VIEWING APPARATUS AND METHOD FOR PROJECTING A LIGHT SIGNAL

Abstract

The present invention concerns a viewing apparatus comprising: a first optical line comprising: a projecting system adapted to project a light signal on a first area of the retina of an eye of a wearer of the viewing apparatus, a light signal generator generating the light signal to be projected, and a waveguide comprising an input coupler and an exit coupler, the waveguide being adapted to convey light from the input couple to the exit coupler, and optionally a second optical line comprising an optical system adapted to project a light signal of the environment on a second area of the retina of the eye of the wearer, the optical system comprising a part of the waveguide.

Claims

1-17. (canceled)

18. Viewing apparatus comprising: a first optical line comprising: a projecting system adapted to project a first light signal on a first area of the retina of an eye of a wearer of the viewing apparatus, a light signal generator generating the first light signal to be projected, and a waveguide comprising an input coupler and an exit coupler, the waveguide being adapted to convey light from the input coupler to the exit coupler.

19. Viewing apparatus according to claim 18, wherein the viewing apparatus further comprises a second optical line comprising an optical system adapted to project a light signal of the environment on a second area of the retina of the eye of the wearer.

20. Viewing apparatus according to claim 18, wherein the waveguide is translucent, preferably transparent.

21. Viewing apparatus according to 18, wherein the light signal generator comprises a total internal reflection prism adapted to steer an incident light beam with an angle,

22. Viewing apparatus according to claim 21, wherein the angle is comprised between 20° and 40°.

23. Viewing apparatus according to claim 19, wherein the two optical lines are arranged so that the intersection between the first area and the second area is void.

24. Viewing apparatus according to claim 19, wherein the two optical lines are arranged so that the second area surrounds the first area.

25. Viewing apparatus according to claim 19, wherein a main direction of light conveyance is defined for the waveguide and wherein the second optical line) and the waveguide (24) are arranged so that the light in the second optical line propagates along a general direction which is perpendicular to the main direction of light conveyance of the waveguide.

26. Viewing apparatus according to claim 18, wherein the first optical line is a folded line.

27. Viewing apparatus according to claim 19, wherein the second optical line is an unfolded line.

28. Viewing apparatus according to claim 27, wherein the light signal generator comprises a light source and the first optical line a collimating lens, the total internal reflection prism, a digital micromirror device and a projecting lens.

29. Viewing apparatus according to claim 18, wherein the light signal generator comprises a light source, the light source being at least one of a fibered source and an electroluminescent diode.

30. Viewing apparatus according to claim 18, wherein the viewing apparatus is an apparatus for optogenetics uses.

31. Viewing apparatus according to claim 18, wherein the viewing apparatus is a virtual reality apparatus.

32. Viewing apparatus according to claim 19, wherein the second optical line is parallel to the gaze direction of the eye of the wearer.

33. Viewing apparatus according to claim 18, wherein the field of view of the projecting system extends between 15° and 25° along a first direction and between 25° and 35° along a second direction perpendicular to the first direction.

34. A method for projecting a light signal in an eye of the wearer of a viewing apparatus comprising a first optical line comprising: a projecting system adapted to project a first light signal on a first area of the retina of an eye of a wearer of the viewing apparatus, a light signal generator generating the first light signal to be projected, and a waveguide comprising an input coupler and an exit coupler, the waveguide being adapted to convey light from the input coupler to the exit coupler.

35. Method according to claim 34, wherein the viewing apparatus further comprises a second optical line comprising an optical system adapted to project a light signal of the environment on a second area of the retina of the eye of the wearer, the method comprising simultaneously a step of projecting a light signal with the first optical line and a step of projecting an environment light signal with the second optical line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The invention will be better understood on the basis of the following description which is given in correspondence with the annexed figures and as an illustrative example, without restricting the object of the invention. In the annexed figures:

[0046] FIG. 1 shows schematically an example of viewing apparatus in a context of use by a wearer, and

[0047] FIG. 2 is a detailed view in section of the viewing apparatus of FIG. 1.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0048] A viewing apparatus 10, a wearer 12 and a part of the environment 14 of the wearer 12 are represented on FIG. 1. The part of the environment comprises trees 14A.

