Compact optical device for wide fields of view

Abstract

The invention relates to an optical device (1) comprising an optical axis (2) for projecting a real and / or virtual image of a real and / or virtual object (3) through an area called the exit pupil (4) arranged opposite to the real and / or virtual object (3), wherein at least a first lens (5) is arranged between the area called the exit pupil (4) and the real object (3) and / or the light rays of the virtual object (3), said first lens (5) comprising an optical center (51) arranged substantially on the optical axis (2) of the optical device (1), characterized in that the first lens (5) comprises a first surface (52) comprising a first area (521) at least partially structured, said first surface (52) comprising a central portion (522) and a peripheral portion (523),a second surface (53) opposite the first (52) comprising at least one second structured zone (531) and a second lens (6) comprising a surface (61) comprising at least one structured zone (611). Figure to be published with the abbreviation: Fig. 1,

Description

Title of the invention: Compact optical device for wide fields of vision

[0001] The invention relates to the technical field of optical devices, more particularly to optical devices enabling a wide field of vision. Similarly, the invention relates to an image diffusion system comprising said optical device.

[0002] An ocular lens used in wide-field optical devices is a lens or group of lenses located at the end of a human or electronic eye of an optical instrument.

[0003] Ocular lenses are thus found in various applications such as science, leisure, defense, sports, aeronautics, and the automotive industry. Ocular lenses are used in various optical systems such as image collimators, image magnifiers, and binocular magnifiers. Furthermore, these optical systems can be fixed, such as telescopes, microscopes, and head-up displays, or handheld, such as binoculars, monoculars, night vision goggles, observation glasses, or shooting glasses. They can also be worn, or used as head-up displays, near the eye, mounted on the head, for extended reality displays such as virtual, mixed, or augmented reality, or for video displays such as video glasses.

[0004] Generally, for this type of optical device comprising such ocular lenses, the fields of vision are between 45° and 60°, those of wide ocular lenses between 60° and 80° and those of ultrawide ocular lenses between 80° and 130°.

[0005] Thus, very wide field-of-view ocular lenses are currently used particularly in the fields of astronomical observation or wearable displays. However, such ocular lenses can be bulky and heavy, due to their thickness at the center, their optical back focus, and / or their diameter.

[0006] Thus, there is a real need to reduce the size of these devices including these ocular lenses, particularly for extended reality headsets.

[0007] Consequently, numerous efforts have been made to miniaturize and lighten wearable extended reality displays. These efforts have led to the development of more compact and lighter ocular architectures, surfaces, and components for ever-wider fields of view, such as ocular lenses slightly inclined relative to the axis of vision, by approximately 5°, and eyepieces composed of a... two lenses having in their architecture one or two Fresnel surfaces and / or a double pancake reflection, in order to meet the requirements of an ultra-wide field of vision.

[0008] Similarly, and in order to increase the compactness and field of these architectures, the architectures may also include holographic, diffractive or meta-optical surfaces.

[0009] In order to get closer to the human field of vision, in other words a larger field of vision that can reach 150° to 220° horizontally, efforts are being made to develop optical architectures with a wider field of vision than ultra-wide field of vision ocular lenses, all while being compact and lightweight, particularly in the field of wearable lenses, by tilting the lenses of the optical device more strongly relative to the main axis of vision of the receiver, on the order of 10° to 25°, and by using curved screens and / or lenses or even optical assemblies of several imaging paths.

[0010] However, the solutions provided are mediocre in terms of compactness, weight, field of view, and image quality or transmission. Furthermore, numerous parasitic effects are present in prior art solutions that attempt to provide an optical device with a very wide field of view, resulting in a poor quality of both real and virtual images.

[0011] Moreover, most of the architectures of these ocular lenses have a particular configuration which makes them unusable in applications other than wearable displays.

[0012] In order to resolve all these disadvantages, it is known to produce a so-called hybrid lens, comprising a central convex and smooth portion and an inclined outer portion comprising Fresnel grooves on two surfaces in order to obtain a strong deviation of the light rays of a screen positioned in an extended reality display.

[0013] However, these solutions are still not sufficient to achieve acceptable compactness on the market while having good image quality and a very wide field of view.

[0014] The invention therefore falls within this context and seeks to resolve all of the aforementioned drawbacks.

[0015] Thus, the invention seeks to provide an optical device offering a very wide field of view, while being compact, lightweight, and with improved image quality. Presentation of the invention

[0016] The invention relates to an optical device that provides a very wide field of vision, exceeding 180° and approaching 220°, while remaining compact and lightweight. in order to be able to create thin extended reality devices, for example as wide as a traditional pair of glasses.

[0017] For this purpose, an optical device has been developed comprising an optical axis, intended to project a real and / or virtual image of a real and / or virtual object, through an area called the exit pupil arranged opposite to the real and / or virtual object, in which at least a first lens is arranged between the area called the exit pupil and the real object and / or the light rays of the virtual object, said first lens includes an optical center arranged substantially on the optical axis of the optical device.

