P-point autostereoscopic display screen designed to display an I-point autostereoscopic image and display device comprising such a screen

Abstract

AUTOSTEREOSCOPIC DISPLAY SCREEN WITH P VIEWPOINTS INTENDED TO DISPLAY AN AUTOSTEREOSCOPIC IMAGE WITH I VIEWPOINTS AND DISPLAY DEVICE COMPRISING SUCH A SCREEN The invention relates to a display screen with P viewpoints, P being an integer greater than or equal to 6, intended to display an autostereoscopic image with I viewpoints, I being an integer greater than or equal to 2, less than or equal to P / 3, said screen comprising: a matrix (10) of pixels arranged by rows and by columns;an optical network configured so that the P viewpoints of the screen can be perceived successively in lobes, each covering I times the mean interpupillary distance of an observer (8), and so that the screen viewpoints of each pair of viewpoints visible to the observer are separated by at least T buffer viewpoints, T being greater than or equal to 2, such that it is possible to display successively for each lobe, each of the I image viewpoints, repeated each P / I times, and that each viewpoint visible to the observer can be framed by at least 2 buffer viewpoints each displaying that same image viewpoint. Figure for the abstract: Figure 2;

Description

Title of the invention: AUTOSTEREOSCOPIC DISPLAY SCREEN WITH P VIEWPOINTS FOR DISPLAYING AN AUTOSTEREOSCOPIC IMAGE WITH I VIEWPOINTS AND DISPLAY DEVICE COMPRISING SUCH A SCREEN 1. Technical field of the invention

[0001] The invention relates to an autostereoscopic display screen for an autostereoscopic image and a display device comprising such a display screen. The invention also relates to a method for displaying an autostereoscopic image on such a display screen. 2. Technological background

[0002] Autostereoscopy is a technique that allows the display of three-dimensional images without requiring the observer to wear special glasses. This technique is known in itself, in particular from patent documents WO2006 / 024764, WO2014 / 041504, WO2013 / 140363, WO2014 / 016768 in the name of the applicant.

[0003] Generally speaking, an autostereoscopic image consists of a plurality of nested elementary images, each corresponding to views of the same object or scene from different viewpoints. A selector device, typically consisting of a network of cylindrical lenticles or a parallax barrier, is positioned in front of the display screen so as to allow the projection of a pair of elementary images corresponding to two different viewpoints of the scene, respectively towards the two eyes of the observer, thus creating an impression of depth in the observer's brain.

[0004] A display screen for an autostereoscopic image with P viewpoints typically comprises a matrix of pixels arranged in rows and columns, each pixel being composed of a plurality of sub-pixels of different colors. The screen is further surmounted by a selector device (also referred to throughout the text as an optical device), such as an array of identical cylindrical lenticules, each having a focal length configured to reflect light rays from the screen to infinity. The spacing of the cylindrical lenticule array is precisely calculated so that the observer sees, at a predetermined distance from the screen (called the flat tint distance), the images succeeding one another at regular intervals, thanks to the magnifying effect of the lenticule array.

[0005] This magnifying effect results from the fact that a lens placed at the correct distance (its focal length) magnifies the sub-pixel that is aligned with its optical center and the pupil of the observer's eye. If the lens magnifies P times, the sub-pixel seen through the lens is perceived as P times larger than it actually is and masks for the eye which receives the light through this lens the other P sub-pixels which are not in the alignment described previously.

[0006] The cylindrical lenticule network thus forms a viewpoint selector device configured to allow the projection of a pair of differentiated viewpoints into the observation space of the screen, corresponding to two different viewpoints of the scene, respectively towards the two eyes of the observer.

[0007] When certain elements of the two images observed respectively by the left and right eyes of an observer exhibit no disparity (defined as the difference, measured in pixels or sub-pixels, observable and / or measured between the left and right images), these elements perfectly overlap and are perceived on the screen plane itself. Conversely, when there is a disparity between the observed elements, they appear to pop out of the screen or, on the contrary, are perceived as having depth. By convention, depth corresponds to a positive disparity, while pop-out corresponds to a negative disparity. The absolute value of the offset between the two images is the same in both cases, but when the disparity is negative, the pop-out elements of the left image are to the right of those of the right image, and vice versa. It is this offset that produces a pop-out effect (the two eyes converge in front of the screen).Conversely, when the disparity is positive, the depth elements of the left image are to the left of those of the right image and vice versa (both eyes converge at the back of the screen).

[0008] An object the size of a point is perceived as being further from the screen plane the greater the offset on the horizontal plane of this point between the left image and the right image.

[0009] Current autostereoscopic screens face limitations in terms of depth and pop-out that can be achieved without loss of quality. These screens allow the projected content to be inscribed within a viewing cube whose depth is approximately equal to the screen's diagonal. The screens are generally used in such a way that one-third of the viewing cube pops out of the screen and the remaining two-thirds are perceived in depth, behind the screen plane.

[0010] For example, on a 24" screen, this means that the standard viewing cube can have a total amplitude of about 60 cm, with a comfortable pop-out 20 cm in front of the screen and backgrounds 40 cm behind the screen.

[0011] These depth and burst limits are explained by physiological constraints of the observer, by technological constraints and by image processing constraints.

[0012] The physiological constraints result from the fact that each eye of the observer sees a different image in order to form a stereoscopic pair which it merges into converging its gaze where the disparity seems to place the objects in space.

[0013] The disparity between the left and right images induces three different modes of convergence:

[0014] When the observer perceives an object in depth behind the screen, the left eye looks more to the left and the right eye more to the right. Thus, the two optical axes intersect behind the screen, where the observed virtual object is located.

[0015] when the observer perceives an object on the same plane of the screen, both eyes look at the same place on the screen,

[0016] When the observer perceives an object popping up in front of the screen, the left eye looks more to the right and the right eye more to the left. Thus, the two optical axes intersect in front of the screen, where the observed virtual object is located.

[0017] When objects are perceived as depth or as popping out, the gaze converges at different distances from the screen plane. This necessarily leads to a dissociation between the different convergences described above and accommodation, which must correspond to the effort of each eye to see the images clearly at the screen distance.

