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    • 专利摘要:
    The invention relates to a system for forming (1) a floating image, comprising: - at least one image projector (10), - a display screen (20) comprising transparent portions (21) and diffusing portions (22), and - a semi-reflecting structure (30) disposed between the image projector (10) and the display screen (20), having a so-called transmission face (30t) adapted to transmit light beams from the image projector (10) and light beams from a scene to be observed, and an opposite so-called reflection face (30r) adapted to reflect light beams from the display screen (20) , so as to form a so-called floating virtual image of the image projected on the display screen (20).
    公开号:FR3057731A1
    申请号:FR1659887
    申请日:2016-10-13
    公开日:2018-04-20
    发明作者:Christophe Martinez
    申请人:Commissariat a lEnergie Atomique CEA；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    Holder (s): COMMISSIONER FOR ATOMIC ENERGY AND ALTERNATIVE ENERGIES Public establishment.
    Extension request (s)
    Agent (s): INNOVATION COMPETENCE GROUP.
    Q4) SYSTEM FOR FORMING A FLOATING IMAGE.
    FR 3 057 731 - A1 _ The invention relates to a system for forming (1) a floating image, comprising:
    - at least one image projector (10),
    a display screen (20) comprising transparent portions (21) and diffusing portions (22), and
    - a semi-reflecting structure (30) disposed between the image projector (10) and the display screen (20), comprising a so-called transmission face (30t) adapted to transmit light beams coming from the projector image (10) and light beams coming from a scene to be observed, and an opposite face called reflection (30r) adapted to reflect light beams coming from the display screen (20), so as to form an image virtual, called floating, of the image projected on the display screen (20).
    FLOATING IMAGE FORMATION SYSTEM
    TECHNICAL FIELD [001] The field of the invention is that of systems for forming a so-called floating image, that is to say of an image appearing in superposition of a scene.
    PRIOR ART [002] Floating image formation systems have existed in the entertainment field since the 19th century and are currently being developed to address in particular the field of advertising and event communication. They are based on an optical illusion effect, known as the Pepper ghost, the principle of which is recalled with reference to FIG. 1A which illustrates a floating image forming system described in document US2009 / 0009862.
    In this example, the system A1 comprises an image source A2, for example an emissive screen, adapted here to provide a plurality of source images at its emission face A3, and a semi-reflecting structure A4 in the shape of a pyramid with a polygonal base positioned inversely with respect to the image source A2, that is to say that its apex A is situated opposite the emissive face A3 of the source of picture A2. Thus, the semi-reflecting faces A5 of the pyramid A4 are oriented towards the image source A2 and towards the environment of the system Al.
    The image source A2 provides a plurality of source images each positioned opposite a semi-reflecting face A5 of the pyramid A4. Thus, the light beams of each image supplied are partly reflected by the corresponding side A5 of the pyramid A4 in the direction of the environment. An observer placed in front of one of the faces A5 of the pyramid A4 then sees a virtual image of the image provided by the image source A2, this virtual image being positioned in a virtual plane located inside the pyramid A4 . The semi-transparency of the pyramidal structure A4 makes it possible to form an image overlaying the scene, which gives the observer the impression of observing a floating image. Furthermore, in this example, an observer who turns around the Al system would see different virtual images located inside the pyramid A4, which would give the impression of observing a floating three-dimensional image.
    A drawback of this type of system A1 is that the semi-reflecting structure A4 is necessarily oriented so that the semi-reflecting faces A5 are oriented towards the image source A2 and towards the environment of the system A1. as a result, the field of vision is limited by the emission face A3 of the image source A2 on the one hand and by the base of the semi-reflecting structure A4 on the other hand. In addition, the inverted orientation of the pyramid A4 with respect to the image source A2 requires the provision of retaining elements for the pyramid A4, which adds an unsightly effect to the system and reduces the viewing comfort of the observer.
    Document US3551043 describes an Al system for projecting images onto a translucent A6 display screen. As illustrated in FIG. 1B, the system A1 comprises a first projector A7a and a second projector A7b, adapted to each project a source image on the same display screen. Projectors A7a, A7b include an image source and an optical projection system. A semi-reflecting structure A4 is positioned on the optical path going from the first projector A7a to the display screen A6, and on the optical path going from the second projector A7b to the display screen A6. It makes it possible to reflect the light beams coming from the first projector A7a in the direction of the screen A6, and to transmit the light beams coming from the second projector A7b in the direction of the screen A6. Thus, in operation, the image forming system A1 displays the image supplied by the first projector A7a on the screen A6, superimposed on the image supplied by the second projector A7b. An observer positioned on the opposite side of the A6 display screen is then able to view the two images displayed, one being superimposed on the other.
    A drawback of this system A1 is in particular that the display screen A6 is translucent and not transparent, this to avoid that the observer cannot clearly see the second projector A7b located behind the screen A6. Thus, this Al system does not ensure the formation of a floating image, that is to say of an observable image superimposed on a scene located behind the display screen.
