Compact optical device for wide fields of view

Abstract

The invention relates to an 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 what is referred to as an exit pupil area (4) arranged opposite the real and / or virtual object (3), wherein at least one first lens (5) is arranged between what is referred to as the exit pupil area (4) and the real object (3) and / or the light rays of the virtual object (3), the first lens (5) comprises an optical centre (51) arranged substantially on the optical axis (2) of the optical device (1), characterised in that the first lens (5) comprises a first surface (52) comprising a first area (521) that is at least partially structured, the first surface (52) comprises a central portion (522) and a peripheral portion (523), a second surface (53), opposite the first surface (52), comprising at least a second structured area (531) and a second lens (6) comprising a surface (61) comprising at least one structured area (611).

Description

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 optical devices making it possible to obtain a large field of vision. In the same way, the invention relates to an image diffusion system comprising said optical device.

[0002] An eyepiece lens used in wide-field optical devices is a lens or lens group 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 even automotive. Thus, ocular lenses are used in various optical systems such as image collimators, image enlargers, binocular loupes. In addition, these optical systems can be fixed such as telescopes, microscopes, head-up displays, or held like binoculars, monoculars, night vision goggles, observation glasses or even shooting glasses or even worn, or even head-up displays, near the eye, mounted on the head, extended reality displays such as virtual, mixed or augmented reality, or even 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 ultra-wide ocular lenses between 80° and 130°.

[0005] Thus, eyepiece lenses with a very large field of view are currently used particularly in the fields of astronomical observation or even for wearable displays. However, such eyepiece 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] Since then, many efforts have been made to miniaturize and lighten the weight of the extended reality displays worn, which have led to the development of more compact, lighter architectures, surfaces or ocular components for ever wider fields, such as ocular lenses slightly inclined relative to the axis of vision, by approximately 5°, eyepieces composed of one or two lenses including in their architecture one or two Fresnel surfaces and / or even a double pancake-type reflection, in order to meet the requirements of an ultra-wide field of vision.

[0008] In the same way and in order to increase the compactness and the field of these architectures, the architectures can 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 view than ultra-wide field of view ocular lenses, while being compact and lightweight, particularly in the field of worn lenses, by tilting the lenses of the optical device more strongly relative to the main axis of vision of the receiver, of 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 poor in terms of compactness, weight, field of vision or even image quality or transmission. In addition, many parasitic effects are present in the prior art solutions attempting to provide an optical device with a very large field of vision making the real or virtual image of poor quality.

[0011] Moreover, most of the architectures of these ocular lenses have a particular configuration which does not make them usable in applications other than worn displays.

[0012] In order to resolve all of these drawbacks, it is known to produce a so-called hybrid lens, comprising a curved and smooth central portion and an inclined external portion comprising Fresnel grooves on two surfaces in order to obtain a strong deflection 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 vision.

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

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

[0016] The invention relates to an optical device making it possible to obtain a very wide field of vision, beyond 130°, or even 180°, approaching 220°, all while being compact and lightweight in order to be able to produce extended reality devices of low thickness, 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 a so-called exit pupil zone arranged opposite the real and / or virtual object, in which at least a first lens is arranged between the so-called exit pupil zone and the real object and / or the light rays of the virtual object, said first lens comprises 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 comprising at least one first structured zone, preferably arranged at least partly 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 comprises a central portion crossed by the optical axis, the peripheral portion arranged on the periphery of the central portion comprising 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 up to a minimum radial height in the section 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 ends,said mean 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 mean radial inclination comprises an angle substantially between -1° and -70° relative to a normal to the optical axis, 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 mean radial inclination, in particular on the first radial heights, is greater than or equal to at least, substantially, three times the opening angle of the first surface, a first maximum radial height so 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 comprises a second surface, opposite to the first surface crossed by the optical axis of the optical device, comprising at least one 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 of which is greater than the average equivalent slope of the corresponding structured part and, the optical device comprises at least one second lens, crossed by the optical axis of the optical device, said second lens comprises at least one first surface comprising at least one third zone or the first surface of the second lens is structured,preferably arranged at least partly over the entirety of a peripheral portion, said first surface of the second lens has a continuous slope.,

[0019] Thus, such a lens having a substantially concavo-convex, meniscus, concave-plane or even concavo-concave overall shape, such that at least the slope of the peripheral portion of the first surface is inclined relative to the optical axis and having a surface comprising structures for deflecting the light rays passing through the lens allows to obtain a lens offering a so-called wide field of vision, i.e. greater than 130°, for example between 145° and 150°, or even preferably greater than 180°, for example between 190° and 220°.