[0049] A viewing apparatus 10 is an apparatus used by the wearer 12 of said apparatus 10 for viewing the part 14 of the environment.

[0050] An example of specific viewing apparatus 10 is further detailed on FIG. 2.

[0051] A first direction parallel to axis X and called “first direction X” is defined. A second direction parallel to axis Y and perpendicular to axis X is defined and called “second direction Y”. A third direction parallel to axis Z and perpendicular to axis X and Y is defined, and called “third direction Z”.

[0052] The viewing apparatus 10 comprises two optical lines, a first optical line 16 and a second optical line 18.

[0053] An optical line is the set of elements along the optical line that link a source of light signal to the eye 19 of the wearer 12.

[0054] According to preferred embodiments of the invention, said light signal is an image.

[0055] The first optical line 16 is a folded line.

[0056] It is understood by “folding line” that elements are arranged in such a manner that a light beam along the first optical path has a polygonal chain 16A.

[0057] The first optical line 16 comprises a light signal generator 20, a projecting system 22, and a waveguide 24.

[0058] The light signal generator 20 is adapted to generate the first light signal to be projected.

[0059] The light signal generator 20 comprises a light source 26, a collimating lens 28, a total internal reflection (TIR) prism 30 and a digital micromirror device (DMD) whose reference sign is 32.

[0060] In some cases, the wording DMD imager can be found for element 32.

[0061] According to the example of FIG. 2, the path of the light in the first optical line 16 follows the path of elements 26, 28, 30, 32, 30.

[0062] The light source 26 comprises a light-emitting element 34 adapted to generate light.

[0063] The generated light is selected according to the use of the viewing apparatus of the Invention. For example, in the case of the use of the viewing apparatus by a person equipped with a retina implant with photodiodes, the light-emitting element will be adapted so as to generate a light intensity that stimulates the photodiodes of the implant. Likewise, in the case of the use of the viewing apparatus by a person who has benefitted from optogenetic treatments, the light-emitting element will be adapted to provide a light intensity at wavelengths specific to this application, which stimulate the treated zone.

[0064] The light-emitting element 34 is therefore chosen with in particular a spectral range and/or an intensity corresponding to the application envisaged. The light-emitting element 34 may for example be a laser source or a non-coherent light source.

[0065] According to preferred embodiment, the light-emitting element 34 is a non-coherent light source.

[0066] For example, the light-emitted element 34 comprises an electroluminescent diode, more particularly a light-emitting diode (LED) or LED derivatives (e.g. OLED).

[0067] In the specific example, the light source 26 also comprises a light fiber 36 to convey light to the light emitting element 34.

[0068] More precisely and as a particular example, the light source 26 is an electroluminescent diode (not shown) which is followed by an optical fiber 36.

[0069] In other words, the light source 26 is a fibered LED.

[0070] According to preferred embodiment, the light-emitting element 34 is adapted to provide a light at wavelength able to depolarize cell that includes a light-activated ion channel polypeptide. Exemplary wavelengths of light that may be used to depolarize a cell expressing a light-activated ion channel polypeptide, include wavelengths from at least about 365 nm, 385 nm, 405 nm, 425 nm, 445 nm, 465 nm, 485 nm, 505 nm, 525 nm, 545 nm, 565 nm, 585 nm; 590 nm, 605 nm, 625 nm, 645 nm, 665 nm, 685 nm; and 700 nm, including all wavelengths therebetween. In preferred embodiments, light-emitting element 34 is adapted to provide a light intensity at wavelengths in a range of 365 nm to 700 nm, preferably ranging from 530 nm to 640 nm, preferably ranging from 580 nm to 630 nm, preferably ranging from 530 nm to 610 nm, and more particularly the light wavelength is about 595 nm.