    PRESENTATION OF THE INVENTION The aim of the invention is to remedy at least in part the drawbacks of the prior art, and more particularly to propose a floating image formation system, which provides comfort of vision to the eye. observer of the floating image, while improving the visual experience of observing a floating image superimposed on the scene. For this, the object of the invention is a system for forming a floating image, comprising at least one image projector, adapted to project a source image, and a display screen adapted to display the projected image. by the image projector.
    According to the invention, said display screen comprises transparent portions and diffusing portions, being adapted, moreover, to partially transmit incident light beams. And the floating image forming system further comprises a semi-reflecting structure disposed between the image projector and the display screen, comprising a so-called transmission face adapted to transmit light beams coming from the image projector. and light beams coming from a scene to be observed, and an opposite face known as of reflection adapted to reflect light beams coming from the display screen, so as to form a virtual image, known as floating, of the projected image on the display screen, said floating image being observable through the display screen by means of the semi-reflecting structure.
    Some preferred but non-limiting aspects of this floating image forming system are as follows.
    The diffusing portions of said display screen can also be reflective so that the light beams coming from the semi-reflecting structure and scattered by the diffusing portions are reflected towards the semi-reflecting structure.
    The diffusing portions of said display screen may also be retroreflective so that the light beams coming from the semireflective structure with an axis of incidence with respect to the diffusing portions are reflected by the diffusing portions in the direction of the semi-reflecting structure with an axis of reflection identical to the axis of incidence.
    The display screen may comprise a plurality of substantially flat and distinct display faces two by two, and the semi-reflecting structure may also include a plurality of substantially planar and inclined faces two by two, each being optically associated with a display face.
    Said display faces and said faces of the semi-reflective structure can extend continuously around a so-called reference axis passing through a return structure of said projector, the display screen and the semi-structure reflective each forming a pyramid cone.
    The projector can be adapted to provide a plurality of source images, and can comprise at least one optical projection system adapted to optically conjugate a source image to a different face of the display screen.
    The projector may include a return structure having a plurality of reflective faces, each of said reflecting return faces being optically associated with a source image and with a display face.
    The projector may include a deflection structure having a reflective face movable in rotation about a reference axis so as to project a source image on said faces of the display screen.
    The diffusing portions of said display faces can be:
    retro-reflecting so that the light beams coming from the semi-reflecting structure with an axis of incidence with respect to the diffusing portions are reflected by the diffusing portions in the direction of the semi-reflecting structure with an axis of reflection identical to l axis of incidence, and adapted to diffuse the retro-reflected light beams in a diffusion cone, each diffusion cone associated with a display face being partially covering the diffusion cone associated with an adjacent display face.
    The display screen and the semi-reflecting structure may each have a single substantially curved face.
    Said curved faces of the display screen and of the semi-reflecting structure may extend continuously around a reference axis passing through a return structure of said projector, the display screen and the structure semi-reflecting each forming a cone of revolution with respect to said reference axis.
    The image provided by the image source can be an anamorphic image.
    The transparent portions of the display screen can be adapted to transmit light beams from the semi-reflecting structure, and the diffusing portions can be adapted to diffuse light beams from the semi-reflecting structure towards of said semi-reflecting structure.
    Each diffusing portion may be surrounded by a transparent portion, and the display screen may have a rate of occultation by the diffusing portions less than or equal to 20%.
    BRIEF DESCRIPTION OF THE DRAWINGS Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of nonlimiting example, and made with reference to the accompanying drawings in which:
    Figures IA and IB, already described, illustrate two examples of an image-forming system, floating (fig.lA) and non-floating (fig.lB), according to the prior art;
    Figure 2 illustrates, partially and schematically, an image forming system according to one embodiment;
    FIGS. 3A to 3D are sectional views, partial and schematic, of different examples of a display screen with transparent portions and diffusing portions;
    FIGS. 4A to 4D are sectional views, partial and schematic, of different examples of a display screen with transparent portions and diffusing and reflecting portions;
    FIGS. 5A to 5C are sectional views, partial and schematic, of different examples of a display screen with transparent portions and diffusing and retroreflective portions;
    FIGS. 6A and 6B illustrate, partially and schematically, in section (FIG. 6A) and in perspective (6B), an image forming system according to another embodiment, in which the projector includes a deflection mirror ;
    Figures 7A, 7B and 7C illustrate, partially and schematically, different examples of an image forming system according to another embodiment, making it possible to form a quasi-three-dimensional floating image;
    Figures 8A and 8B illustrate, partially and schematically, an image forming system according to another embodiment, the display screen and the semi-reflecting structure of which are curved and coaxial; and FIG. 8C illustrates, partially and schematically, an image forming system according to a variant in which the projector is a scanning projection device.
    DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS In the figures and in the following description, the same references represent the same or similar elements. In addition, the different elements are not shown to scale so as to favor the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with one another. Unless otherwise indicated, the terms "substantially", "approximately", "in the order of" mean to the nearest 10%.
    In general, the floating image forming system includes a projector of at least one source image, adapted to ensure the projection of the source image on a display screen. It also includes a display screen adapted to ensure the display of the projected image and to allow observation of the scene behind the screen. Also, it has transparent portions and diffusing portions distributed over all or part of its surface. Preferably, as detailed below, the diffusing portions are also reflective, even retro-reflective. The system also includes a semi-reflective floating image formation structure, located between the projector and the display screen, and adapted to form a virtual, so-called floating, image of the image displayed by the screen.