[0018] The further an object is from the screen plane, the greater the effort required to dissociate the convergence plane from the physical screen plane where the eyes accommodate. However, observers are not all equally capable of the eye movements necessary to perform this dissociation. Only experience and training allow for the effortless dissociation of vergence and accommodation. Without practice, objects may appear blurry, or even doubled, when one converges far from the screen surface and binocular fusion becomes difficult. As in the physical world, the eyes seek sharpness at the distance at which they converge and where the virtual objects are located, even though the two images never leave the physical surface of the screen.

[0019] The technological constraints result from the fact that it is technically complicated to simultaneously display several images on an auto stereoscopic screen and to separate them perfectly for each eye.

[0020] Indeed, as previously stated, an autostereoscopic screen consists of a screen and an optical system placed on its surface. Through a magnifying effect, this optical system subdivides the screen's field of view into contiguous zones, each specifically reserved for a different image. To see in 3D, these images must, at a minimum, form a stereoscopic pair. Displaying only one pair from two images is generally insufficient, and most of the screens offered by the applicant display a series of eight images simultaneously, stereoscopic in pairs. The space formed by the eight contiguous zones occupied by each of these eight images is designated by the term "lobe," which the optical system... This allows for periodic repetition. The succession of viewpoints always occurs in the same order. This repetitive display allows the lobes to repeat without the lenticular network becoming too defocused, over an angle of approximately 100°.

[0021] Achieving perfect separation of the displayed information within each contiguous area of ​​a lobe remains a challenge. Indeed, the light from the screen's backlighting passes through numerous materials before reaching the observer's eye. Some of the light passing through each of these different materials is slightly deflected from its ideal path. Furthermore, to limit the diffusion of the emitted light, the screen and lens array surfaces must be perfectly polished and free of any internal inhomogeneities, such as the frosting within the material itself, which is common for obtaining anti-reflective surfaces. Every micro-imperfection is likely to deflect the light and disrupt the refractive effect of the microlenses designed to separate the viewpoints.The shape of the pixels and the fact that the optical axis of the lenses can simultaneously intersect sub-pixels assigned to different viewpoints can prevent this compartmentalization.

[0022] Image processing constraints arise from the fact that computer processing options depend on a number of parameters, including the number of viewpoints, their repetition, the lobe width, the observation distance, and the number of simultaneous observers. Sometimes, the screen or computer electronics apply subtle modifications to the content of the images to be displayed, which has the effect of altering their precise location. For example, by changing the intensity of an entire pixel, its three subpixels are affected simultaneously, thus affecting three viewpoints at once (in the case where only one subpixel is used per image viewpoint).

[0023] The applicant has already proposed a system equipped with an observer head tracking device (more commonly known as a "tracking" device) to display in real time the viewpoints to be addressed to each eye of the observer. The speed and accuracy of the tracking are all the more critical when the objects are far from the screen plane. A minute head movement then results in a significant apparent displacement of the objects, particularly when the objects are very deep, which is one of the objectives of the invention.

[0024] The inventors therefore sought a solution that would overcome at least some of the aforementioned constraints. 3. Objectives of the invention

[0025] The invention aims to provide an autostereoscopic display screen that makes it possible to overcome the limits of pop-out and depth achievable by known autostereoscopic screens.

[0026] The invention aims in particular to provide a screen with almost perfect resolving power, which gives the observer the possibility of perceiving the volume in bursting up to half the distance of the flat tint and that in depth up to several meters behind the plane of the screen, without there being any real limit, while maintaining optimal sharpness of the display for each eye, despite the significant disparity that it is necessary to inscribe in the content to achieve this.

[0027] The invention aims in particular to provide a display screen which makes it possible to multiply the relief performance of known screens while maintaining, or even improving, the quality of the observed image.

[0028] The invention aims in particular to provide a display screen for an autostereoscopic image which has a greater resolving power than known screens.

[0029] The invention also aims to provide a display screen that limits interference between the viewpoints visible to each eye of the observer.

[0030] The invention also aims to provide a stereoscopic auto display device which includes a display screen according to the invention.

[0031] The invention finally aims to provide a method for displaying an autostereoscopic image on an autostereoscopic display screen according to the invention. 4. Description of the invention

[0032] To this end, the invention relates to an autostereoscopic display screen with P viewpoints, referred to as screen viewpoints, P being an integer greater than or equal to 6, intended to display an autostereoscopic image with I viewpoints, referred to as image viewpoints, I being an integer greater than or equal to 2, less than or equal to P / 3, preferably equal to 2, said screen comprising:

[0033] a matrix of pixels arranged by rows and columns, each pixel being composed of a plurality of sub-pixels of different colors, intended to display each one sub-pixel from one of the image viewpoints,

[0034] a network of cylindrical lenticles or a parallax barrier, called an optical network, configured to allow the projection of 1-1 pairs of predetermined screen viewpoints to the eyes of an observer located at a nominal distance from the screen, called the flat tint distance.

[0035] The screen according to the invention is characterized in that said optical array is configured so that the P viewpoints of the screen can be perceived successively in a direction, called the horizontal direction, by said observer at said flat tint distance, in spaces in front of the screen, called lobes, each covering I times the average interpupillary distance of an observer, and so that the screen viewpoints of each pair of viewpoints visible to the observer at the flat tint distance are separated by at least T screen viewpoints, called buffer viewpoints, T being greater than or equal to 2, such that it is possible to display successively for each lobe, each of the I image viewpoints, repeated each P / I times, and that each viewpoint visible to the observer at the flat tint distance can be framed by at least 2 buffer viewpoints each displaying that same image viewpoint.

[0036] A display screen according to the invention therefore has the particularity of being equipped with an optical network, such as a network of cylindrical lenticles (also referred to as an optical component) configured to display P viewpoints, for example 10 viewpoints (in the case where P is equal to 10).

[0037] When the invention uses a single subpixel per viewpoint per lens and per horizontal line, each lens of the lenticular array covers P subpixels on each horizontal line. When the invention uses a single subpixel per viewpoint per lens on L horizontal lines, each lens of the lenticular array covers P / L subpixels on each horizontal line.