[0018] According to the invention, the first lens comprises a first surface including at least a first structured zone, preferably arranged at least in part over the entirety of a peripheral portion and a continuous slope of an average absolute value substantially less than 15°, over the entire radial height of the first surface, for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured parts of the first surface, said first surface includes a central portion traversed by the optical axis, a peripheral portion arranged on the periphery of the central portion including a substantially linear and inclined radial shape whose radial heights extend over the outer edges of the peripheral portion,defining a first maximum radial height on a first end and down to a minimum radial height in the cutting plane defined by the first maximum radial height and the optical axis on a second end of the peripheral portion, such that the error of an average inclination of the linear approximation between the first and second end, called average radial inclination, is substantially less than or equal to 10% of the angle formed by the normal to the optical axis and a straight line passing through a first maximum radial height and an intersection of the surface with the optical axis, called the opening angle of the first surface, said average radial inclination includes an angle of substantially between -1° and -70° with respect to a normal to the optical axis, when the optical device 1 is inscribed in an orthonormal frame whose center is defined by the intersection of the optical axis and the central portion of the first surface,said average radial inclination on the first radial heights is greater than at least, substantially, three times the opening angle of the first surface, a first maximum radial height such that a light ray passing through one of said first maximum radial heights forms substantially a minimum angle of 65° with the optical axis, an average radial inclination of the shape of the surface along its structured parts less than the average equivalent slope of the corresponding structured part, the first lens also includes a second surface, opposite to the first surface traversed by the optical axis of the , optical device, comprising at least a second structured zone, preferably arranged at least in part over the entirety of a peripheral portion, a continuous slope, the average radial inclination of the shape of the second surface along its structured parts being greater than the average equivalent slope of the corresponding structured part and, the optical device comprises at least a second lens, through which the optical axis of the optical device passes, said second lens comprising at least a first surface comprising at least a third zone or the first surface of the second lens is structured, preferably arranged at least in part over the entirety of a peripheral portion, said first surface of the second lens having a continuous slope.

[0019] Thus, such a lens having an overall shape substantially concavo-convex, meniscus, concave-plane or even concavo-concave, so that at least the slope of the peripheral portion of the first surface is inclined with respect to the optical axis and having a surface comprising structures for deviating the light rays passing through the lens makes it possible to obtain a lens offering a field of vision called wide field, that is to say greater than 130°, preferably greater than 180°.

[0020] The term "continuous slope" means that the slope along the first surface of the first lens is without discontinuity, particularly at the transition zones between the equivalent slope of the structures of the structured zone of the first surface and the slope of the first surface as such.

[0021] The term "radial height" means the distance from the optical axis of a point on a lens surface measured perpendicular to the optical axis.

[0022] By the terms "a substantially linear and inclined radial shape", we define the fact that the peripheral portion of the first surface of the first lens is inclined on the exteriors of the first surface.

[0023] The terms "maximum radial height" define, on a given cutting plane, the point on the first surface of the first lens furthest away measured perpendicular to the optical axis, in other words the point positioned on the outer end of the first surface.

[0024] The term "minimum radial height" means the point positioned on the peripheral portion of the first surface of the first lens closest to the optical axis, in other words the point of change between the portions of the first surface.

[0025] We speak of an average inclination on the peripheral portion of approximately -1° to -70°, by virtue of placing ourselves in an orthonormal coordinate system in which the optical axis is the x-axis and the normal to the optical axis is the y-axis, the center of the orthonormal coordinate system being the intersection of the optical axis and the central portion of the first surface.

[0026] In a preferred embodiment, the central portion of the first surface of the first lens extends substantially perpendicularly to the optical axis of the optical device.

[0027] In a particular embodiment in which the peripheral portion is devoid of an inflection point, the average slope of the central portion of the first surface of the first lens is greater than the average slope of the peripheral portion of the first surface.

[0028] In this same embodiment, the average radial inclination has an angle substantially between -20° and -70° with respect to a normal to the optical axis.

[0029] In a preferred embodiment, the first surface of the second lens is oriented towards the second surface of the first lens.

[0030] In another embodiment, the first surface of the second lens is oriented opposite to the second surface of the first lens.

[0031] In a particular embodiment, the second lens comprises a second surface opposite to the first comprising an area where the second surface is structured.

[0032] In a particular embodiment, the second lens may be of the double-reflecting pancake type and / or include a structured portion on the first and second surfaces.

[0033] In another embodiment, the double reflection pancake surfaces can be shared with other lenses.

[0034] Preferably, the first surface of the second lens and the second surface of the first lens are arranged so as to be brought close to each other at a point substantially positioned on the optical axis of the optical device.

[0035] In a particular embodiment, the first and second lenses are spaced one millimeter apart on the optical axis of the optical device.