    FIG. 2 schematically illustrates a system 1 for forming a floating image according to a first embodiment, in which the projector 10 comprises a semi-reflecting plate 13 for deflection.
    The image projector 10 comprises at least one image source 11 and an associated projection optical system 12, and preferably a return structure 13. The image source 11, for example an emissive screen , is adapted to provide at least one image to be displayed, called the source image. It can be, among others, a liquid crystal screen (LCD screen), a screen with light emitting diodes (LED), possibly organic (OLED), even a cathode screen. The image source 11 will advantageously consist of a matrix of micro mirrors of the DMD (for Digital Micromirror Device) type associated with an RGB light source.
    The optical projection system 12 is adapted to project the image provided by the image source 11 on the display screen 20, that is to say to project on the screen 20 a real image from the image provided. In other words, the optical projection system 12 ensures the optical conjugation of the emission face of the image source 11 and the display screen 20. It can thus include, for example, one or more lenses, and is arranged between the image source 11 and the display screen 20, and in this example between the image source 11 and the return structure 13.
    The projector 10 in this example comprises a deflection structure 13 adapted to reflect at least partially, or even completely, the light beams coming from the image source 11 in the direction of the display screen 20. The structure of reference 13 is formed here of a semi-reflecting plate, arranged on the optical path going from the projector 10 to the display screen 20, and here between the display screen 20 and the scene to be observed. The deflection blade 13 has a so-called internal semi-reflecting face 13i facing the projector 10 and the display screen 20, and a so-called external face 13e, opposite the internal face 13i. It can be oriented, as illustrated, so as to form an angle of inclination, for example 45 °, with the display screen 20. The deflection blade 13 can be replaced by an interference filter performing the same optical function as the semi-reflective strip, or even, as will be detailed later, by a mirror. In this example, the return structure 13 has, in association with the display screen 20, a pyramid shape the base of which is located opposite the projector 10.
    The screen is a partially transparent display screen 20, and for this includes transparent portions 21 and diffusing portions 22 distributed over all or part of its surface (cf. FIG. 3A and following). It has a so-called internal face 20i intended to receive the light beams coming from the projector 10, and an opposite so-called external face 20e, opposite which an observer is positioned. The display screen 20 is thus adapted to diffuse more or less strongly, at the diffusing portions 22, part of the beams incident on its internal face 20i, in particular the beams coming from the projector 10. It is also adapted to transmit , at the transparent portions 21, another part of the beams incident on its internal face 20i, in particular the beams coming from the scene. To form a real image of the image supplied by the projector 10, the display screen 20 is arranged in the image plane of the projection optical system 12.
    The transparent portions 21 and the diffusing portions 22 are distinct from each other, and are preferably arranged mutually so that a diffusing portion 22 is surrounded, in the plane of the screen, by a transparent portion 21. By transparent, we mean the optical property of an element, material, surface ... which lets light through and through which we can clearly distinguish the scene behind the element in question. A transparent portion 21 is then distinguished from a translucent portion which lets the light through but by diffusing it in such a way that the scene cannot be clearly distinguished through it. A transparent portion 21 here has smooth surfaces, that is to say having a so-called "optical polish" quality allowing the transmission of light beams without significant modification of their propagation characteristics. A smooth surface preferably has a surface roughness of less than 20 nm RMS (for Root Mean Square) corresponding to the square root of the average of the amplitude of the roughness of the surface, and preferably between 2 nm and 15 nm RMS . The display screen 20, thanks to its transparent portions 21, is then distinguished from translucent screens, such as that of the document US3551043 cited above which transmits the light coming from the scene but by diffusing it in such a way that the objects of the scene are not distinguishable or clearly visible.
    The semi-reflecting structure 30 is adapted on the one hand to transmit the beams propagating in the direction of the display screen 20, in particular the beams coming from the projector 10 and the beams coming from the scene, and d on the other hand to reflect the beams coming from the display screen 20.
    It has a first face called transmission 30t, facing the stage and here oriented towards the return structure 13, and a second face called reflection 30r, opposite the first face 30t, oriented towards the screen. display 20. Thus, the incident beams on its transmission face 30t are transmitted partially and preferably completely, and the incident beams on its reflection face 30r are partially and preferably completely reflected.
    The semi-reflecting structure 30 is arranged on the optical path from the projector 10 to the display screen 20, and between the scene to be observed and the display screen 20. It is here substantially parallel to the display screen 20 but may have a non-zero angle of inclination with the latter. It is formed here from a single semi-reflecting plate, but can be replaced by an interference filter performing the same optical function as the semi-reflecting plate.
    In operation, the image source 11 of the projector 10 provides a so-called source image, which is projected by the optical system 12 on the display screen 20. More specifically, the light beams emitted by the source of image 11 are projected by the optical system 12, and reflected by the return structure 13 then transmitted by the semi-reflecting structure 30 towards the display screen 20. The screen being placed in the image plane of the optical system 12 of projection, a real image of the source image is then formed on the display screen 20 by its diffusing portions 22. The semi-reflecting structure 30 then forms a virtual image of the real image displayed. More precisely, the beams coming from the real image displayed are reflected by the semi-reflecting structure 30 in the direction of the display screen 20, and transmitted by the latter by its transparent portions 21. In addition, the light beams emitted by the scene are transmitted by the return structure 13, the semi-reflecting structure 30 and then the display screen 20, in the direction of an observer placed facing the external face 20e of the display screen 20.