[0071] As used herein, the term “about” when used in conjunction with numerical amount, means plus or minus 10% of that numerical amount.

[0072] The collimating lens 28 is adapted to collimate incident light beams 31 coming from the light source 26.

[0073] The light beams 31 emerging from the collimating lens 28 are substantially parallel to each other along the first direction X.

[0074] For example, the collimating lens 28 has a focal length selected in the range of 2 millimeters (mm) and 20 mm, more specifically in the range of 3 mm and 18 mm, even more particularly the collimating lens 28 has a focal length of about 5.9 mm.

[0075] A total internal reflection prism is often named TIR prism by using the acronym of Total Internal Reflection. TIR prisms are well known in the art.

[0076] The TIR prism 30 is adapted to steer an incident light 31 beam with an angle α, named in what follows the “steering angle α”.

[0077] The TIR prism 30 comprises an input face 30A, an output face 30B, a reflection face 30C, an incident prism 30.sub.1 and an output prism 30.sub.2.

[0078] The incident face 30A receives the incident light beam.

[0079] The light beam outputs the TIR prism 30 by the output face 30B.

[0080] The input face 30A and the output face 30B are for example perpendicular to each other.

[0081] The steering angle α is the angle between the light beam emerging from prism 30.sub.1 and the normal to the digital micromirror device 32.

[0082] The steering angle α is for example comprised between 20° and 40°.

[0083] By definition, α comprised between the values A and B means that, on the one hand, α is superior or equal to the value A and that a is inferior or equal to the value B.

[0084] In a specific embodiment, the steering angle α is equal to 24°.

[0085] The incident face 30A belongs to the input prism 30.sub.1 and the output face 30B belongs to the output prism 30.sub.2.

[0086] The reflection face 30C belongs to the input prism 30.sub.1.

[0087] Input prism 30.sub.1 and an output prism 30.sub.2 have complementary faces.

[0088] A tiny gap 40 is defined between the input prism 30.sub.1 and the output prism 30.sub.2. The tiny gap 40 is defined between their complementary faces.

[0089] A digital micromirror device 32 is often named DMD by using the acronym of Digital Micromirror Device.

[0090] DMD are well known in the art. DMD comprises an array (e.g. 608×684 array or 912×1140 array) of mirrors that can switch regularly (e.g. every 0.35 millisecond (ms)) between two discrete angular positions named ON and OFF, with the ON position reflecting the incoming light towards the target. Processed events are encoded by setting the corresponding mirror ON.

[0091] The digital micromirror device 32 is arranged in the optical path of the light beam reflected by the reflected face 30C of the input prism 30.sub.1 and adapted to reflect at least a part of the light beam toward the output prism 30.sub.2.

[0092] A digital micromirror device 32 enables or disables a certain number of pixels in order to form the light signal to be projected.

[0093] The digital micromirror device 32 comprises a plurality of mirrors that forms arrays of micromirrors.

[0094] Each mirror has at least two positions.

[0095] In a first position, the mirror reflects light beams toward the output prism 30.sub.2 such that the light is transmitted to the output prism 30.sub.2 and emerges from the output face 30B.

[0096] In a second position, the mirror reflects light beams in such a way that no light is outputted from the output face 30B.

[0097] The projecting system 22 is adapted to project a first light signal on a first area 23 of the retina 19A of an eye 19 of the wearer 12 of the viewing apparatus 10.

[0098] In the example, the projecting system 22 is a projecting lens 42.

[0099] The field of view of the projecting system extends between 15° and 25° along a first direction and between 25° and 35° along a second direction perpendicular to the first direction.

[0100] The waveguide 24 comprises a body 24A, an input coupler 24B and an exit coupler 24C.

[0101] The waveguide 24 is adapted to convey light from the input coupler 24B to the exit coupler 24C.

[0102] According to preferred embodiment, all or part of the body 24A of the waveguide 24 is made from a translucent material.