[0038] A screen according to the invention makes it possible to obtain a near-perfect resolving power, thanks to the creation of buffer zones formed by duplicating the image viewpoints and isolating from each other the two viewpoints perceived by each of the two eyes. The I image viewpoints form 1-1 successive stereoscopic pairs, and these different viewpoints are separated from each other by buffer zones created by duplicating an image viewpoint. In other words, each of the I screen viewpoints visible to the observer at the flat hue distance and each displaying an image viewpoint is framed by at least 2 buffer viewpoints, each displaying the same image viewpoint.

[0039] In addition, each lobe covering I times the average interpupillary distance of an observer, each of the I image viewpoints benefits from a space corresponding to an interpupillary distance to display the perceived viewpoint and its buffer viewpoints.

[0040] The invention thus goes against the prejudice of those skilled in the art, who generally consider that improving an autostereoscopic system should be achieved by increasing the number of image viewpoints, thereby increasing the lobe width, parallax, and viewing distance in front of and behind the flat color distance, so as to give the viewer greater freedom of positioning. This can be done at the expense of perceived resolution if the screen resolution is not increased proportionally.

[0041] The invention does not seek to give the viewer greater latitude in positioning but rather to liberate the volume he perceives. To this end, it tends to fix his position, so as to limit as much as possible the number of image viewpoints required, only two being sufficient, in order to obtain an almost perfect resolving power and to make possible the perception of unusually deep volumes.

[0042] The invention makes it possible to create a monocular sub-lobe per image viewpoint, equal in width to the reference interpupillary distance (approximately 6.5 cm), and to produce in this monocular sublobe means to display the same image multiple times, so that each instance of this image is visible over a width equal to the monocular sublobe divided by the number of times the image is duplicated.

[0043] In the absence of the invention, and when the content is pushed far in front of or behind the screen plane, the disparity is very significant and the problem of ghosting is particularly acute. The image seen by each eye is likely to retain a vestige of the image intended for the other eye. Consequently, the left eye sees not only the left image intended for it, but also the ghost of the right image, and conversely, the right eye sees not only the right image intended for it, but also the ghost of the left image. However, the ghost of the right image seen in the left image pairs stereoscopically with the right image itself, while the ghost of the left image seen in the right image pairs stereoscopically with the left image itself, which positions the ghosts on the screen plane itself, and not at the edges of the elements in depth.

[0044] With the invention, viewpoints close to those observed by the observer's eyes come from the same image, which makes crosstalk between them imperceptible.

[0045] Since the images intended for the observer's eyes are each replicated several times (at least two replicas to form at least three identical successive viewpoints, including the viewpoint observed by the observer's eye), each subpixel magnified by a lens for one eye is surrounded by subpixels belonging to the same image. Thus surrounded by its peers, a subpixel can no longer interfere with the one intended for the other eye. If it does interfere with its immediate neighbors, this is not noticeable.

[0046] A display screen according to the invention therefore has the particularity of allowing the display of T buffer viewpoints between the viewpoints dedicated respectively to the left eye and the right eye of the observer.

[0047] A screen according to the invention not only provides near-perfect separation power, but also offers the advantages of traditional multi-view content, namely:

[0048] the possibility of moving away from the flat tint distance through the recombination of viewpoints;

[0049] the proportional increase in the lobe and therefore in the space in which the spectator can place his eyes;

[0050] the parallax effect obtained when moving horizontally along the screen;

[0051] the guarantee that any remaining ghosting, in the case of very strong contrasts and extreme disparities for example, is perceived at the edge of objects and not on the plane of Image collimation. This is an undeniable advantage for applications that require the implementation of renderings conducive to the perception of ghosting.

[0052] Preferably, the optical network of a screen according to the invention is formed of cylindrical lenses, each of which has a principal axis that forms an angle α with the direction of the columns.

[0053] Various inclinations of the optical grating (between vertical and 45°) can be used provided that a suitable grid for distributing the viewpoints is defined. For example, it is possible to use a grating whose lenses are inclined at an angle α of 9.46°, 18.43°, 26.56°, or 33.69°, as shown in the figures discussed later.

[0054] According to a particularly advantageous embodiment of the invention, I is equal to 2 and said optical network is configured to be able to display in each lobe, M times the image viewpoint dedicated to the left eye of the observer and N times the image viewpoint dedicated to the right eye of the observer, M and N each being greater than or equal to 3 and their sum being equal to P, and forming T buffer viewpoints between the viewpoint dedicated to the left eye and the viewpoint dedicated to the right eye.

[0055] This advantageous variant relates to a screen intended to display an autostereoscopic image at 2 viewpoints intended respectively for the right eye and the left eye of the observer.

[0056] In this preferred case of displaying an autostereoscopic image from 2 viewpoints (1=2), the screen is controlled to display only two different images intended respectively for the left and right eyes of the observer. In other words, each image is repeated several times for each eye, in this case M times for the left eye and N times for the right eye, M and N each being an integer greater than or equal to 3 and their sum being equal to P.

[0057] In addition, the optical parameters of the optical component are chosen so that the P viewpoints (M viewpoints for the left eye and N viewpoints for the right eye) cover a lobe which extends over a distance equal to twice the average interpupillary distance of an observer, i.e. in practice a distance of the order of 13 cm (the average interpupillary distance of an adult being 6.5 cm).

[0058] Thus, and in the case where P is equal to 10 and I is equal to 2, a change of screen viewpoint occurs, at the flat tint distance, every 1.3 cm.

[0059] The display screen according to this variant can be designed such that the number of screen viewpoints intended to display the image viewpoint dedicated to the left eye of an observer located at the flat hue distance is equal to or different from the number of screen viewpoints intended to display the image viewpoint dedicated to the observer's right eye. In other words, the screen can be designed to obtain a symmetrical arrangement (M and N are then equal) or an asymmetrical arrangement (M and N are then different from each other) viewpoints dedicated to each of the two eyes of the observer.

[0060] Preferably, M and N are equal and the screen allows a symmetrical display of the viewpoints dedicated respectively to the left eye and the right eye of the observer.