    Thus, such an observer is able to see a virtual image, formed by the semi-reflecting structure 30, of the real image projected on the display screen 20. Thus, the virtual image, n 'need not be materialized on a surface of a display screen 20 to be observable as in the document US3551043 cited above, seems to really float on top of the scene. Furthermore, unlike floating image forming systems like that of document US2009 / 0009862 cited above, the training system 1 according to the invention does not require the use of a semi-reflective pyramid structure with reverse orientation. , which provides observers with improved viewing comfort. Indeed, the field of vision of the observer is not limited or hindered by the base of the inverted pyramid structure, nor by the mechanical holding elements of the inverted pyramid.
    Figures 3A to 3D illustrate examples of display screen 20 according to one embodiment, in which the screen comprises a plate 23, or a film or a sheet, in at least one transparent material, for example made of glass or plastic, at which level there are diffusing portions 22 and transparent portions 21.
    3A illustrates a display screen 20 formed of a plate 23 of the same transparent material, including a first face, partially coated with diffusing portions 22, forming the internal face 20i of the screen. These are formed by a layer 24, one face of which has micro- or nanostructures 25 adapted to scatter the incident light. The structures 25 can in particular be obtained by lithography or by molding.
    Alternatively, as illustrated in Figure 3B, the structures 25 can be made directly at the inner face 20i of the transparent plate 23, and not on a deposited layer 24. Structures 25 can, alternatively or in addition, be formed at the opposite face of the plate 23 which forms the external face 20e of the display screen 20.
    Alternatively, as shown in Figure 3C, the display screen 20 may be similar to that of fig.3A and is distinguished in that the diffusing portions 22 are formed by deposition, for example by screen printing, a layer 24 made of a transparent material charged with diffusing particles 26.
    Alternatively, as illustrated in Figure 3D, the display screen 20 may be formed of a plate 23 made in one piece having areas of a first transparent material, thus forming the transparent portions 21 , and zones including a second material formed of a transparent binder charged with diffusing particles 26, thus forming the diffusing portions 22. The zones with diffusing particles 26 can extend over all or part of the thickness of the plate 23.
    In general, the display screen 20 also includes transparent portions 21, formed here of areas of the transparent plate 23 whose external and internal faces are optically smooth, that is to say that the surface roughness is less than or equal to 20nm RMS. The transparent portions 21 are preferably arranged so as to surround the diffusing portions 22 partially or even completely, in the plane of the screen.
    Figures 4A to 4D illustrate examples of a display screen 20 according to another embodiment, in which the diffusing portions 22 are also opaque, and preferably reflective, so as to limit the transmission of the beams light coming from the semi-reflecting structure and diffused by your diffusing portions 22.
    For cefa, your diffusing portions 22 further include a layer 27 of an opaque material, and preferably reflective, for example a metallic material such as aluminum or silver. The layer 27, here reflective, can thus be a thin layer with a thickness of a few nanometers to a few microns, for example between 10 nm and 10 pm, preferably between 30 nm and 100 nm.
    The thin reflective layers 27 are located at the diffusing portions 22 and not at the transparent portions 21. Each reflective layer 27 may be located in contact with the internal face 20i of the transparent plate 23, so as to be covered by structured layer 24 (fig. 4A). It may alternatively be located in contact with the external face 20e, opposite the structured layer 24 (not shown); opposite the structured area 22 of the internal face 20i of the transparent plate 23 (fig.4B); or opposite the layer 24 with diffusing particles 26 (FIG. 4C). It can also be in contact with the external face 20e of the plate 23, at the level of a diffusing zone 22 formed from the second material comprising diffusing particles 26 (FIG. 4D).
    In general, a display screen 20, the diffusing portions 22 of which are also reflective, makes it possible to limit the transmission of the light beams of the real image projected towards the observer, and therefore to increase the light flux. in the direction of the semi-reflecting structure 30. Thus, the optical efficiency of the floating image forming system 1 is increased, insofar as the floating image becomes brighter. In addition, the diffusion of the real image projected towards the observer is limited. The observation of the floating image through the display screen 20 is thus less 'p aras itated' by the actual projected image, which improves the comfort and the quality of vision of the floating image through of this same screen.
    Figures 5A to 5C illustrate examples of a display screen 20 according to another embodiment, in which the diffusing portions 22 are also retroreflective. The display screen 20 is similar to that of the examples in FIGS. 3A-3D and 4A-4D and differs essentially therefrom in that the diffusing portions 22 comprise at least one structuring 28 in a cube corner so as to provide retro reflection of the incident beams on the internal face in the direction of the semi-reflecting structure 30.