[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. Alternatively, jumps may be provided at these transition zones, particularly in order to manage stray light rays, the function defining the slope as a function of the radial height remaining a continuous function.

[0021] In other words, it must therefore be understood that the slope is characterized by an average absolute value substantially less than 15°, or even less than or equal to 5°, said slope extending over the entire radial height of the first surface and in which, said continuous slope applies to both the unstructured parts and the structured parts of the first surface, and for the structured parts, the continuous slope applies to the equivalent slopes of said structured parts. Indeed, as the first surface has at least a first structured zone, the slopes of this first structured zone are therefore not perfectly continuous. Therefore, the terms "equivalent slopes" correspond to the average or effective slope of the structured zones of the first surface, or in other words only the slope facets and not the draft facets.Thus, in structured areas, the surface is not smooth but has local variations. Therefore, the equivalent slope is the overall or average slope that these structures produce, as if these structures were smoothed to obtain a continuous surface. In other words, an equivalent slope is an average of the slopes of the structures of the structured areas to form a continuous surface.

[0022] The term "radial height" is understood to mean the distance from the optical axis of a point on a lens surface measured perpendicular to the optical axis.

[0023] The term "a substantially linear and inclined radial shape" defines the fact that the peripheral portion of the first surface of the first lens is inclined to the exteriors of the first surface.

[0024] The term "maximum radial height" defines, on a given section plane, the point on the first surface of the first lens that is the furthest away measured perpendicular to the optical axis, in other words the point positioned on the outer end of the first surface.

[0025] The term "minimum radial height" means the positioned point of 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.

[0026] We speak of an average inclination on the peripheral portion approximately from -1° to -70°, by the fact that we place ourselves in an orthonormal reference frame in which the optical axis is the axis of the abscissas and the normal to the optical axis is the ordinate axis, the center of the orthonormal coordinate system being the intersection of the optical axis and the central portion of the first surface.

[0027] The term "the error of an average inclination of the linear approximation between the first and second ends, called the average radial inclination", is intended to denote the fact that a linear approximation of the inclination between the first and second ends of the peripheral portion includes an error which must be substantially less than or equal to 10% of the opening angle of the first surface. This error is also called the PV error or "peak to valley" error. Said opening angle is defined as 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. Thus, the average radial inclination includes an angle of substantially between -1° and -70° relative to a normal of the optical axis in an orthonormal reference frame.In other words, the mean radial inclination represents the overall inclination of the peripheral portion of the first surface, measured relative to the optical axis, and characterizes the general shape of this portion of the lens.

[0028] In the invention, the "radial heights" are considered to be the points that extend over the outer edges of the peripheral portion. In other words, that these points are the furthest from the center of the central portion in a three-dimensional frame of reference. Thus, all the edges of the peripheral portion, namely the points furthest from the central portion are defined by all the radial heights. More particularly, the terms "radial heights" refer to the distances measured perpendicular to the optical axis, these radial heights vary along the "outer edges" of the peripheral portion. Thus, it is understood that the inclined shape extends from the inner edge of the peripheral portion, namely, as opposed to the outer edges, the edges closer to the central portion, to the outer edges.

[0029] Thus, it is understood that a light ray passing through one of the first radial heights, and in particular through the maximum radial height, namely one of the ends of the outer edges of the peripheral portion, forms substantially a minimum angle of 65° with the optical axis.