[0061] That being said, it is also possible to exploit an asymmetrical arrangement and minimize its drawbacks by taking into account the direction of the observer's head movement to position the greatest number of buffer viewpoints in the area of ​​the lobe toward which the eyes are moving, and by dynamically optimizing the allocation of viewpoints predictively, by performing permutations in parts of the lobe not perceived by the observer's eyes. This requires the use of a device for detecting the position of the observer's head, as discussed later in connection with the device according to the invention.

[0062] Preferably and according to this variant, the screen is further designed so that the sum of the number of viewpoints to the left of the left eye and the number of viewpoints to the right of the right eye is equal to the number of buffer viewpoints T separating those perceived by the two eyes of the observer.

[0063] This allows for the same number of successive buffer T viewpoints to be available on each side of both eyes.

[0064] According to a particular embodiment of the variant of the invention with 2 image viewpoints (I equals 2), P is equal to 10 so that the screen presents 10 screen viewpoints and said optical array is configured so that the pairs visible to the observer at the flat tint distance are the views 1-6, 2-7, 3-8, 4-9, 5-10 for screen viewpoints numbered successively from 1 to 10 so that each subpixel perceived by each eye of the observer can be surrounded on each side by 2 buffer viewpoints.

[0065] Thus, and in the case where P is equal to 10 and M and N are each equal to 5, the viewpoints perceived by each eye are always separated by 4 other viewpoints, which serve as a buffer and avoid interference.

[0066] Thus, when the right eye perceives viewpoint no. 3, the left eye perceives viewpoint no. 8. This viewpoint no. 3 is framed on its left by viewpoints no. 1 and no. 2 and on its right by viewpoints no. 4 and no. 5, while viewpoint no. 8 is framed on its left by viewpoints no. 6 and no. 7 and on its right by viewpoints no. 9 and no. 10. In this scenario, the two viewpoints perceived by the observer are isolated from each other by four buffer viewpoints, which prevents interference. The resolving power is therefore optimal for the screen according to this preferred embodiment of the invention.

[0067] According to a particular embodiment of the variant of the invention with 2 image viewpoints (I equals 2), M and N are odd such that each viewpoint image dedicated to each eye of the observer can be surrounded, in each lobe, by the same number of buffer viewpoints.

[0068] For example, and in the case where M and N each have a value of 5 (forming a 10-viewpoint screen), the encoding of the autostereoscopic image content relies on encapsulating a stereoscopic pair in a 10-viewpoint image format. Each subpixel perceived by an eye is framed by four buffer subpixels, two to its left and two to its right, which display the same image. Interference from neighboring subpixels with the perceived viewpoint is invisible since they all display the same image.

[0069] Image decoding is performed using a lenticular grating whose innovative architecture, with 10 viewpoints, allows for a change of viewpoint every 1.3 cm. The average interpupillary distance being 6.5 cm, it allows for the insertion of 4 buffer viewpoints between the left and right viewpoints, as required by the content. The lobe of this grating is 13 cm at the flat tint distance (twice the interpupillary distance). This also makes it possible to accommodate pupillary distances that differ from the chosen average value of 6.5 cm, which in this case results in a modification of the ideal symmetry.

[0070] The invention can be implemented using different pixel matrices. For example, it is possible to use a pixel panel with horizontal sub-pixels (i.e., sub-pixels superimposed vertically) or a pixel panel with vertical sub-pixels (i.e., sub-pixels juxtaposed horizontally), or even an organic light-emitting diode (OLED) panel or an active-matrix organic light-emitting diode (AMOLED).

[0071] In the particular case of a slab formed of horizontal sub-pixels, each pixel of the pixel matrix is ​​composed of a plurality of sub-pixels of different colors superimposed on each other in the direction of the columns.

[0072] For 2D display, the vertical or horizontal orientation of the subpixels has no impact on the user, who perceives no difference in the display depending on the screen orientation. The information is always encoded at the pixel level, and the arrangement of its substructure has no impact on the display quality.

[0073] On the other hand, for a 3D display, when a lenticular network acting by magnifying effect is glued to the surface of the screen, the orientation of the sub-pixels and the regularity of their geometry becomes crucial.

[0074] When using a screen in landscape mode whose subpixels are vertically aligned in portrait mode, or when using pixel panels with anisotropic pixel structure, the cylindrical microlenses of the lenticular array cannot They can no longer discriminate colors separately and must align entire pixels. An entire pixel then becomes the smallest entity that the lenses can allow to be observed individually by magnifying effect.

[0075] The invention also relates to a device for displaying an autostereoscopic image at I viewpoints, called image viewpoints, comprising:

[0076] a display screen according to the invention,

[0077] a display module configured to display for each lobe, each of the I image viewpoints, repeated each P / I times, each viewpoint visible to the observer at the flat tint distance being framed by at least 2 buffer viewpoints each displaying that same image viewpoint.

[0078] The advantages and technical effects of a display screen according to the invention apply mutatis mutandis to a display device according to the invention.

[0079] According to the invention, the display module is configured to assign to each sub-pixel of the pixel matrix of the display screen, a sub-pixel of one of the I images intended for the observer's eyes. This display module is preferably formed by a computer device for controlling the pixel matrix.

[0080] Throughout the text, the term module means a software element, a subset of a software program, which can be compiled separately, either for independent use or to be assembled with other modules of a program, or a hardware element, or a combination of a hardware element and a software subprogram.

[0081] Preferably, the display module of a device according to the invention is a subset of a software program intended to be executed by a computer or by a microprocessor connected to the display screen.

[0082] According to a particularly advantageous variant, I is equal to 2 and said display module is configured to display in each lobe formed by said display screen, M times the image viewpoint dedicated to the left eye of the observer and N times the image viewpoint dedicated to the right eye of the observer and forming T buffer viewpoints, between the image viewpoint dedicated to the left eye and the image viewpoint dedicated to the right eye.

[0083] In the preferred case where I equals 2, these 2 viewpoints are intended respectively for the left and right eye of an observer. In the case where I is greater than 2, the 1-2 central viewpoints can be seen either by the left eye or by the right eye of an observer, depending on its position.