    FIG. 5A illustrates an example in which each diffusing portion 22 comprises, at the level of the external face 20e of the display screen 20, a structure 28 in a cube corner. This structure 28 projects from a plane of the external face 20e of the display screen 20, and forms a protuberance. Each structure 28 is a cube corner-shaped protuberance, the bases of the protrusions here being substantially parallel to the external face 20e of the display screen 20. In this example, each diffusing portion 22 comprises a diffusing layer 24, here structured, located on the internal face 20i of the display screen 20 and positioned opposite the protuberance 28 at the corner of a cube, that is to say at the right of the cube corner 28 according to the thickness of the plate 23 transparent. To ensure the partial transparency property of the display screen 20, the cube corners 28 are not adjacent, but are separated from each other by the transparent portions 21, formed by substantially flat and smooth areas.
    5B illustrates an example of a display screen 20 similar to that of fig.5A, which is essentially distinguished in that the diffusion function of the diffusing portions 22 is provided, not by a layer diffusing deposited, but by the surface imperfections of the external face 20e at the level of the cube corner protrusions 28. These surface imperfections can be obtained, for example, by mechanical surface structuring, lithography or molding.
    Furthermore, a metal layer (not shown) can also be provided at the external face of the screen, in the diffusing and retroreflective portions 22, to promote the reflection of the incident light. Other transparent reflective diffusing films can be used, for example holographic films, an example of which is given in document US Pat.
    FIG. 5C illustrates another example in which each diffusing portion 22 comprises a structuring 28 in a cube corner in the form of a notch in a transparent plate 23. The surface of the cube corner notch 28 is advantageously coated with a thin reflective layer 27, for example metallic, such as a layer of aluminum or silver with a thickness advantageously between 20 nm and 100 nm. The notches are made in a first plate 23, to which a second transparent plate 29 is fixed, by means of a layer of transparent glue. Structures 25 may also be provided opposite the cube corners 28, on the face 20i of the screen 20, to reinforce the scattering of the light beams.
    The light beam diffusion function can be provided by the presence of the structures 25, as described above, or, as a variant, can be provided by the surface imperfections formed by the edges of the cube corners 28.
    As an alternative to the examples of display screens with diffusing and retroreflective portions described above, the retro-reflection function can be provided, not by cube corner structures, but by a layer of a material to be microbead base. As described in document WO2015 / 158999, one face of the screen can thus include areas coated with the layer based on microbeads, thus forming the retro-reflecting diffusing portions 22, and areas not coated with this layer, thus forming the transparent portions 21.
    Generally, the rate of concealment by the diffusing portions 22, that is to say the ratio between the cumulative surface of the diffusing portions 22 on the total surface of the internal or external face of the screen d display 20 is advantageously less than or equal to 50% and preferably less than or equal to 20%, so as to allow good viewing of the scene in transparency through the display screen 20. Other values are possible depending on the applications.
    Such a display screen 20 in which the diffusing portions 22 are also retro-reflecting makes it possible to further increase the optical efficiency of the system 1 of floating image formation. The floating image, observed through the display screen 20 and the semi-reflecting structure 30, then appears brighter.
    Figures 6A and 6B are schematic views, in section (fig.6A) and in perspective (fig.6B), illustrating a system 1 for forming a floating image according to another embodiment, making it possible to obtain a high light output.
    Here, the projector 10 return structure is a mirror which provides substantially total reflection of the light beams emitted by the image source 11 and transmitted by the optical system 12 of projection. Also, the light output of the floating image forming system 1 is then increased.
    We denote here Ap the optical projection axis, corresponding to the axis of propagation of the beams emitted by the projector 10 and transmitted by the semi-reflecting structure 30 then by the display screen 20. We also note Ao the optical observation axis, corresponding to the optical axis of the retro-reflected beams along the projection axis Ap, then reflected by the semi-reflecting structure 30 and finally transmitted by the display screen 20. On defines the angle ΔΘ as the difference between the propagation axis Ap and the observation axis Ao.
    The various elements of the floating image forming system 1 are preferably arranged, that is to say positioned and oriented mutually, so that the projection axis Ap is distinct from the observation axis Ao. Thus, an observer is able to observe the floating image superimposed on the scene, without being bothered by the light beams coming from the projector 10 and directly transmitted through the transparent portions 21 of the display screen 20. From preferably, the angular difference ΔΘ between the projection axis Ap and the observation axis Ao is greater than or equal to 20 °.
    Furthermore, the various elements of the training system 1 are arranged mutually so that the floating image is formed in a zone separate from the projector 10, and in particular a zone distinct from the return structure 13. In other words, the elements of the training system 1 are positioned and oriented with respect to one another so that the floating image is not superimposed on the return structure 13 of the projector 10. The floating image is thus located at a distance of the return structure 13.
    In general, the system 1 for floating image formation comprises a housing (not shown) inside which are located the image source 11 and the optical projection system 12, and which forms a base on which the display screen 20 and the semi-reflecting structure 30 rest. The housing has an opening at the level of which the return structure is located, thus allowing the light beams emitted by the image source 11 to be reflected by the return structure 13 out of the housing, towards the display screen 20.
    FIG. 7A illustrates a system 1 for forming a floating image according to another embodiment, and FIG. 7B illustrates a variant of the system 1 for forming allowing the formation of a quasi-three-dimensional floating image.