[0030] In the same way, it will be understood according to the invention that the average radial inclination of the surface shape is less than the average equivalent slope of the structures, in particular two or three times less than the average equivalent slope of the structures. Thus, the structures on the surface create a more pronounced optical effect than what the overall shape of the surface forms. In other words, the structures increase the deflection effect of the light rays compared to what the overall shape of the surface would produce alone, which makes it possible to obtain a very wide field of vision, while maintaining an overall lens shape that remains compact.

[0031] In a preferred embodiment, the central portion of the first surface of the first lens extends substantially perpendicular to the optical axis of the optical device.

[0032] In a particular embodiment in which the first surface of the first lens, and in particular its radial shape, is devoid of an inflection point or comprises an even number of inflection points, 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.

[0033] Preferably, the radial shape, i.e. the maximum height section of the first surface in a radial section plane starting from the center of the central portion to the end of the peripheral portion, of the first surface of the first lens may be devoid of an inflection point or comprise an even number of inflection points over an area extending from the center of the central portion to the maximum height of the peripheral portion. For example, said radial shape may comprise a convex central portion and an odd number of inflection points, or alternatively a concave or flat central portion and be devoid of an inflection point or comprise an even number of inflection points.

[0034] In this same embodiment, the average radial inclination has an angle substantially between -10° and -70°, or even between -15° and -55°, or even between -20° and -50° relative to a normal of the optical axis.

[0035] In another embodiment, in which the first surface of the first lens, and in particular its radial shape, peripheral portion comprises an odd number of inflection points, the average slope of the central portion of the first surface of the first lens is less than the average slope of the peripheral portion of the first surface.

[0036] Preferably, the radial shape, i.e. the maximum height section of the first surface in a radial section plane starting from the center of the central portion to the end of the peripheral portion, of the first surface of the first lens may comprise an odd number of inflection points over an area extending from the center of the central portion to the maximum height of the peripheral portion. For example, said radial section may comprise a convex central portion and an even number of inflection points, or alternatively a concave or flat central portion and comprise an odd number of inflection points.

[0037] In this same embodiment, the average radial inclination has an angle substantially between -1° and -40°, or even between -1° and -20°, or even between -5° and -15° relative to a normal of the optical axis.

[0038] It should be noted that, whatever the embodiment considered, the number of inflection points will be counted by taking into account only inflection points having an influence on the radial shape, and by excluding in particular: inflection points whose radial height is located less than 10% of the maximum radial height in relation to the point inflection point following or relative to the maximum height if it is the last point; the inflection points located in the upper 70% of the peripheral portion.

[0039] In a preferred embodiment, the first surface of the second lens is oriented towards the second surface of the first lens.

[0040] In another embodiment, the first surface of the second lens is oriented opposite the second surface of the first lens.

[0041] In a particular embodiment, the second lens comprises a second surface opposite the first comprising an area where the second surface is structured.

[0042] 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.

[0043] In another embodiment, the pancake double reflection surfaces may be shared with other lenses.

[0044] Preferably, the first surface of the second lens and the second surface of the first lens are arranged to be brought together at a point substantially positioned on the optical axis of the optical device.

[0045] In a particular embodiment, the first and second lenses are spaced one millimeter apart on the optical axis of the optical device. It may be provided that the first and second lenses are spaced a distance less than one millimeter apart, or even that they are in contact with each other.

[0046] Advantageously, having a second lens with a structured surface on a surface arranged opposite the second surface of the first lens makes it possible to obtain a symmetry of the convergence powers between the second surface of the first lens and the first surface of the second lens, which reduces the optical aberrations, making it possible to obtain improved image quality, all while allowing an accentuated convergence of the light rays, which makes it possible to obtain an even larger field of vision without deteriorating the quality of the image, or even the compactness of the optical device.

[0047] 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 peripheral portion of each of the first lens and the first surface of the second lens.

[0048] This results in a strong deflection of the light rays from the object, which makes it possible to obtain a small object while having a compact optical device.

[0049] 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.

[0050] In a particular embodiment, all of the surfaces of all of the lenses are structured.

[0051] In a particular embodiment, the optical device comprises at least a fourth structured zone arranged on a first surface of a third lens, said first surface of the third lens comprises a continuous slope or arranged on a second surface opposite the first surface of the second lens.