[0036] Advantageously, having a second lens with a structured surface on a surface arranged opposite the second surface of the first lens allows for a symmetry of convergence powers between the second surface of the first lens and the first surface of the second lens, which reduces optical aberrations, resulting in improved image quality, while also allowing for increased convergence of light rays, thus providing an even larger field of view without deteriorating image quality or the compactness of the optical device.

[0037] In a preferred embodiment, the structured areas of the first surface and the second surface of the first lens and the structured areas of the first surface of the second lens are located partly and / or totally on a portion peripheral of each of the first lens and of the first surface of the second lens.

[0038] Thus, a strong deviation of the light rays from the object is obtained, which makes it possible to obtain a small object while having a compact optical device.

[0039] The peripheral portions of the second surface of the first lens and the first surface of the second lens are the areas crossed by light rays also passing through the peripheral portion of the first surface of the first lens.

[0040] In a particular embodiment, all the surfaces of all the lenses are structured.

[0041] In a particular embodiment, the optical device comprises at least a fourth structured area arranged on a first surface of a third lens, said first surface of the third lens comprising a continuous slope or arranged on a second surface opposite to the first surface of the second lens.

[0042] In a particular embodiment, the first surface of the third lens is arranged opposite the second surface of the second lens.

[0043] Preferably, the first surface of the third lens and the second surface of the second lens are arranged so as to be brought close to each other at a point substantially positioned on the optical axis of the optical device.

[0044] In a particular embodiment, the third and second lenses are spaced one millimeter apart on the optical axis of the optical device.

[0045] Thus, the presence of a fourth structured zone makes it possible to further reduce the size of the object in order to make a device comprising said optical device even more compact.

[0046] In a preferred embodiment, the optical device according to the invention comprises a fourth lens arranged between the first lens and the so-called exit pupil area, said fourth lens comprises at least a first unstructured surface and comprises a discontinuous slope over at least one radial height.

[0047] In a preferred embodiment, the first surface of the first lens comprises a continuous slope of an average absolute value substantially less than 7.5°, over the entire radial height of the first surface, for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured parts of the first surface.

[0048] In a particular embodiment, the first surface of the first lens comprises a continuous slope with an average absolute value substantially less than 5°, over the entire radial height of the first surface, for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured from the first surface.

[0049] In another preferred embodiment, the first surface of the first lens comprises a substantially flat slope over the entire radial height of the first surface, for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured parts of the first surface.

[0050] In a particular embodiment, the first surface of the first lens includes on the peripheral portion, at least partially structured, a maximum radial height such that a light ray passing through one of said maximum radial heights forms substantially a minimum angle of 80° with the optical axis and the average radial inclination on the radial heights of the peripheral part is greater than at least twice the opening angle of the first surface, in the orthonormal frame defined above.

[0051] In a preferred embodiment, the first surface of the first lens comprises on the peripheral portion, totally structured, a maximum radial height such that a light ray passing through one of said maximum radial heights forms substantially a minimum angle of 90° with the optical axis and average radial inclination on the radial heights of the peripheral part is greater than at least twice the opening angle of the first surface.

[0052] In a preferred embodiment, the first surface of the first lens includes on the peripheral portion, at least partially structured, a maximum radial height such that a light ray passing through one of said maximum radial heights forms substantially a minimum angle of 100° with the optical axis and with an average radial inclination on the radial heights is greater than at least twice an angle formed by the normal to the optical axis and a line connecting a maximum radial height and an intersection of the first surface with the optical axis, in the orthonormal frame defined above.

[0053] Preferably, the first surface of the first lens comprises a totally structured peripheral portion.

[0054] Preferably, the optical device according to the invention comprises a real and / or virtual object, said object includes a first end, defining a second maximum radial height of the object, said second maximum radial height being in the same transverse plane as the first maximum radial height and the optical axis, said optical device also includes a third maximum radial height arranged on one of the surfaces of the lenses of the optical device, said third maximum radial height may be different from the first maximum radial height, said third maximum radial height being greater than the second maximum radial height of the object.

[0055] The third maximum radial height is arranged in the same plane as the optical surfaces of the different surfaces of the different lenses.

[0056] The term "second maximum radial height of the object" means the point furthest perpendicularly from the optical axis belonging to the object.

[0057] The term "third maximum radial height" refers to the point furthest, perpendicularly from the optical axis, from the optical device. In other words, the maximum radial height among all surfaces along the path of the light ray having the longest deviation path.

[0058] Advantageously, the fact that the third maximum radial height is greater than a second maximum radial height of the object makes it possible to obtain a small screen, all while having an optical device that can deflect the light rays of the object efficiently and powerfully.

[0059] Furthermore, having a small screen size with a compact optical device makes it possible to obtain a more compact and lightweight extended reality system.

[0060] In a preferred embodiment, the optical device comprises a real and / or virtual object, said object comprises a first end, defining a second maximum radial height, of the object, said second maximum radial height being in the same transverse plane as the third maximum radial height and the optical axis, said second maximum radial height of the object is less than 0.7 times the first maximum radial height of the optical device.