    Referring to FIG. 7A, the system 1 for floating image formation here comprises two devices 1a, 1b, called elementary, for floating image formation, each elementary device being similar or identical to the system 1 for forming a floating image illustrated in fig. 6B.
    The image forming system 1 thus comprises two display faces 20a, 20b distinct from each other, each associated with a semi-reflecting face 30a, 30b and with an optical projection system (not represented). The display faces 20a, 20b are here two separate display screens. Similarly, the semi-reflecting faces 30a, 30b are separate semi-reflecting structures. The display faces 20a, 20b and the semi-reflecting faces 30a, 30b are here substantially flat. The display faces 20a, 20b can be in contact with one another, or as illustrated apart from each other.
    The projector 10 here comprises two source images (not shown), provided by the same image source or two separate image sources, as well as at least one, for example two, optical projection systems (not shown) ) which conjugate each source image supplied to the different display face 20a, 20b. It further comprises a return prism 13 formed of an inverted pyramid comprising two reflecting faces 13a, 13b oriented one and the other towards the corresponding display faces 20a, 20b. Source images can be the same or different from each other.
    In operation, each source image is projected by the optical system or systems on the display faces 20a, 20b, which each display a real image of the source image. The real images displayed are diffused, and preferably reflected or even retro-reflected in the direction of the semi-reflecting faces 30a, 30b, so that virtual images of the real projected images are formed by the semi-reflecting faces 30a, 30b. Preferably, the elementary devices 1a, 1b of floating image formation are identical to one another and are arranged mutually so as to have planar symmetry along a plane passing through a vertical axis of reference Aref. Thus, each virtual image appears at the same distance from the display faces 20a, 20b, so that an observer passing from one display screen 20 to the other is able to perceive the floating image located at the same position.
    FIG. 7B illustrates a variant of a system 1 for forming a floating image, which here comprises a plurality of devices 1a, 1b, the ... for forming an image making it possible to form a quasi-three-dimensional floating image , in the sense that an observer will be able to observe the floating image whatever its position around the training system 1. In addition, when the source images show the same object from different viewing angles, the observer can observe the same object from these different viewing angles, depending on its position around the training system 1, thereby strengthening the three-dimensional aspect of the floating image.
    In this example, the display faces 20a, 20b, 20c ... are the faces of the same display screen, common to the various training devices 1a, 1b ..., arranged one at a time. following the others so as to extend continuously around the same Aref reference axis. In the same way, the semi-reflecting faces 30a, 30b, 30c ... are the faces of the same semi-reflecting structure, common to the various training devices, arranged one after the other so as to be extend continuously around the same Aref reference axis.
    In this example, the display faces 20a, 20b, 20c ... and the semi-reflecting faces 30a, 30b, 30c ... form substantially planar surfaces. They present here an axial symmetry around said reference axis, according to a periodicity corresponding to the width of the faces.
    The projector 10 comprises a plurality of image sources (not shown) and a plurality of optical projection systems (not shown) which each combine the image source 11 with one or the other of the faces d display 20a, 20b, 20c ... It further comprises a return prism 13 formed by an inverted pyramid comprising as many reflecting faces 13a, 13b, 13c ... as there are image sources and display faces 20a, 20b, 20c ... Image sources can provide identical or different source images to each other.
    The operation is similar to that described with reference to fig.7A, with the fact that an observer is able to observe the floating image, positioned at the same distance from the different display faces 20a, 20b , 20c .., whatever its position around the floating imaging system 1. This optical effect reinforces the impression of observing a floating three-dimensional or almost three-dimensional image.
    Alternatively, as detailed below with reference to FIG. 8C, the projector 10 may comprise a single source of a single image, associated with a scanning reference device. The image source 11 is then preferably a pico-projector of the type designated in the technique by the acronym LBS (for Light Beam Steering, in English that is to say directed light beam), comprising a fixed laser source associated with a mobile deflection mirror. The mirror is then mobile in rotation according to at least two axes, namely at an angle φ around the reference axis, and at an angle of inclination 0 relative to the reference axis, making it possible to scan the whole. 360 ° screen display faces.
    FIG. 7C illustrates a variant of the floating image forming system 1 shown in FIG. 7B. In this example, each display face 20a, 20b, 20c is further adapted to diffuse the retro-reflected light in a diffusion cone 2a, 2b, 2c. The angular opening of each diffusion cone 2a, 2b, 2c can be asymmetrical, preferably wide in a horizontal plane and narrow in a vertical plane. This asymmetry of diffusion makes it possible to favor diffusion in the plane of rotation of the observer, around the Aref reference axis. The diffusing and retro-reflecting portions 22 are advantageously adapted so that the diffusion cones 2a, 2b, 2c of the adjacent display faces 20a, 20b, 20c are advantageously partially overlapping two by two, in a horizontal plane orthogonal to the Aref axis. More precisely, the diffusion indicator associated with a display face 20a is advantageously secant from the diffusion indicator associated with the adjacent display face 20b. This enhances the three-dimensional aspect of the floating image while preserving the light efficiency of the system.