[0052] In a particular embodiment, the first surface of the third lens is arranged opposite the second surface of the second lens.

[0053] Preferably, the first surface of the third lens and the second surface of the second lens are arranged to be brought together at a point substantially positioned on the optical axis of the optical device.

[0054] In a particular embodiment, the third and second lenses are spaced one millimeter apart on the optical axis of the optical device.

[0055] 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.

[0056] 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 zone, said fourth lens comprises at least one first unstructured surface and comprises a discontinuous slope over at least one radial height. Alternatively, it may be provided that the slope of the fourth lens is continuous.

[0057] 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°, across the entire radial height of the first surface, for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured portions of the first surface.

[0058] In a particular embodiment, the first surface of the first lens comprises a continuous slope of 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 portions of the first surface.

[0059] In another preferred embodiment, the first surface of the first lens comprises a substantially planar slope across the entire radial height of the first surface, for each of the slopes and equivalent slopes, respectively, of each of the unstructured and structured portions of the first surface.

[0060] In a particular embodiment, the first surface of the first lens comprises 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 substantially forms an angle of between 72.5° and 75°, or a minimum of 80°, in particular of between 95° and 110° with the optical axis and the average radial inclination on the radial heights of the peripheral portion is greater than at least twice the opening angle of the first surface, in the orthonormal reference frame defined above.

[0061] 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 the average radial inclination on the radial heights of the peripheral portion is greater than at least twice the opening angle of the first surface.

[0062] In a preferred embodiment, the first surface of the first lens comprises 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 straight line connecting a maximum radial height and an intersection of the first surface with the optical axis, in the orthonormal reference frame defined above.

[0063] Preferably, the first surface of the first lens comprises a fully structured peripheral portion.

[0064] Preferably, the optical device according to the invention 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 inscribed in the same transverse plane as the first maximum radial height and the optical axis, said optical device also comprises 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.

[0065] The third maximum radial height is arranged in the same plane as the optical surfaces of the different surfaces of the different lenses.

[0066] The term "second maximum radial height of the object" means the point most perpendicularly distant from the optical axis belonging to the object.

[0067] The term "third maximum radial height" means the point farthest, perpendicular to the optical axis, from the optical device. In other words, the maximum radial height among all surfaces in the path of the light ray having the longest deflection path.

[0068] 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, while having an optical device capable of deflecting the light rays of the object in an efficient and powerful manner.

[0069] Additionally, having a small screen size with a compact optical device allows for a more compact and lightweight extended reality system.

[0070] 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 inscribed 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.

[0071] In a preferred embodiment, the first surface of the first lens, and in particular its maximum height radial shape, comprises an odd number of inflection points, such that the inclination of the surface shape is reduced at higher radial heights, and the average radial inclination of the peripheral portion of the first surface of the first lens at high radial heights is greater than 1.5 times the opening angle of the first surface of the first lens, preferably the portion radially higher than the inflection point is devoid of structures, in the orthonormal reference frame defined above.

[0072] The term "at higher radial heights" means the distance from the optical axis, measured perpendicular to the optical axis, in other words the further away from the optical axis, thus the higher radial heights are the radial heights furthest from the optical axis of the optical device.

[0073] 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.

[0074] Preferably, the first surface of the first lens, and in particular its maximum height radial shape, comprises an odd number of inflection points, so that the inclination of the surface shape is reduced at higher radial heights, and the average radial inclination of the peripheral portion of the first surface of the first lens at high radial heights is greater than one time the opening angle of the first surface of the first lens, preferably the portion radially higher than the inflection point is devoid of structures.

[0075] More preferably, the first surface of the first lens, and in particular its maximum height radial shape, comprises an odd number of inflection points, so that the inclination of the surface shape is reduced at higher radial heights, and the average radial inclination of the peripheral portion of the first surface of the first lens at high radial heights is greater than 0.5 times, or even 0.25 times, the opening angle of the first surface of the first lens.