[0103] In the following description, the term “translucent” refers to a light-transmitting body with a light transmission rate between 5% and 100%.

[0104] More preferably, all or part of the body 24A is made from a transparent material.

[0105] The term “transparent” refers to light-transmitting body with a light transmission rate greater than 95%, for example close to 100%. In particular, such a “transparent” body transmits light by refraction and through which objects are clearly visible.

[0106] Light in the waveguide 24 is composed of electromagnetic waves whose wavelength is between 500 nanometers (nm) and 700 nm.

[0107] Moreover, the body 24A of the waveguide is a parallelepiped.

[0108] In the example of FIG. 2, a main direction is defined for the waveguide 24 defined by the length of the body 24A of the waveguide 24. Such main direction is a main direction for light conveyance by the waveguide 24.

[0109] An inside face 24D and an exterior face 24E is defined for the body. The inside face 24D and the exterior face 24E are normal to the second direction Y.

[0110] The inside face 24D is intended to be directed toward the projector system 22 of the viewing apparatus and the eye 19 of the wearer when the viewing apparatus is worn.

[0111] The exterior face 24E is intended to be directed toward the part of the environment 14.

[0112] In the particular example of FIG. 2, the main direction is along the first direction X.

[0113] The input coupler 24B and the output coupler 24C are arranged on the inside face 24D of the body 24A.

[0114] For example, the input coupler 24B is arranged at an extremity of the inside face 24D and the output coupler 24C is arranged at the other extremity of the inside face 24D along the main direction.

[0115] The input coupler 24B is facing the projecting lens 42.

[0116] The input coupler 24B forms an incidence zone of the waveguide 24 whereby the light beams exiting the projector system 22 enters.

[0117] This input coupler 24B comprises a surface treatment of a part of the inside face 24D of the body 24A.

[0118] The input coupler 24B is made from a thin film in polymer.

[0119] By definition, a thin film is a film whose thickness is inferior to 10 micrometers (μm). By definition, an object is made in polymer when the content of the material of the object in polymer is superior or equal to 80%.

[0120] According to special embodiment, said polymer is silver halide.

[0121] The exit coupler 24C is facing the eye 19 of the wearer 12.

[0122] The exit coupler 24C forms an output zone of the waveguide 24.

[0123] This output coupler 24C comprises a surface treatment of a part of the inside face 24D of the body 24A.

[0124] The exit coupler 24C is made from a thin film in polymer.

[0125] The second optical line 18 is an unfolded line.

[0126] It is understood by unfolding line that the elements of the second optical line 18 are aligned such as a light beam along the second optical line 18 has a substantially straight path 18A compared to the path of the light beam along the first optical line 16.

[0127] In particular, the second optical line 18 is parallel to the gaze direction of the eye 19 of the wearer. For example, the second optical line is parallel to the second direction Y.

[0128] The second optical line 18 comprises an optical system 44 adapted to project/transmit a second light signal of the environment on a second area 46 of the retina 19A of the eye of the wearer.

[0129] According to special embodiment, the optical system 44 is part of the waveguide 24, named 25. It can further be independent from said waveguide 24. Alternatively, the second optical line 18 arrives directly from the environment to the eye of the wearer.

[0130] The limits of this part 25 of the waveguide 24 are defined by the optical field of view angle of the wearer 12.

[0131] More precisely, the part 25 is the intersection of the waveguide with the field of view angle of the wearer 12.

[0132] The part 25 comprises the output coupler 24C.

[0133] The second optical line 18 and the waveguide 24 are arranged so that the light in the second optical line 18 propagates along a general direction which is perpendicular to the main direction of the waveguide 24. For example, the general direction is along the second direction Y.

[0134] The two optical lines 16, 18 are arranged so that the intersection between the first area 23 and the second area 46 of the retina 19A is void. The space between the first and second areas 23, 46 is called “void area 48”.

[0135] Alternatively or in combination with the previous arrangements, the two optical lines 16, 18 are arranged so that the second area 46 surrounds the first area 23.