    Figures 8A and 8B illustrate a same system 1 for floating image formation according to another embodiment, in which the display screen 20 and the semi-reflective structure 303057731 30 are curved and coaxial, making it possible to reinforce the impression of observing a quasi-three-dimensional floating image.
    The display screen 20 has a curved display face, and forms a cone of revolution, said to be external, around the Aref reference axis. The display face corresponds to the internal face 20i or to the external face 20e of the display screen 20 (cf. fig. 3A and following). The semi-reflecting structure 30 has a curved semi-reflecting face, and also forms a cone of revolution, said to be internal, around the same Aref reference axis. The display screen 20 and the semi-reflecting structure 30 thus extend continuously around the same reference axis Aref, and have the same inclination towards one another, whatever the angular position around the axis.
    The projector 10 includes an image source (not shown). The image supplied is preferably an anamorphic image, or anamorphosis, that is to say an image distorted in the plane of the emission face of the image source so that the visual significance of the image source is not recognizable at the emission face, whereas it becomes so when we observe the corresponding floating image.
    It further comprises an optical projection system (not shown), suitable for ensuring the optical conjugation of the image source and the display screen 20. It finally comprises a return structure 13 has a face reflective, or a set of faces, with axial symmetry around the reference axis. The reflecting face 13 is adapted to reflect the beams transmitted by the optical projection system in the direction of the display screen 20 over 360 °.
    In operation, the image source 11 provides an anamorphic image which is projected by the optical system, and reflected by the conical reflecting mirror 13, at 360 °, on the conical display screen 20. This screen 20 displays a real projected image of the image supplied, which remains anamorphic. The actual image displayed is diffused, and preferably retro-reflected, in the direction of the conical semi-reflecting structure 30, which then forms a virtual image of the actual image displayed. The virtual image therefore appears to float on top of the scene, and is observable whatever the position of the observer around the display training system 1. The floating image then presents the visual meaning which was not detectable at the level of the image supplied anamorphic. Thus, the actual displayed image having no visual significance, the observer is less embarrassed by the possible observation thereof. His attention is then more focused on the floating image.
    FIG. 8C illustrates a variant of the floating image forming system 1 illustrated in FIGS. 8A and 8B, and is essentially distinguished from it in that the headlight 10 comprises, not a fixed return structure, that is to say stationary, but a return face 13 movable in rotation about the axis of Aref reference.
    The return face 13 is here substantially planar and inclined at an angle 0 with respect to the reference axis Aref so as to orient the light beams coming from the image source in the direction of the display screen 20.
    Thus, the image source provides an image to be projected, anamorphic or not, which is projected by the optical projection system on the display screen 20 by means of the rotating reflecting mirror 13. The rotating deflection mirror 13 rotates at the angular speed φ (ί) so that the image supplied is projected 360 ° on the display screen 20. The actual image displayed is then diffused and preferably retro-reflected by the display screen 20 in the direction of the semi-reflecting structure 30 which then forms a floating image.
    As a variant, the projector 10 may comprise a device for projecting scanning images, for example a miniaturized scanning video projector. The device is positioned so as to illuminate the rotating face of the mirror, so that the beam reflected by the mirror illuminates the display face of the screen. The device comprises for example a mobile laser source. By way of example, the device is a pico-projector of the type designated in the technique by the acronym LBS (for Light Beam Steering, in English that is to say directed light beam), comprising a fixed laser source and the movable mirror. The mirror is then movable in rotation along at least two axes, along the angle φ around the reference axis, and along the angle Θ, making it possible to scan the entire display face of the screen.
    Particular embodiments have just been described. Different variants and modifications will appear to those skilled in the art.
    Thus, the positioning and tilting arrangement of the elements of the image forming system can be chosen so that the observation of the floating image is done along a substantially horizontal axis or in low-angle. This reduces the tilt of the display screen and the semi-reflective structure vis-à-vis the reference axis.
    权利要求:
    Claims (14)
    [1" id="c-fr-0001]
    1. System for forming (1) a floating image, comprising:
    o at least one image projector (10), adapted to project a source image; o a display screen (20) adapted to display the image projected by the image projector (10);
    characterized in that said display screen comprises transparent portions (21) and diffusing portions (22), being further adapted to partially transmit incident light beams, o and in that the system (1) comprises in addition to a semi-reflecting structure (30) arranged between the image projector (10) and the display screen (20), comprising a so-called transmission face (30t) adapted to transmit light beams coming from the projector image (10) and light beams coming from a scene to be observed, and an opposite face called reflection (30r) adapted to reflect light beams coming from the display screen (20), so as to form an image virtual, called floating, of the image projected on the display screen (20), said floating image being observable through the display screen (20) by means of the semi-reflecting structure (30).
    [2" id="c-fr-0002]
    2. System (1) according to claim 1, in which the diffusing portions (22) of said display screen (20) are also reflecting so that the light beams coming from the semi-reflecting structure (30) and scattered by the diffusing portions (22) are reflected towards the semi-reflecting structure (30).