[0076] In another embodiment, the first surface of the first lens, and in particular its maximum height radial shape, is devoid of inflection points or comprises an even number of inflection points, and the average radial inclination of the peripheral portion of the first surface of the first lens over the radial heights is greater than four times the opening angle of the first surface of the first lens, in the orthonormal frame.

[0077] In a preferred embodiment, the structures comprise relief surfaces, said relief surfaces of the set of structures of the structured surfaces of the lenses, are such that the latter deflect the so-called parasitic rays of the so-called exit pupil zone.

[0078] The term "so-called parasitic rays" means light rays generated by the surfaces of the surface structures or which may come from the whole of the real and / or virtual object, the light rays of which coming from the points of the surface of the object are emitted in different directions and causing the presence of unwanted light such as ghost reflections, optical glare which interferes with the performance of the optical device according to the invention.

[0079] In other words, the light rays may be light rays resulting from the refraction of the blank of the object, from the partial or total reflection of the blank of the object on the internal surface of the surface of the blank, the partial or total reflection of the blank on the external surface of the blank, the light rays having a refraction slope after and before the refraction of the blank of the object.

[0080] Advantageously, these relief surfaces themselves deflect the stray light generated by the structured surface areas outside the so-called exit pupil zone.

[0081] 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 it generates too many visible stray light rays.

[0082] In a particular embodiment, the first surface of the first lens is not structured on an inner radial height, in other words on a radial height closer to the optical axis, on at least 30% of the first maximum radial height, said clearance surfaces of the first surface comprise clearance angles varying between substantially 30° at its intersection with the optical axis to a minimum clearance angle of substantially 0.5° for the structures on the remainder of the first surface so as to maximize transmission and to deflect in particular the stray light of refraction, internal reflection and external reflection of the clearance surface, the second surface of the first lens comprises a clearance angle varying substantially between 20° at its intersection with the optical axis and increasing with the radial height to substantially 50° so as to deflect in particular the internal or external reflection at the limit of the pupillary zone to maximize transmission and refraction of the clearance surface, the first surface of the second lens has a clearance angle substantially of the order of 25° on the 30% to 65% inside the surface then which gradually descends to between 10° and 15° at maximum radial height so as to deflect in particular the external reflection at the limit of the pupillary zone to maximize transmission.

[0083] All draft surface angles are compared with respect to the optical axis. Thus, a positive draft angle means a draft inclination that increases radially as it moves away from its substrate. A positive draft angle facilitates the extraction of parts manufactured by casting.

[0084] Where appropriate, when the device comprises a third lens, the first surface of the third lens comprises a variable clearance angle in the range 20°; 45° so as to deflect in particular external reflection and refraction by the clearance surface at the edge of the pupillary zone to maximize transmission.

[0085] In a particular embodiment, the lenses of the entire device comprise on their radial heights between 2 and 10 cycles of structures per millimeter.

[0086] Thus, we understand that on a millimeter of surface of a lens of the invention, we find between 2 and 10 structures.

[0087] Preferably, the lenses comprise on their radial heights between 3 and 4 cycles of structures per millimeter.

[0088] In a preferred embodiment, the structures of the structured surfaces are Fresnel grooves.

[0089] Thus, all the structured surfaces of all the lenses that can constitute the optical device are Fresnel grooves.

[0090] In a particular embodiment, the structured surfaces may be in the form of meta-optics, or surface or volume holograms, or even diffractive structures capable of correcting chromatism.

[0091] 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.

[0092] In a preferred embodiment, the distance between a non-tilted 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 so-called exit pupil area and the intersection of the first surface of the first lens with the optical axis.

[0093] Advantageously, the distance between the so-called pupil zone and the maximum radial height of the first surface of the first lens of the optical device makes it possible to reduce the visibility of the annular rings of the structured surfaces of the different lenses. Indeed, reducing the distance makes it possible to reduce the eye's ability to perceive the rings due to the very short accommodation distance. Indeed, a receiver having a depth of field defined in particular by its focal length, its aperture and also its resolution, cannot correctly image an object placed too close to it, the image of the object is virtual and is positioned behind the receiver and is therefore defocused on the receiver. Thus, bringing the object closer makes it possible to increase its defocus at the receiver and therefore to make it less visible.