[0061] In a preferred embodiment, the first surface of the first lens includes at least one inflection point, so that the inclination of the shape of the surface is reduced at higher radial heights, and whose average radial inclination of the peripheral portion of the first surface of the first lens on the high radial heights is greater than 1.5 times, to the opening angle of the first surface of the first lens, preferably the portion radially above the inflection point is devoid of structures, in the orthonormal frame defined above.

[0062] The terms "at higher radial heights" mean moving away from the optical axis, measured perpendicularly to the optical axis, in other words as one moves away from the optical axis, so the higher radial heights are the radial heights furthest from the optical axis of the optical device.

[0063] In a particular embodiment, the peripheral portion of a first surface of the first lens comprising an inflection point is structured over its entire surface.

[0064] Preferably, the first surface of the first lens includes at least one inflection point, so that the inclination of the surface shape is reduced at higher radial heights, and whose average radial inclination of the peri-portion pherical of the first surface of the first lens on high radial heights is greater than once the opening angle of the first surface of the first lens, preferably the portion radially superior to the point of inflection is devoid of structures.

[0065] More preferably, the first surface of the first lens includes at least one inflection point, so that the inclination of the shape of the surface is reduced at higher radial heights, and whose average radial inclination of the peripheral portion of the first surface of the first lens at the high radial heights is greater than 0.5 times, the opening angle of the first surface of the first lens.

[0066] In a preferred embodiment, the structures include draft surfaces, said draft surfaces of the set of structures of the structured surfaces of the lenses, are such that the latter deflect the so-called parasitic rays from the so-called exit pupil area.

[0067] The term "parasitic rays" refers to light rays generated by the surfaces of the surface structures or which may originate from the entire real and / or virtual object, whereby the light rays from points on the surface of the object are emitted in different directions and cause the presence of undesirable light such as ghost reflections, optical glare which interfere with the performance of the optical device according to the invention.

[0068] In other words, the light rays can be light rays resulting from the refraction of the object's outline, from the partial or total reflection of the object's outline on the internal surface of the outline's surface, from the partial or total reflection of the outline on the external surface of the outline, the light rays having a refraction slope after and before the refraction of the object's outline.

[0069] Advantageously, these shear surfaces deflect by themselves out of the so-called exit pupil area the stray light that the structured surface areas generate.

[0070] Preferably, in the invention, low draft angle values ​​are considered in order to maximize transmission and we take into account the unstructured part of the surface, in particular when no draft angle solution is possible or when it generates too much visible stray light.

[0071] In a particular embodiment, the first surface of the first lens is not structured over an internal radial height, in other words, over a radial height closer to the optical axis, over at least 30% of the first maximum radial height. The draft surfaces of the first surface comprise draft angles varying from approximately 30° at its intersection with the optical axis to a minimum draft angle of approximately 0.5° for structures on The remainder of the first surface is designed to maximize transmission and to deflect stray light from refraction, internal reflection, and external reflection from the relief surface. The second surface of the first lens has a relief angle varying substantially between 20° at its intersection with the optical axis and increasing with the radial height to substantially 50° in order to deflect internal or external reflection at the edge of the pupillary area to maximize transmission and refraction of the relief surface. The first surface of the second lens has a relief angle of substantially 25° over the 30% to 65% interior of the surface and then gradually decreasing to between 10° and 15° at maximum radial height in order to deflect external reflection at the edge of the pupillary area to maximize transmission.

[0072] All the angles of the draft surfaces are compared with respect to the optical axis. Thus, a positive draft angle means a draft angle that increases radially as it moves away from its substrate. A positive draft angle facilitates the extraction of parts manufactured by molding.

[0073] Where appropriate, when the device includes a third lens, the first surface of the third lens includes a variable relief angle in the range of 20°; 45° so as to deflect in particular external reflection and refraction by the relief surface at the limit of the pupillary area to maximize transmission.

[0074] In a particular embodiment, the lenses of the entire device comprise on their radial heights between 2 and 10 cycles of structures per millimeter.

[0075] Thus, it is understood that on one millimeter of surface of a lens of the invention, we find between 2 and 10 structures.

[0076] Preferably, the lenses comprise on their radial heights between 3 and 4 cycles of structures per millimeter.

[0077] In a preferred embodiment, the structures of the structured surfaces are Fresnel grooves.

[0078] Thus, all the structured surfaces of all the lenses that can constitute the optical device are Fresnel grooves.

[0079] In a particular embodiment, the structured surfaces can be in the form of meta-optics, or surface or volume holograms, or even diffractive structures capable of correcting chromaticism.

[0080] Without departing from the scope of the invention, the structured surfaces may be in the form of a mixture of these different forms of structures.

[0081] In a preferred embodiment, the distance between an untilted position of the so-called exit pupil area substantially centered on the optical axis, and the first maximum radial height does not exceed four times the distance separating said exit pupil area and the intersection of the first surface of the first lens with the optical axis.