    [3" id="c-fr-0003]
    3. System (1) according to claim 1 or 2, in which the diffusing portions (22) of said display screen (20) are also retro-reflecting so that the light beams coming from the semi-reflecting structure (30 ) with an axis of incidence vis-à-vis the diffusing portions (22) are reflected by the diffusing portions (22) in the direction of the semi-reflecting structure (30) with an axis of reflection identical to the axis of incidence.
    [4" id="c-fr-0004]
    4. System (1) according to any one of claims 1 to 3, in which the display screen (20) comprises a plurality of display faces (20a, 20b) substantially planar and distinct in pairs, and wherein the semi-reflecting structure (30) also comprises a plurality of faces (30a, 30b) substantially planar and inclined in pairs, each being optically associated with a display face (20a, 20b).
    [5" id="c-fr-0005]
    5. System (10) according to claim 4, wherein said faces (20a, 20b; 30a, 30b) extend continuously around an axis called reference passing through a return structure (13) of said projector (10) , the display screen (20) and the semi-reflecting structure (30) each forming a pyramid cone.
    [6" id="c-fr-0006]
    6. System (1) according to claim 4 or 5, in which the projector (10) is adapted to provide a plurality of source images, and comprises at least one optical projection system (12a, 12b) adapted to optically combine a source image to a face (20a) different from the display screen (20).
    [7" id="c-fr-0007]
    7. System (1) according to any one of claims 4 to 6, in which the projector (10) comprises a deflection structure (13) having a plurality of reflecting faces (13a, 13b), each of said reflecting faces (13a , 13b) of reference being optically associated with a source image and with a display face (20a, 20b).
    [8" id="c-fr-0008]
    8. System (1) according to any one of claims 4 to 6, wherein the projector (10) comprises a deflection structure (13) having a reflecting face movable in rotation about a reference axis (Aref) of so as to project a source image on said faces (20a, 20b) of the display screen (20).
    [9" id="c-fr-0009]
    9. System (1) according to any one of claims 4 to 8, in which the diffusing portions (22) of said display faces (20a, 20b) are:
    - retro-reflecting so that the light beams coming from the semi-reflecting structure (30) with an axis of incidence with respect to the diffusing portions (22) are reflected by the diffusing portions (22) in the direction of the semi-reflecting structure (30) with an axis of reflection identical to the axis of incidence, and
    - suitable for diffusing retro-reflected light beams in a diffusion cone (2a, 2b), each diffusion cone (2a) associated with a display face (20a) being partially covering the diffusion cone (2b) associated with an adjacent display face (20b).
    [10" id="c-fr-0010]
    10. System (1) according to any one of claims 1 to 3, in which the display screen (20) and the semi-reflecting structure (30) each have a single substantially curved face.
    [11" id="c-fr-0011]
    11. System (1) according to claim 10, in which said curved faces extend continuously around a reference axis (Aref) passing through a return structure (13) of said projector (10), the screen of display (20) and the semi-reflecting structure (30) each forming a cone of revolution with respect to said reference axis.
    [12" id="c-fr-0012]
    The system (1) according to claim 10 or 11, wherein the image provided by the image source (11) is an anamorphic image.
    [13" id="c-fr-0013]
    13. System (1) according to any one of claims 1 to 12, wherein the transparent portions (21) of the display screen (20) are adapted to transmit
    5 light beams coming from the semi-reflecting structure (30), and in which the diffusing portions (22) are adapted to diffuse light beams coming from the semi-reflecting structure (30) towards said semi-reflecting structure (30 ).
    [14" id="c-fr-0014]
    14. System (1) according to any one of claims 1 to 13, in which each
    10 diffusing portion (22) is surrounded by a transparent portion (21), and in which the display screen (20) has a rate of occlusion by the diffusing portions (22) less than or equal to 20%.
    1/7 A1 ^
    AT 5
    A3
    A2
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    同族专利:
    公开号 | 公开日
    JP2019533829A|2019-11-21|
    US20190235375A1|2019-08-01|
    EP3526965A1|2019-08-21|
    US10935879B2|2021-03-02|
    JP6987855B2|2022-01-05|
    EP3526965B1|2020-11-04|
    FR3057731B1|2018-12-07|
    WO2018069625A1|2018-04-19|
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    法律状态:
    2017-10-31| PLFP| Fee payment|Year of fee payment: 2 |
    2018-04-20| PLSC| Publication of the preliminary search report|Effective date: 20180420 |
    2018-10-30| PLFP| Fee payment|Year of fee payment: 3 |
    2019-10-31| PLFP| Fee payment|Year of fee payment: 4 |
    2020-10-30| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1659887A|FR3057731B1|2016-10-13|2016-10-13|SYSTEM FOR FORMING A FLOATING IMAGE|
    FR1659887|2016-10-13|FR1659887A| FR3057731B1|2016-10-13|2016-10-13|SYSTEM FOR FORMING A FLOATING IMAGE|
    PCT/FR2017/052769| WO2018069625A1|2016-10-13|2017-10-10|System for forming a floating image|
    EP17786989.8A| EP3526965B1|2016-10-13|2017-10-10|System for forming a floating image|
    JP2019519366A| JP6987855B2|2016-10-13|2017-10-10|Floating image formation system|
    US16/340,452| US10935879B2|2016-10-13|2017-10-10|System for forming a floating image|
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