guiding conditions (e.g., the deflection angle) are modified so that hologram 116 is no longer illuminated, thereby providing a holographic image.

[0090] For example, the refractive index changing device includes at least one pair of electrodes designed to generate an electric field that changes the refractive index in at least one direction. In the described example, these electrodes are made of a plate of reflective material. Specifically, the reflective material includes a large annular region 124A on the front surface of the transparent substrate 105 and a small annular region 124B on the back surface of the transparent substrate 105. The small annular region 124B is divided into four parts 142A, 142B, 144A, and 144B that are electrically isolated from each other and connected to the control device 10'. Each pair of opposing parts forms a pair of electrodes.

[0091] Therefore, upon receiving the instruction C, the selection activation module 136 is designed to apply a voltage between the electrodes associated with the augmented reality module 108 to which the instruction C relates, so as to change the refractive index of the transparent substrate 105 extending between the electrodes. As a result, the hologram 116 of the augmented reality module 108 is no longer sufficiently illuminated to provide a holographic image.

[0092] Reference Figure 7 The transparent body 102 includes, for example, a base 102A having a housing 702 for receiving the 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 ).

[0093] As can be readily understood from the preceding description, when a hologram is illuminated by a light source, it is the hologram that generates the holographic image. In this case, the light source provides neutral light (e.g., a beam of uniform intensity) that does not contain any image or image information. Therefore, a hologram illuminated solely by the light source can generate an image in the direction of the eye. Compared to existing technologies, no screen or pixel matrix is ​​required. Specifically, the light source can be as simple as a single point-like light source to illuminate the hologram.

[0094] It is clear that contact lenses for augmented reality such as those described above make it possible to superimpose an image on the retina of the eye in a compact and simple manner onto the real scene captured by the eye.

[0095] It should also be noted that the present invention is not limited to the above-described embodiments. For those skilled in the art, various modifications can indeed be made to the above-described embodiments based on the teachings just disclosed.

[0096] In particular, the properties and emission characteristics of the light source can be adjusted according to the target application.

[0097] Furthermore, an optical element, such as a Fresnel lens, may be arranged between the light source 114 and the hologram 116 in order to shape the light beam to improve imaging conditions.

[0098] In the foregoing detailed description of the invention, the terms used should not be construed to limit the invention to the embodiments disclosed herein, but should be construed to include all equivalents that can be anticipated by those skilled in the art by applying their general knowledge to the implementation of the just disclosed teachings.

Claims

1. A contact lens (100; 100') for augmented reality, comprising: - a transparent body (102) designed to be arranged on the eye (104); - a plurality of augmented reality modules (108), each of said augmented reality modules comprising: a light source (114) attached to the transparent body (102) and designed to emit light into the transparent body (102); an optical element attached to the transparent body and designed to receive light from the light source (114) and to send the light in the direction of the eye (104); Characterized in that the light source (114) is suitable for emitting light received by the optical element without comprising an image, and the optical element is a hologram designed to diffract the received light so as to generate a holographic image in the direction of the eye (104), the contact lens having a central area (120) consisting only of the transparent body (102), Each module (108) is designed to provide a final image on the retina (110) that is different from the final images of the other modules, The holograms of the augmented reality modules are arranged in an annular area surrounding the central area.

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

3. The contact lens (100; 100') according to claim 1, further comprising a light guide designed to guide light from the light source (114) to the hologram (116).

4. The contact lens (100; 100') according to claim 3, wherein The light guide comprises a transparent substrate (105) and a layer (124) of reflective material, the layer of reflective material covering the outer surface of the transparent substrate (105).

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

6. The contact lens (100; 100') according to any one of claims 1 to 5, comprising: - a radio receiver (Rx) attached to the transparent body (102) and designed to receive commands (C); and - a selection and activation module, the selection and activation module is used to selectively activate each of the augmented reality modules (108) according to the received instruction (C).

7. The contact lens (100; 100') according to any one of claims 3 to 5, comprising: - a radio receiver (Rx) attached to the transparent body (102) and designed to receive commands (C); and - a selection and activation module, the selection and activation module being used to selectively activate each of the augmented reality modules (108) according to a received instruction (C); Therein, the selective activation module comprises a refractive index changing device (140) designed to change the refractive index of the light guide to change the illumination of the hologram (116) so that the hologram stops providing the holographic image.

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

9. An augmented reality method (500), the augmented reality method comprising: - providing a contact lens (100) according to claim 1; - placing ( E1 ) the transparent body ( 102 ) of the contact lens ( 100 ) on the eye ( 104 ); - emitting (E4) light from a light source (114) attached to the transparent body (102) into the transparent body (102); and - receiving (E5) said light by an optical element attached to said transparent body (102) and sending (E7) said light through said optical element in the direction of said eye (104).

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