[0082] Advantageously, the distance between the so-called pupil area and the maximum radial height of the first surface of the first lens of the optical device reduces the visibility of the annular rings on the structured surfaces of the different lenses. Indeed, reducing this distance reduces the eye's ability to perceive the rings due to the very short accommodation distance. In fact, a receptor with a depth of field defined by its focal length, aperture, and resolution cannot properly image an object placed too close to it; the image of the object is virtual and positioned behind the receptor, and is therefore out of focus on the receptor. Thus, bringing the object closer increases its out of focus at the receptor and therefore makes it less visible.

[0083] Alternatively or cumulatively, the frequency of the surface structures can be increased in order to decrease the apparent width of the rings which are more visible at greater radial heights.

[0084] In a particular embodiment, the second maximum radial height is less than at least twice the distance between the intersection of the optical axis and the first surface of the first lens and a non-tilted position of the so-called exit pupil area substantially centered on the optical axis.

[0085] In a preferred embodiment, the distance between the object and the first surface of the first lens is less than twice the distance between the intersection of the optical axis and the first surface and a non-tilted position of the so-called exit pupil area substantially centered on the optical axis.

[0086] In another embodiment, the distance between the object and the first surface of the first lens is less than four times the distance between the intersection of the optical axis and the first surface and a non-tilted position of the so-called exit pupil area substantially centered on the optical axis.

[0087] Alternatively, the optical device according to the invention comprises a lens including at least one branch on the peripheral portion.

[0088] Thus, the presence of at least one branch in the peripheral part of the lens makes it possible to increase the number of surfaces and thus the number of structured areas in order to have more deflection power using less lens in order to reduce the production cost while increasing the compactness of the optical device.

[0089] In a preferred embodiment, the periphery of the first surface of the optical device is such that it is at a distance less than one time the distance between the intersection of the so-called untilted exit pupil area with the optical axis and the intersection of the first surface with the optical axis. Thus, by approaching as closely as possible to the edges of the orbital cavity, the field of vision is greatly widened.

[0090] The term "perimeter of the first surface" refers to the outer edges of the first surface of the first lens of the optical device according to the invention.

[0091] The invention also relates to an image diffusion system comprising said optical device according to the invention, said diffusion system comprises a real and / or virtual image receiver, the optical axis of the optical device is substantially parallel or tilted to the optical axis of the receiver.

[0092] In a preferred embodiment, said diffusion system comprises a real and / or virtual image receiver, the optical axis of the optical device is substantially parallel to the optical axis of the receiver.

[0093] In a particular embodiment, the image diffusion system comprises a real or virtual image emitter, flat and / or curved, and is substantially perpendicular and / or tilted to the optical axis.

[0094] In a preferred embodiment, the image diffusion system includes a real and / or virtual image emitter that is substantially flat and perpendicular to the optical axis.

[0095] In a particular embodiment, the real and / or virtual image emitter is a screen that can measure from 155 millimeters to 25 millimeters and be arranged from 30 millimeters to 15 millimeters from the first surface of the first lens.

[0096] Preferably, the image diffusion system includes a receiver of the real and / or virtual deviated image, preferably, said receiver of the real and / or virtual deviated image is at least a human eye.

[0097] In another embodiment, the receiver of the deflected real and / or virtual image, said receiver is a screen.

[0098] In this same embodiment, said screen is perpendicular to the optical axis of the optical device and the object is also perpendicular to the optical axis of the optical device.

[0099] In another embodiment, the screen is tilted with respect to the optical axis of the optical device.

[0100] The optical device according to the invention takes into account positions on the optical axis of the eye but also positions around said optical center of the eye which can substantially go up to 45°, preferably 35°.

[0101] In a particular embodiment, the image diffusion system is adapted to include dioptric adjustment devices and / or interpupillary adjustment devices and / or oculometry devices and / or vergence accommodation conflict correction devices or even anti-reflective coatings on one or more of the lenses constituting the optical device.

[0102] Other advantages and features of the present invention are now described by means of purely illustrative and in no way limiting examples of the scope of the invention, and from the accompanying drawings, drawings on which the different figures represent:

[0103] [Fig-1] is a schematic representation of a perspective view of the optical device according to the invention.

[0104] [Fig.2] is a schematic representation of a perspective view of the device optics according to a particular embodiment.

[0105] [Fig.3] is a schematic representation of a perspective view of the optical device according to another embodiment.

[0106] [Fig.4] is a schematic representation of the overall slope of the first surface of the first lens of the [Fig.1].

[0107] [Fig.5] is a schematic representation of the overall slope of the first surface of the first lens of [Fig.1], according to another embodiment.

[0108] [Fig.6] is a schematic representation of a perspective view of the optical device according to the invention, for a so-called binocular exit pupil area.

[0109] [Fig.7] is a schematic representation of a perspective view of the device optics according to the invention, for a so-called pupil area decentered from the optical axis.