[0084] Advantageously and according to the invention, the device further comprises a device for detecting, at every instant, the position of the observer's head relative to said horizontal and / or vertical direction so as to allow said display module to slide the image viewpoints in each lobe such that said screen viewpoints visible to the observer are permanently framed by buffer viewpoints of the image viewpoint visible to that eye.

[0085] A display device according to this embodiment allows the observer to be permanently positioned at the center of the lobe so that they perceive (in the case where 1=2 and N=M=5 to form 10 screen viewpoints, P=10) viewpoints No. 3 and No. 8. A lobe of twice the interpupillary distance (i.e., on the order of 13 cm) offers limited latitude of movement. Rather than forcing the observer to position themselves at the center of the lobe, the invention allows the lobe to be dynamically calibrated to center it on the observer's position, thanks to a tracking device (also known as "tracking") of the observer's head.

[0086] The invention thus makes it possible to identify the position of the observer's head relative to the horizontal and / or vertical direction of the screen (i.e., to detect the lateral movements of the observer's head relative to the screen in the case of horizontal detection) and to slide the viewpoints within the lobe so as to present viewpoints No. 3 and No. 8 to the observer. Since the objective in this embodiment is solely to locate the position of the observer's face relative to the horizontal and / or vertical direction, a simple 2D camera is sufficient to track the observer's head.

[0087] According to one embodiment of the invention, said detection device is configured to detect, at each instant, the position of the observer's head - in particular of each eye of the observer - with respect to a predetermined point on the display screen, allowing the X, Y, Z coordinates of each eye of the observer to be defined with a predetermined precision, in an orthonormal frame of which said predetermined point on the screen is the origin of said frame, said screen defining the X and Y axes of this frame and the direction perpendicular to the screen defining the Z axis of this frame.

[0088] According to this variant of the invention, the position of the observer's head is determined at each instant in three dimensions, which makes it possible to use a device according to this variant in augmented reality applications.

[0089] In particular, when the brightness of the screen allows it, it is possible to use the screen, not in direct vision, but in reflection on a semi-reflective mirror, so as to create an augmented reality experience of the type "Pepper's ghost".

[0090] The 3D volume displayed on the screen then materializes in the room and offers the possibility of creating unprecedented immersive experiences, provided that care is taken not to create depth conflicts. In particular, care must be taken to ensure that a deep virtual object does not overlap with an element of the scene located in front of it.

[0091] The vergence / accommodation dissociation then no longer poses a problem because the gaze uses the physical world as a support to converge on the virtual elements which register there.

[0092] When the observer is not too close to the screen, the dioptric difference is small enough that the feeling of sharpness is good and visual fatigue is minimal.

[0093] To be credible, an augmented reality experience must, however, offer a perfect match between the physical and virtual worlds. Beyond the depth-of-field conflicts that must be avoided at all costs, virtual objects superimposed on the real world must obey the same perspective rules and react to the observer's movements in the same way as objects in the room. A virtual cube superimposed on a physical cube must behave in every respect like the real object when the observer moves their head. The parallax between virtual objects perceived by the observer must also remain consistent with the position of their eyes. To achieve this, it is essential to measure, in real time, with low latency and with great precision, the position of each of the observer's pupils in three dimensions.

[0094] The Z-axis measurement is particularly important in this context. Indeed, given the good resolving power of the screen according to the invention and the great depths it allows to be simulated, the displayed disparity produces a very different sensation of volume depending on the distance at which the content is collimated, but also depending on the distance of the observer from the screen. To generate images faithful to the physical world, the real-time image rendering engine must therefore know precisely the Z-position of the observer's pupils, in order to adapt the stereoscopic base and focal length accordingly, and the X and Y positions to adjust the parallax.

[0095] The invention thus makes it possible to know the relative position of the observer with respect to the environment in order to adapt the virtual scene accordingly. In particular, the invention according to this embodiment makes it possible to know the distance at which the observer's pupils are located from the screen, in order to adapt the rendering of the virtual scene and make it consistent with the physical world.

[0096] Such a device can for example be used in a flight simulator, construction equipment driving simulator, teleoperation simulator, or any other simulator aimed at putting the user in hyper-realistic conditions, without requiring the wearing of an augmented reality headset.

[0097] In this particular application context, the room can be empty of objects, and it is no longer essential to maintain consistency between the physical and virtual worlds. However, measuring the Z position of the pupils remains essential for adjusting the stereoscopic base and focal length, just as it is essential in the X and Y directions for adjusting the parallax.

[0098] The invention also relates to a method for displaying an autostereoscopic image at I viewpoints, I being an integer greater than or equal to 2, on a display screen with P viewpoints, called screen viewpoints, P being an integer greater than or equal to 6 and greater than or equal to 31, comprising a matrix of pixels arranged in rows and columns, each pixel being composed of a plurality of subpixels of different colors, intended to display each one subpixel of one of the image viewpoints, and an array of cylindrical lenticles or a parallax barrier, called an optical array, configured to permit the projection of 1-1 pairs of predetermined screen viewpoints to the eyes of an observer situated at a nominal distance from the screen, called the flat tint distance, and so that the P screen viewpoints can be perceived successively in a direction, called the horizontal direction, by said observer at said flat tint distance, in spaces in front of the screen, called lobes,each covering I times the mean interpupillary distance of an observer.

[0099] The method according to the invention is characterized in that it comprises, for each lobe, the assignment to each adjacent screen viewpoint of each image viewpoint visible to the observer at the flat tint distance, of a copy of this image viewpoint such that, in each lobe, each of the I image viewpoints visible to the observer at the flat tint distance is framed by at least 2 buffer viewpoints each displaying this same image viewpoint, and in that it consists of the succession of the I image viewpoints repeated each P / I times.

[0100] The advantages and technical effects of a display screen according to the invention apply mutatis mutandis to a display method according to the invention.

[0101] According to a particularly advantageous embodiment of the invention, I is equal to 2 and the method comprises, for each lobe:

[0102] the assignment to the first M screen viewpoints of the image viewpoint dedicated to the observer's left eye,

[0103] the assignment to the following N screen viewpoints of the image viewpoint dedicated to the observer's right eye,

[0104] M and N each being greater than or equal to 3 and their sum being equal to P.