[0136] According to special embodiment, the viewing apparatus 10 comprises at least one lens to correct vision defects, such as for example eye glass lens. Such lens to correct vision defects are preferably located on optical line 16 between output coupler 24C and the eye of the wearer and/or optical line 18 before eye of the wearer.

[0137] According to special embodiment, the viewing apparatus 10 comprises at least one optical filter, for example colored optical filter. Such a filter can be located along the optical line 16 (for example between the collimating lens 28 and the total internal reflection prism 30, and/or between the total internal reflection prism 30 and the digital micromirror device 32, and/or between the DMD and the projecting lens 42, and/or between the projecting lens and the waveguide 24) and/or along the optical line 18.

[0138] The operating of the viewing apparatus 10 is now described in reference to a method for projecting light signals on an eye of the wearer.

[0139] According to special embodiment, the viewing apparatus 10 is in the form of a pair of spectacles.

[0140] The method comprises a step of providing, a step of positioning and two steps of projecting.

[0141] During the step of providing, the viewing apparatus 10 is provided to the wearer 12.

[0142] As a specific example, an eye professional gives the viewing apparatus 10 to the wearer 12.

[0143] At the step of positioning, the wearer takes the viewing apparatus and positions it on his head in front of his eyes.

[0144] For instance, when the viewing apparatus 10 comprises a fixing band, the wearer 12 uses the fixing band to have the viewing apparatus 10 fixed on his head.

[0145] The two steps of projecting are achieved simultaneously.

[0146] According to the first step of projecting, a first light signal is projected with the first optical line 16 on the first area 23 of the retina 19A.

[0147] The first light signal to be projected is generated by the light signal generator 20.

[0148] More precisely, incident light beams 31 generated from the fibered LED 26 are transmitted to the TIR prism 30.

[0149] Light beams 31 are reflected by the reflection face 30C of the input prism 30 toward the micromirror device 32.

[0150] In function of the position of the micromirrors of the micromirror device 32, the light beam is split into a selected part, reproducing the light signal to be projected, and a discarded part.

[0151] The selected part is projected through the output prism 30.sub.2.

[0152] The light beam emerging from the output face 30B is transmitted to the projecting lens 42.

[0153] The light beam exiting the projected lens 42 is transmitted to the waveguide 24 through the input coupler 24B.

[0154] The body 24A of the waveguide 24 conveys the light beam to the output coupler 24C whereby the light beam is exiting the waveguide 24.

[0155] The light beam exiting the output coupler is projected in the first area 23 of the retina of the wearer 12.

[0156] Simultaneously, the method comprises the second step of projecting.

[0157] According to the second step of projecting, an environment light signal (i.e. second light signal) is projected with the second optical line 18.

[0158] Light beams from the environment passes through the body 24A of the waveguide 24 and reach the second area 46 of the retina 19A.

[0159] The light beams from the environment are transmitted into the body 24A by the exterior face 24E, cross the body 24A and come out the waveguide by the output coupler 24C and are projected onto the second area 46 of the retina 19A.

[0160] The waveguide 24 will keep the peripheral vision of the patient intact while enabling the light signal generator 20 to be placed away from the wearer's visual field.

[0161] Using a fibered LED 26 together with a reflection prism 30 also makes it possible to have the LED away from the projecting system thus reducing heating problems for the wearer 12.

[0162] Moreover the second light signal projected with the second optical line 18 completes light signal projected with the first optical line for rebuilding a part of the environment.

[0163] Moreover, thanks to the second optical line 18, it is ensured that the second light signal is projected on a second area 46 of the retina 19A which does not have any overlap area with the first area 23 of the retina 19A.

[0164] Moreover, the viewing apparatus 10 of the invention enables to obtain a device independent of pupil size especially if pupil size is above 3 millimeters (mm) in diameter.

[0165] The viewing apparatus 10 also allows delivering the necessary irradiance to the retina 19A of the wearer 12.