[0110] [Fig.8] is a schematic representation of the first surface of the first lens of [Fig.1], seen from above.

[0111] For reasons of simplicity and clarity of illustration, the elements shown in the figures have not necessarily been drawn to scale. Thus, the dimensions and relative proportions of certain elements may be exaggerated or reduced.

[0112] In the following description, identical elements, by structure or by function, appearing on different figures retain, unless otherwise specified, the same references.

[0113] It should be noted that in these figures the structural and / or functional elements common to the different variants may have the same references.

[0114] Of course, various other modifications can be made to the invention within the scope of the annexed claims.

[0115] With reference to [Fig.1] to [Fig.8], the invention relates to an optical device 1 intended to receive a real and / or virtual image of a real and / or virtual object 3 in an area called the exit pupil 4 arranged opposite to the real and / or virtual object 3.

[0116] The optical device 1 includes a first lens 5 arranged between the so-called exit pupil area 4 and the real object 3 and / or the light rays of the virtual object 3.

[0117] This first lens 5 includes an optical center 51 arranged substantially on the optical axis 2 of said optical device 1.

[0118] The first lens 5 comprises a first surface 52 formed by two portions 522, 523, a central portion 522 and a peripheral portion 523 outside the portion central 522, said peripheral portion 523 includes a first structured zone 521 extending over the entire peripheral portion 523 of the first surface 52 of the first lens 5.

[0119] The central portion 522 of the first surface 52 of the first lens 5 is crossed by the optical axis 2 and extends substantially perpendicularly with respect to said optical axis 2 of the optical device 1.

[0120] The first surface 52 of the first lens 5 comprises a continuous slope having an average absolute value substantially less than 7.5°. This absolute value applies over the entire radial height of the first surface 52, for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured parts of the first surface 52.

[0121] Said peripheral portion 523 of the first lens 5 also includes a substantially linear and inclined radial shape whose radial heights extend over the outer edges of the peripheral portion defining a first maximum radial height 524 on a first end and down to a minimum radial height 525 in the plane of section defined by the first maximum radial height 524 and the optical axis 2.

[0122] The second end of the peripheral portion 523 is defined by the minimum radial height 525 of the peripheral portion 523 of the first surface 52 of the first lens 5.

[0123] Thus, on this peripheral portion 523, the error of the average inclination of the linear approximation between the first and second end, called average radial inclination, is less than or equal to 10% of the angle formed by the normal to the optical axis and a straight line passing through a first maximum radial height and an intersection of the surface with the optical axis, called aperture angle 526 of the first surface 52 of the first lens 5.

[0124] The average radial inclination of the first surface formed by the angle between the normal to the optical axis and a straight line passing through a first maximum radial height and an intersection of the surface with the optical axis is substantially between -1° and -70° in an orthonormal frame, in which the optical axis 2 is the x-axis and the normal to the optical axis 2 is the y-axis, the center O of the orthonormal frame being the intersection of the optical axis 2 and the central portion 522 of the first surface 52.

[0125] Moreover, the average radial inclination on the radial heights is greater than at least three times an angle formed by the normal to the optical axis 2 and a straight line connecting a first maximum radial height 524 and an intersection of the first surface 52 with the optical axis 2.

[0126] The first maximum radial height 524 of the peripheral portion 523 is such that that when a light ray passes through one of these points on the whole of the peripheral portion 523, the light ray forms substantially at least an angle 527 of 75° with the optical axis 2, realizing a field of vision of at least 150°.

[0127] Moreover, on this peripheral portion 523, the average radial inclination of the shape of the first surface 52, along its structured parts is less than the average equivalent slope of the corresponding structured part.

[0128] Thus, the slope of the peripheral portion 523 is inclined and the slope of the central portion 522 is flat and perpendicular to the optical axis 2.

[0129] As illustrated in [Fig.5] the first surface 52 of the first lens 5 includes at least one inflection point 528, so that the inclination of the shape of the first surface 52 is reduced at higher radial heights.

[0130] Thus, the average radial inclination of the peripheral portion 523 of the first surface 52 of the first lens 5 on the high radial heights is greater than 1.5 times, an angle formed by the normal to the optical axis 2 and a straight line connecting a first maximum radial height 524 and an intersection of the first surface with the optical axis 2, said peripheral portion 523 is structured over its entire surface.

[0131] The inclination of the peripheral portion 523 of the first surface 52 of the first lens 5 of the optical device 1 is oriented towards the area called exit pupil 4.

[0132] The first lens 5 also includes a second surface 53 opposite the first surface 52, said second surface 53 of the first lens 5 includes a peripheral portion having a second structured area 531 extending over the entire surface of the peripheral portion of the second surface 53 of the first lens 5.

[0133] The second surface 53 of the first lens 5 also includes an average radial inclination of the shape of the second surface 53 along its structured parts, greater than the average equivalent slope of the corresponding structured part.