[0105] The invention also relates to a display screen, a display device and a display method characterized in combination by all or part of the characteristics mentioned above or below. 5. List of figures

[0106] Other objects, features and advantages of the invention will become apparent from the following description, given by way of non-limiting example only, and which refers to the accompanying figures in which:

[0107] • [Fig. 1] is a schematic view of a display screen according to one embodiment of the invention,

[0108] [Fig.2] is a schematic view of a display screen according to one embodiment of the invention with 10 viewpoints screen of a 2 viewpoint image comprising a pixel panel formed of vertical sub-pixels surmounted by an optical array having an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=18.43°),

[0109] • [Fig.3] is a schematic view of the left image arrangement principle and right on a screen according to one embodiment of the invention,

[0110] [Fig.4] is a schematic view of a display screen according to one embodiment of the invention with 9 viewpoints screen of a 2 viewpoint image comprising a pixel panel formed of vertical sub-pixels surmounted by an optical array having an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=9; N=5; M=4; a=18.43°),

[0111] [Fig.5] is a schematic view of a display screen according to an embodiment of the invention with 8 viewpoints, a screen of a 2 viewpoint image comprising a pixel panel formed of vertical sub-pixels and surmounted by an optical array having an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=8; N=4; M=4; a=18.43°),

[0112] [Fig.6] is a schematic view of a display screen according to an embodiment of the invention with 10 viewpoints, a screen of a 2 viewpoint image comprising a pixel panel formed of vertical sub-pixels and surmounted by an optical array having an inclination of 9.46° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=9.46°),

[0113] [Fig.7] is a schematic view of a display screen according to one embodiment of the invention with 10 viewpoints screen of a 2 viewpoint image comprising a pixel panel formed of vertical sub-pixels and surmounted by an optical array having an inclination of 26.56° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=26.56°),

[0114] [Fig.8] is a schematic view of a display screen according to an embodiment of the invention with 10 viewpoints, a screen of a 2 viewpoint image comprising a pixel panel formed of vertical sub-pixels and surmounted by an optical array having an inclination of 33.69° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=33.69°),

[0115] [Fig.9] is a schematic view of a display screen according to one embodiment of the invention with 10 viewpoints screen of a 2 viewpoint image comprising a pixel panel formed of horizontal sub-pixels and surmounted by an optical array having an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=18.43°),

[0116] [Fig. 10] is a schematic view of a display screen according to a 6-viewpoint embodiment of the invention, a 2-viewpoint image screen comprising a pixel slab formed of horizontal sub-pixels and surmounted by an optical array with an inclination of 26.56° with respect to the vertical (in other words, 1=2; P=6; N=3; M=3; a=26.56°),

[0117] [Fig. 11] is a schematic view of a display screen according to an embodiment of the invention with 10 viewpoints, a screen of a 2 viewpoint image comprising a pixel panel formed of horizontal sub-pixels and surmounted by an optical array having an inclination of 33.69° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=33.69°),

[0118] [Fig. 12] is a schematic view of a display screen according to an embodiment of the invention with 20 viewpoints of a 4 viewpoint image screen comprising a pixel panel formed of horizontal sub-pixels and surmounted by an optical array having an inclination of 9.46° with respect to the vertical (in other words, 1=4; P=20; a=9.46°),

[0119] [Fig. 13] is a schematic view of a display screen according to an embodiment of the invention with 20 viewpoints, a screen of a 4 viewpoint image comprising a pixel panel formed of horizontal sub-pixels and surmounted by an optical array having an inclination of 18.43° with respect to the vertical (in other words, 1=4; P=20; a=18.43°),

[0120] [Fig. 14] is a schematic view of a display device according to an embodiment of the invention comprising a screen according to the invention, a tracking device and a display module.

[0121] 6. Detailed description of an embodiment of the invention

[0122] In the figures, scales and proportions are not strictly respected for the purposes of illustration and clarity.

[0123] Figure 1 is a partial schematic view of an autostereoscopic display screen according to the invention, comprising a pixel matrix 10 (also referred to as a pixel panel) arranged in rows and columns, surmounted by an optical grating 11 of cylindrical lenses. The optical grating 11 is shown partially, but it is evident that in practice it extends over the entire pixel panel, or where appropriate, over the portion of the screen dedicated to autostereoscopy.

[0124] The particularity of the screen according to the invention is that the optical network 11 is configured to allow the display of P viewpoints and that the solid angle in which these P viewpoints are spread is I times the interpupillary distance, where I represents the number of viewpoints of the autostereoscopic image to be displayed by this screen.

[0125] For example, for a 10-viewpoint (P=10) display of a 2-viewpoint (1=2) image, the solid angle in which these 10 viewpoints are spread is 13 cm, that is, twice the average interpupillary distance of 6.5 cm at the flat tint distance of the screen.

[0126] In other words, the specific screen proposed by the inventors is equipped with an optical array 11 for displaying P viewpoints. The innovation consists of displaying only I different images on this screen, each replicated a certain number of times. On either side of each subpixel magnified by a lens for one eye are a number of subpixels belonging to the same image. Thus surrounded by its peers, a subpixel can no longer interfere with the one intended for the other eye. If it does interfere with its immediate neighbors, this is not noticeable.

[0127] In the specific case of a 10-viewpoint screen intended to display a 2-viewpoint autostereoscopic image, manufacturing a 10-viewpoint optical array, visible successively in a 13 cm lobe, requires a microlens focal length 5 times longer than that required for a 65 cm lobe (65 cm / 13 cm = 5) as already proposed by the applicant. Long focal length lenses have a proportionally larger radius of curvature and are easier to machine.

[0128] Machining a long-focal-length optical component makes it possible to obtain an almost perfect surface finish after machining and bonding the front face with optical silicone. Furthermore, the imperfections inherent in prior art screens are largely reduced with a screen according to the invention.

[0129] A person skilled in the art will be able to determine, based on the target flat tint distance and the characteristics of the screen, the parameters of the optical array necessary to allow the display of the P viewpoints in lobes of 1x6.5 cm.