[0094] Alternatively or cumulatively, the frequency of surface structures can be increased to decrease the apparent width of the rings which are more visible at greater radial heights.

[0095] 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 zone substantially centered on the optical axis.

[0096] 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 an untilted position of the so-called exit pupil area substantially centered on the optical axis.

[0097] 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 an untilted position of the so-called exit pupil area substantially centered on the optical axis.

[0098] Alternatively, the optical device according to the invention comprises a lens comprising at least one branch on the peripheral portion.

[0099] 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 zones 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.

[0100] 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 close as possible to the edges of the orbital cavity, the field of vision is greatly widened.

[0101] The term "periphery of the first surface" means the outer edges of the first surface of the first lens of the optical device according to the invention.

[0102] The invention also relates to an image broadcasting system comprising said optical device according to the invention, said broadcasting 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.

[0103] In a preferred embodiment, said broadcasting 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.

[0104] In a particular embodiment, the image broadcasting system comprises a real or virtual image transmitter, flat and / or curved and is substantially perpendicular and / or tilted to the optical axis.

[0105] In a preferred embodiment, the image broadcasting system comprises a real and / or virtual image transmitter that is substantially flat and perpendicular to the optical axis.

[0106] In a particular embodiment, the transmitter of real and / or virtual images is a screen which may measure from 155 millimeters to 25 millimeters and be arranged from 30 millimeters to 15 millimeters from the first surface of the first lens.

[0107] Preferably, the image broadcasting system 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.

[0108] In another embodiment, the receiver of the deviated real and / or virtual image, said receiver is a screen.

[0109] 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.

[0110] In another embodiment, the screen is tilted relative to the optical axis of the optical device.

[0111] 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 be substantially up to 45°, preferably 35°.

[0112] In a particular embodiment, the image broadcasting system is adapted to comprise dioptric adjustment devices and / or interpupillary adjustment devices and / or eye tracking devices and / or vergence accommodation conflict correction devices or even anti-reflective coatings on one or more of the lenses constituting the optical device.

[0113] Other advantages and characteristics of the present invention are now described with the aid of examples which are purely illustrative and in no way limitative of the scope of the invention, and from the appended drawings, drawings in which the various figures represent:

[0114] [Fig. 1] is a schematic representation of a perspective view of the optical device according to the invention.

[0115] [Fig. 2] is a schematic representation of a perspective view of the optical device according to a particular embodiment.

[0116] [Fig. 3] is a schematic representation of a perspective view of the optical device according to another embodiment.

[0117] [Fig. 4] is a schematic representation of the overall slope of the first surface of the first lens of [Fig. 1],

[0118] [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.

[0119] [Fig. 6] is a schematic representation of a perspective view of the optical device according to the invention, for a zone called the binocular exit pupil.

[0120] [Fig. 7] is a schematic representation of a perspective view of the optical device according to the invention, for a so-called pupil zone off-centered from the optical axis.

[0121] [Fig. 8] is a schematic representation of the first surface of the first lens of [Fig. 1], viewed from above.

[0122] For reasons of simplicity and clarity of illustration, the elements represented in the Figures may not necessarily have been drawn to scale. Therefore, the relative dimensions and proportions of certain elements may be exaggerated or even reduced.

[0123] In the following description, elements which are identical, by structure or by function, appearing in different figures retain, unless otherwise specified, the same references.

[0124] It should be noted that in these figures the structural and / or functional elements common to the different variants may have the same references.

[0125] Of course, various other modifications may be made to the invention within the scope of the appended claims.

[0126] 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 a so-called exit pupil zone 4 arranged opposite the real and / or virtual object 3.

[0127] The optical device 1 comprises a first lens 5 arranged between the so-called exit pupil zone 4 and the real object 3 and / or the light rays of the virtual object 3.

[0128] This first lens 5 comprises an optical center 51 arranged substantially on the optical axis 2 of said optical device 1.