[0134] The optical device 1 also includes a second lens 6, through which the optical axis 2 of the optical device 1 passes, comprising a first surface 61, said first surface 61 of the second lens 6 is arranged opposite the second surface 53 of the first lens 5 at a point substantially positioned on the optical axis 2. In other words, the first 5 and the second lens 6 are brought close together at a point positioned on the optical axis 2 of the optical device 1.

[0135] The first surface 61 of the second lens 6 includes a third structured area 611, extending over the entirety of a peripheral portion of the first surface 61 of the second lens 6, said first surface 61 of the second lens 6 also includes a slope which is continuous.

[0136] The optical device 1 may also include a third lens 7 comprising a first surface 71, said first surface 71 of the third lens 7 is arranged opposite a second surface of the second lens 6, said second surface of the second lens 6 is arranged opposite to the first surface 61, at a point substantially positioned on the optical axis 2. In other words, the second 6 and the third lens 7 are brought close together at a point positioned on the optical axis 2 of the optical device 1.

[0137] The first surface 71 of the third lens 7 includes a fourth structured area 711, as well as a continuous slope.

[0138] Furthermore, the optical device 1 also includes a fourth lens 8 arranged between the first lens 5 and the so-called exit pupil area 4, said fourth lens 8 includes at least a first unstructured surface 81 and includes a discontinuous slope over at least one radial height.

[0139] The optical device 1 also includes a real and / or virtual object 3, said object 3 includes a first end, defining a second maximum radial height 31, of the object 3, said second maximum radial height 31 being inscribed in the same transverse plane as the first maximum radial height 524 and the optical axis 2.

[0140] The optical device 1 also includes a third maximum radial height 11 which may be different from the first maximum radial height 524, said first maximum radial height 524 being less than or equal to the third maximum radial height 11

[0141] Therefore, the third maximum radial height 524 is greater than the second maximum radial height 31 of the object 3, in order to obtain an object 3 of reduced size compared to the size of the first 5 and second 6 lenses of the optical device 1.

[0142] The set of structures of the structured zones 521, 531, 611, 711 of the surfaces 52, 53, 61, 71 of the different lenses 5, 6, 7 composing the optical device 1 according to the invention are Fresnel grooves.

[0143] The invention also relates to an image diffusion system comprising a real and / or virtual image emitter substantially flat and perpendicular to the optical axis 2 and a receiver of the real and / or virtual image projected, in the form of a human eye.

[0144] In any event, the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to all equivalent means and to any technically operative combination of these means.

Claims

1. Claims Optical device (1) comprising an optical axis (2), intended to project a real and / or virtual image of a real and / or virtual object (3), through a so-called exit pupil zone (4) arranged opposite to the real and / or virtual object (3), in which at least one first lens (5) is arranged between the so-called exit pupil zone (4) and the real object (3) and / or the light rays of the virtual object (3), said first lens (5) comprises an optical center (51) arranged substantially on the optical axis (2) of the optical device (1), characterized in that the first lens (5) comprises: - a first surface (52) comprising at least one first structured zone (521), preferably arranged at least in part over the entirety of a peripheral portion (523) and a continuous slope of an average absolute value substantially less than 15°, over the entire radial height of the first surface (52), for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured parts of the first surface (52), said first surface (52) comprises: • A central portion (522) crossed by the optical axis (2); • A peripheral portion (523) arranged around the perimeter of the central portion (522) comprising: • a substantially linear and inclined radial shape whose radial heights extend over the outer edges of the peripheral portion (523), defining a first maximum radial height (524) on a first end and up to a minimum radial height (525) in the section plane defined by the first maximum radial height (524) and the optical axis (2) on a second end of the peripheral portion (523), such that the error of an average inclination of the linear approximation between the first and second ends, called the average radial inclination, is substantially less than or equal to 10% of the angle formed by the normal to the optical axis and a straight line passing through a first maximum radial height and an intersection of the surface with the optical axis, called the opening angle (526) of the first surface (52), said average radial inclination comprises an angle comprised substantially between -1° and -70° relative to a normal of the optical axis (2), when the optical device (1) is inscribed in an orthonormal reference frame whose center is defined by the intersection of the optical axis and the central portion of the first surface, said average radial inclination on the first maximum radial heights (524) is greater than at least, substantially, three times the opening angle (526) of the first surface (52); • a first maximum radial height (524) such that a light ray passing through one of said first maximum radial heights (524) substantially forms a minimum angle (527) of 65° with the optical axis (2); • an average radial inclination of the surface shape along its structured parts is less than the average equivalent slope of the corresponding structured part; - a second surface (53), opposite the first surface (52) crossed by the optical axis (2) of the optical device (1), comprising: • at least one second structured zone (531), preferably arranged at least in part over the entirety of a peripheral portion of the second surface (53); • a continuous slope, the average radial inclination of the shape of the second surface (53) along its structured parts of which is greater than the average equivalent slope of the corresponding structured part, and in that the optical device (1) comprises at least one second lens (6), crossed by the optical axis (2) of the optical device (1), said second lens (6) comprises at least one first surface (61) comprising at least one third structured zone (611), preferably arranged at least in part over the entirety of a peri- spherical, said first surface (61) of the second lens (6) has a continuous slope.