[0130] For example, for a 15.6-inch 4K panel, whose display area measures approximately 345 mm x 194 mm and each pixel 0.09 mm, the grid pitch would be approximately 0.299 mm, the focal length of the lenticular grid would depend on the usage conditions and could be 4 mm for a flat tint of 1.30 m (case of 10 viewpoints to display an image at 2 viewpoints)

[0131] 6.1. Embodiment 1=2 : P=10 : N=5 : M=5 : a=18.43° : vertical sub-pixels

[0132] Figure 2 illustrates an embodiment of the invention representing a 10 screen viewpoints to display an autostereoscopic image at 2 viewpoints. The pixel array is formed of vertical sub-pixels and the optical array has an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=18.43°).

[0133] This screen is designed to display, in each lobe, five times the image viewpoint dedicated to the observer's left eye and five times the image viewpoint dedicated to the observer's right eye. In this figure and all those referring to a 2-viewpoint autostereoscopic image, the subpixels assigned to the right eye are represented in gray and the subpixels assigned to the left eye are represented in white.

[0134] In addition, a black frame represents the smallest "modulo", that is, the smallest block of necessary and sufficient data that allows the entire screen to be filled by re periodic petition, with or without vertical and / or horizontal phase shift. The "modulo" is most often inscribed under a single lens but this is not always the case, depending on the angle of the grating and the number of viewpoints.

[0135] Each pixel in the pixel array is composed of sub-pixels of different colors, identified in the figures by the letters R, G and B (for red, green and blue). Each sub-pixel displays a sub-pixel from the viewpoint of the left image (white sub-pixel) or from the viewpoint of the right image (grey sub-pixel).

[0136] Each pixel is formed of an RGB triplet, schematically represented on [Fig.3] by different levels of grey as well as by the letters R, G and B. On [Fig.3], the sub-pixels dedicated to the left eye are surmounted by the letter G and the sub-pixels dedicated to the right eye are surmounted by the letter D.

[0137] Since the angle of the optical grating is 18.43° in this embodiment, its tangent is 1 / 3, and the pixels are square, with each new row of pixels on the screen, the optical axis of the lenses shifts by one-third of a pixel. At 10 viewpoints, the grating spacing is approximately 10 / 3 of a pixel.

[0138] Viewpoints 1 to 5 are dedicated to the right image and viewpoints 6 to 10 to the left image. Thanks to this particular arrangement, viewpoints 3 and 8 each have 2 buffer viewpoints on either side, which display the same image and with which no visible alteration of the perceived image occurs.

[0139] Preferably, the screen is used with a user head tracking device to ensure that viewpoints 3 and 8 are the viewpoints addressed to the observer.

[0140] Thus, the viewpoints perceived by each eye (schematized by circles on [Fig.3] and by a transparency of the lens on [Fig.2]) are separated by 4 other viewpoints, which serve as a buffer for an interpupillary distance of 6.5 cm, or by 3 or 5 other viewpoints when the interpupillary distance is lower or higher.

[0141] 6.2, Embodiment 1=2: P=9: N=5: M=5: a=18.43°: vertical sub-pixels

[0142] Figure 4 illustrates another embodiment of the invention representing a screen with 9 viewpoints for displaying a 2-viewpoint autostereoscopic image. The pixel array is formed of vertical sub-pixels and the optical grating has an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=9; N=5; M=4; a=18.43°).

[0143] In this embodiment, the distribution of viewpoints is not balanced since there is an odd number of screen viewpoints. In the example shown, 5 viewpoints have been assigned to the left eye (represented by white subpixels in [Fig. 4]) and 4 viewpoints to the right eye (represented by gray subpixels in [Fig. 4]). Of course, another distribution of viewpoints could have been chosen for a substantially identical result. Depending on the direction of As the user moves, this distribution can rebalance itself. The eye that moves towards the center of the lobe is favored to give it more viewpoints between the two eyes.

[0144] In this embodiment, viewpoints 1 to 5 are dedicated to the right image and viewpoints 6 to 9 to the left image. Viewpoints 3 and 7 are the screen viewpoints projected towards the two eyes of the observer, and the latter have 3 buffer viewpoints between them.

[0145] 6.3. Embodiment 1=2 : P=8 : N=5 : M=5 : a=18.43° : vertical sub-pixels

[0146] Figure 5 illustrates another embodiment of the invention representing a screen with 8 viewpoints for displaying an autostereoscopic image at 2 viewpoints. The pixel array is formed of vertical sub-pixels and the optical grating has an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=8; N=4; M=4; a=18.43°).

[0147] In this embodiment, viewpoints 1 to 4 are dedicated to the right image (shown in gray) and viewpoints 5 to 8 to the left image (shown in white). Viewpoints 3 and 7 are the screen viewpoints projected towards the observer's two eyes, and the observer has 3 buffer viewpoints between them.

[0148] Of course, other configurations are possible than those shown, both in terms of the number of screen viewpoints and the tilt of the lenticular array.

[0149] 6.4, Embodiment 1=2: P=10: N=5: M=5: a=9.46°: vertical sub-pixels

[0150] Figure 6 illustrates another embodiment of the invention representing a 10-viewpoint screen for displaying a 2-viewpoint autostereoscopic image. The pixel array is formed of vertical sub-pixels and the optical grating has an inclination of 9.46° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=9.46°).

[0151] It differs from the embodiment of [Fig. 2] due to the angle of the optical grating, which requires a viewpoint filling grid adapted to this specific arrangement, and also by a lens pitch that is twice as fine. The viewpoints are out of phase, which results in the "modulo" being spread over 6 lines instead of 2.

[0152] 6.5. Embodiment 1=2 : P=10 : N=5 : M=5 : a=26.56° : vertical sub-pixels

[0153] Figure 7 illustrates another embodiment of the invention representing a screen with 10 viewpoints for displaying a 2-viewpoint autostereoscopic image. The pixel array is formed of vertical sub-pixels and the optical grating has an inclination of 26.56° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=26.56°).

[0154] It differs from the embodiment of [Fig. 2] because of the angle of the optical grating, which implies a viewpoint filling grid adapted to this specific arrangement, but the lens pitch is the same. On the other hand, the "Modulo" is spread out here under three lenses instead of just one. Figure 7 therefore represents these three lenses.