[0166] The viewing apparatus 10 is also compact. In particular, as the first optical line 16 is a folded line, it is possible to bring the elements of the first optical line 16 closer to the waveguide 24.

[0167] Thus the dimension of the viewing apparatus along the second direction is reduced compared to known viewing apparatus.

[0168] Such viewing apparatus also provides the wearer with a field of view of 20°×30° thanks to the use of the whole apparatus 10 and notably the TIR prism 30 with the digital micromirror device 32

[0169] The viewing apparatus 10 does not obscure the patient's visual field.

[0170] According to a specific embodiment, the projecting system (22) and/or the light signal generator (20) are mounted on the frame of a pair of spectacles.

[0171] The viewing apparatus 10 may be used in the field of vision restoration using vision prostheses such as retinal implants.

[0172] According to a specific embodiment, the viewing apparatus 10 is an apparatus adapted for optogenetics.

[0173] The apparatus 10 defined above may be used for the subjects (i.e. wearer) suffering of photoreceptor loss or degeneration, such as in case of retinitis pigmentosa (RP) or macular degeneration (MD). As mentioned above, these affections diminish visual acuity, diminishes light sensitivity, or result in blindness of a part of the field of view of the subject.

[0174] As explained above, some therapies consist in stimulating transfected cells of the retina and/or retinal implants with a light beam.

[0175] The first area 23 of the retina on which the light signal with the first optical line 16 is intended to be projected comprise cells, more specifically retinal cells, that have been genetically modified for expressing light-gated ion channel protein for optogenetic therapy.

[0176] According to special embodiment, said light-gated ion channel protein is chosen in the group consisting of Chrimson, ChrimsonR, (WO2013/71231), ChrimsonR-tdT (WO2017/187272), Catch, Channelrhodopsin (US20140121265, U.S. Pat. No. 8,906,360), and melanopsin and derivatives thereof.

[0177] The first area 23 of the retina on which the light signal with the first optical line 16 is intended to be projected comprises retinal implant having to be stimulated.

[0178] The area of the retina is stimulated by a light beam reproducing light signal, more specifically an image, of the environment.

[0179] The projected light signal rebuilds the lost field of view due to the photoreceptor loss or degeneration in function of the gaze direction of the subject.

[0180] The light beam obtained with the first optical line and stimulating the parts of the retina is obtained by the method explained above.

[0181] In the detailed embodiment, the environment light signal, more specifically the image, projected with the second optical line 18 corresponds to the part of the environment that complete the light signal, more specifically the image, projected with the first line in such a way that the wearer sees a rebuilt light signal, more specifically the image, of the environment.

[0182] Moreover, the first area 23 of the retina is stimulated with the required light characteristics independent of the pupil size.

[0183] In such case, it is to be noted that thresholds of light intensity (maximum and minimum) are given by phototoxicity standards and are further analyzed in literature relevant to ophthalmology or to the application of light stimulation for an optogenetic therapy (Yan et al. 2016; Delori, Webb, and Sliney 2007; Sliney et al. 2005). For example, for a light with a wavelength of 595 nm, [0184] the maximum light intensity at the retina is 7 mW/mm.sup.2 (ISO 15004-2 2007; ISO 62471 2006), and [0185] At the cornea (anterior segment), the maximum light intensity is 32 mW over any 1 mm diameter disc (ISO 15004-2 2007).

[0186] In addition, the retinal radiant exposure limit when taking into account the luminance dose restriction is 6.6 J.Math.cm.sup.−2 over 48 hours (luminance dose restriction, ANSI Z136.1 2014).

[0187] According to another particular example, the viewing apparatus is adapted for a virtual reality apparatus. Head-Mounted displays are used for example used for augmented reality, for virtual reality or for movie display.

[0188] In such case, the light signal projected with the second optical line 18 generally has no specific link with the environment.

[0189] The viewing apparatus and the method disclosed in relation to the viewing apparatus 10 can be used for virtual reality or optogenetic applications.