[0129] The first lens 5 comprises a first surface 52 formed by two portions 522, 523, one called central 522 and one called peripheral 523 outside the central portion 522, said peripheral portion 523 comprises a first structured zone 521 extending over the entire peripheral portion 523 of the first surface 52 of the first lens 5.

[0130] 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 relative to said optical axis 2 of the optical device 1.

[0131] 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.

[0132] Said peripheral portion 523 of the first lens 5 also comprises a substantially linear and inclined radial shape whose radial heights extend on the outer edges of the peripheral portion 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.

[0133] 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.

[0134] Thus, on this peripheral portion 523, the error of the average inclination of the linear approximation between the first and second ends, 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 axis optical, said opening angle 526 of the first surface 52 of the first lens 5.

[0135] 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 reference frame, in which the optical axis 2 is the abscissa axis and the normal to the optical axis 2 is the ordinate axis, the center O of the orthonormal reference frame being the intersection of the optical axis 2 and the central portion 522 of the first surface 52.

[0136] In addition, the average radial inclination over 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.

[0137] The first maximum radial height 524 of the peripheral portion 523 is such that when a light ray passes through one of these points over the entire peripheral portion 523, the light ray forms substantially at least an angle 527 of 75° with the optical axis 2, achieving a field of vision of at least 150°.

[0138] Furthermore, 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.

[0139] 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.

[0140] As illustrated in [Fig. 5] the first surface 52 of the first lens 5 includes at least one inflection point 528, such that the inclination of the shape of the first surface 52 is reduced at higher radial heights.

[0141] 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.

[0142] 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 so-called exit pupil zone 4.

[0143] The first lens 5 also comprises a second surface 53 opposite the first surface 52, said second surface 53 of the first lens 5 comprises a peripheral portion having a second structured zone 531 extending over the entire surface of the peripheral portion of the second surface 53 of the first lens 5.

[0144] The second surface 53 of the first lens 5 also comprises an average radial inclination of the shape of the second surface 53 along its structured portions, greater than the average equivalent slope of the corresponding structured portion.

[0145] The optical device 1 also comprises a second lens 6, crossed by the optical axis 2 of the optical device 1 comprising a first surface 61, said first surface 61 of the second lens 6 is arranged against 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 closer to each other at a point positioned on the optical axis 2 of the optical device 1.

[0146] The first surface 61 of the second lens 6 comprises a third structured zone 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 comprises a slope which is continuous.

[0147] The optical device 1 may also comprise a third lens 7 comprising a first surface 71, said first surface 71 of the third lens 7 is arranged against a second surface of the second lens 6, said second surface of the second lens 6 is arranged opposite 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 closer to each other at a point positioned on the optical axis 2 of the optical device 1.

[0148] The first surface 71 of the third lens 7 comprises a fourth structured zone 711, as well as a continuous slope.

[0149] In addition, the optical device 1 also 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.

[0150] The optical device 1 also 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.

[0151] The optical device 1 also comprises a third maximum radial height 11 which may be different from the first maximum radial height 524, said first maximum radial height 524 is less than or equal to the third maximum radial height 11

[0152] 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.

[0153] All of the structures of the structured areas 521, 531, 611, 711 of the surfaces 52, 53, 61, 71 of the different lenses 5, 6, 7 making up the optical device 1 according to the invention are Fresnel grooves.

[0154] The invention also relates to an image broadcasting system comprising a real and / or virtual image transmitter which is substantially flat and perpendicular to the optical axis 2 and a receiver of the projected real and / or virtual image, in the form of a human eye.

[0155] 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 effective combination of these means.

Claims

Claims

1. 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.a first surface (52) comprising at least one first structured area (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: i. A central portion (522) crossed by the optical axis (2); ii. The peripheral portion (523) arranged on the periphery 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 (524) is greater than or equal to 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; b. a second surface (53), opposite the first surface (52) crossed by the optical axis (2) of the optical device (1), comprising: i. 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); ii. a continuous slope, the average radial inclination of the shape of the second surface (53) along its structured parts being 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 peripheral portion, 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

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 an angle (527) of between 72.5° and 75° or a minimum 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 an odd number of inflection points (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 a non-tilted position of the so-called exit pupil zone (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