2. Optical device (1) according to claim 1, characterized in that it comprises at least a fourth structured zone, (711) arranged on a first surface (71) of a third lens (7), said first surface (71) of the third lens (7) comprises a continuous slope, or arranged on a second surface opposite the first surface (61) of the second lens (6).

3. Optical device (1) according to one of the preceding claims, characterized in that it comprises a fourth lens (8) arranged between the first lens (5) and the so-called exit pupil zone (4), said fourth lens (8) comprises at least one first unstructured surface (81) and comprises a discontinuous slope over at least one radial height.

4. Optical device (1) according to one of the preceding claims, characterized in that the first surface (52) of the first lens (5) comprises a continuous slope of an average absolute value substantially less than 7.5°, over the entire radial height of the first surface (52), for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured parts of the first surface (52).

5. Optical device (1) according to one of the preceding claims, characterized in that the first surface (52) of the first lens (5) comprises on the peripheral portion (523), at least partially structured, a maximum radial height (524) so that a light ray passing through one of said maximum radial heights (524) substantially forms a minimum angle (527) of 80° with the optical axis (2) and the average radial inclination on the radial heights of the peripheral portion (523) is greater than at least twice the opening angle (526) of the first surface (52).

6. Optical device (1) according to one of the preceding claims, characterized in that it comprises a real and / or virtual object (3), said object (3) comprises a first end, defining a second maximum radial height (31) of the object (3), said second maximum radial height (31) being inscribed in the same transverse plane as the first maximum radial height (524) and the optical axis (2), said optical device (1) also comprises a third maximum radial height (11) arranged on one of the surfaces of the lenses (5, 6, 7, 8) of the optical device (1), said third maximum radial height (11) may be different from the first maximum radial height (524), said third maximum radial height (11) being greater than the second maximum radial height (525) of the object (3).

7. Optical device (1) according to one of the preceding claims, characterized in that the first surface (52) of the first lens (5) comprises at least one inflection point (528), so that the inclination of the surface shape is reduced at higher radial heights, and the average radial inclination of the peripheral portion (523) of the first surface (52) of the first lens (5) at high radial heights is greater than 1.5 times the opening angle (526) of the first surface (52) of the first lens (5), preferably the portion radially higher than the inflection point (528) is devoid of structures.

8. Optical device (1) according to one of the preceding claims, characterized in that the structures (521, 531, 611, 711) comprise relief surfaces, said relief surfaces of the set of structures (521, 531, 611, 711) of the structured surfaces of the lenses (5, 6, 7), are of such a kind that the latter deflect the so-called parasitic rays of the so-called exit pupil zone (4).

9. Optical device (1) according to one of the preceding claims, characterized in that the structures (521, 531, 611, 711) of the structured surfaces are Fresnel grooves.

10. Optical device (1) according to one of the preceding claims, characterized in that the distance between a non-tilted position of the so-called exit pupil zone (4) substantially centered on the optical axis (2) and the first maximum radial height (524) does not exceed four times the distance separating said so-called exit pupil zone (4) and the intersection of the first surface (52) of the first lens (5) with the optical axis (2).

11. Optical device (1) according to one of claims 6 to 10, characterized in that the second maximum radial height (31) is less than at least twice the distance between the intersection of the optical axis (2) and the first surface (52) of the first lens (5) and a non-tilted position of the so-called exit pupil zone substantially centered on the optical axis (2).

12. Optical device (1) according to one of claims 6 to 11, characterized in that the distance between the object (3) and the first surface (52) of the first lens (5) taken along the optical axis is less than twice the distance between the intersection of the optical axis (2) and the first surface (52) and an untilted position of the so-called exit pupil area (4) substantially centered on the optical axis (2).

13. Optical device (1) according to one of the preceding claims, characterized in that the periphery of the first surface of the optical device (1) is such as to be at a distance less than one time the distance between the intersection of the so-called exit pupil zone (4) not tilted with the optical axis (2) and the intersection of the first surface (52) with the optical axis (2).

14. Image broadcasting system comprising the optical device (1) according to one of claims 1 to 13, characterized in that it comprises a receiver of real and / or virtual images, the optical axis (2) of the optical device (1) is substantially parallel or tilted relative to the optical axis (2) of the receiver.

15. Image broadcasting system according to the preceding claim, comprising the optical device (1) according to one of claims 1 to 13, characterized in that it comprises a transmitter of real and / or virtual images which is substantially flat or curved and perpendicular to the optical axis (2).

16. Image broadcasting system comprising the optical device (1) according to one of claims 1 to 13, characterized in that it comprises a receiver of the deviated real and / or virtual image, preferably, said receiver of the deviated real and / or virtual image is at least one human eye.

Images