[0155] 6.6. Embodiment 1=2 : P=10 : N=5 : M=5 : a=33.69° : vertical sub-pixels

[0156] Figure 8 illustrates another embodiment of the invention representing a screen with 10 viewpoints for displaying a 2-viewpoint autostereoscopic image. The pixel array is formed of vertical sub-pixels and the optical grating has an inclination of 33.69° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=33.69°).

[0157] Also, the only difference compared to the embodiment of [Fig.4] is the angle of the optical network, which implies a viewpoint filling grid adapted to this specific arrangement.

[0158] 6.7, Embodiment 1=2: P=10: N=5: M=5: a=18.43°: sub-pixels ho rizontaux

[0159] The invention also applies to pixel arrays formed of horizontal sub-pixels.

[0160] Thus, [Fig. 9] illustrates an embodiment of the invention representing a 10-viewpoint screen for displaying a 2-viewpoint autostereoscopic image. The pixel array is formed of horizontal sub-pixels and the optical grating has an inclination of 18.43° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=18.43°).

[0161] In this screen, each pixel of the pixel matrix is ​​composed of a plurality of sub-pixels of different colors superimposed on each other in the direction of the columns and associated with an optical array formed of cylindrical lenses each having a principal axis which forms an angle of 18.43° with the direction of the columns.

[0162] The cylindrical microlenses of the lenticular array can no longer discriminate colors separately and they simultaneously magnify the three RGB components of each pixel. The entire pixel then becomes the smallest entity that the lenses can allow to be observed individually by magnifying effect.

[0163] Furthermore, the three colored dots of a pixel (the sub-pixels) are assembled to form approximately a square. In other words, and according to this variant, the colored dots fit into three small, juxtaposed and superimposed rectangles three times wider than they are high to form a square, the pixel.

[0164] We can clearly see on [Fig.9] that the horizontal sub-pixels are grouped in blocks of three to display each the same viewpoint of the image dedicated either to the left eye (represented in white) or dedicated to the right eye (represented in grey).

[0165] As with the horizontal subpixel version, viewpoints 1 to 5 are dedicated to the right image and viewpoints 6 to 10 to the left image.

[0166] 6.8. Embodiment 1=2 : P=6 : N=3 : M=3 : a=26.56° : horizontal sub-pixels

[0167] Figure 10 illustrates an embodiment of the invention representing a 6-viewpoint screen for displaying a 2-viewpoint autostereoscopic image. The pixel array is formed of horizontal sub-pixels and the optical grating has an inclination of 26.56° with respect to the vertical (in other words, 1=2; P=6; N=3; M=3; a=26.56°).

[0168] In this embodiment, each viewpoint addressed to each eye of the observer is framed by 2 buffer viewpoints on either side of that viewpoint.

[0169] 6.9. Embodiment 1=2 : P=10 : N=5 : M=5 : a=33.69° : sub-pixels ho rizontaux

[0170] Figure 11 illustrates an embodiment of the invention representing a 10-viewpoint screen for displaying a 2-viewpoint autostereoscopic image. The pixel array is formed of horizontal sub-pixels and the optical grating has an inclination of 33.69° with respect to the vertical (in other words, 1=2; P=10; N=5; M=5; a=33.69°).

[0171] Also, the only difference compared to the embodiment of [Fig.9] is the angle of the optical network, which implies a viewpoint filling grid adapted to this specific arrangement.

[0172] Of course, other configurations are possible than those shown, both in terms of the number of screen viewpoints and the tilt of the lenticular array.

[0173] Note that the embodiments of figures 9, 10 and 11 can be applied equally well to an IPS panel (English acronym for "In-Plane Switching"), to an organic light-emitting diode panel (better known by the English acronym OLED for "Organic Light-Emitting Diode") or to an active matrix organic light-emitting diode (better known by the English acronym AMOLED for "Active-Matrix Organic Light-Emitting Diode").

[0174] Indeed, like a screen whose pixels are composed of a plurality of sub-pixels of different colors superimposed on each other in the direction of the columns, anisotropic pixel panels can benefit from the invention to obtain a near-perfect resolving power, by preventing the optical axis of the lenses from intersecting contiguous pixels and generating ghost images.

[0175] 6.10. Embodiment 1=4: P=20: a=9.46°: vertical sub-pixels

[0176] Figure 12 illustrates another embodiment of the invention representing a 20-viewpoint screen for displaying a 4-viewpoint autostereoscopic image. The pixel array is formed of vertical sub-pixels and the optical grating has an inclination of 9.46° with respect to the vertical (in other words, 1=4; P=20; a=9.46°).

[0177] It differs essentially from the embodiment of [Fig. 6] because of the The number of image viewpoints is 4 here instead of 2, which implies a suitable viewpoint filling grid. The lens spacing is therefore twice as large.

[0178] In this figure as well as in [Fig.13], the 4 image viewpoints are represented respectively by white subpixels, grey subpixels, vertical hatched subpixels, and black subpixels.

[0179] In the embodiment of [Fig. 12], screen viewpoints 1 to 5 display the first image viewpoint (grey subpixels), screen viewpoints 6 to 10 display the second image viewpoint (hatched subpixels), screen viewpoints 11 to 15 display the third image viewpoint (black subpixels), and screen viewpoints 16 to 20 display the fourth image viewpoint (white subpixels).

[0180] The lens shown in the figure allows the stereoscopic pairs of viewpoints 3-8, 8-13, or 13-18 to be projected towards the observer, depending on their position. The viewpoints visible to the observer are separated from each other by four buffer viewpoints. Each viewpoint visible to the observer is framed by at least two screen viewpoints that display the same image viewpoint.

[0181] The number of screen viewpoints allows, despite the number of image viewpoints, for the maintenance of 2 buffer viewpoints on either side of each viewpoint addressed to the observer's eyes. In other words, each image viewpoint extends over 5 consecutive sub-pixels. As such, M=5 and N=5 can be considered for each of the image viewpoints.

[0182] 6.11. Embodiment 1=4 : P=20 : N=5 : M=5 : a=18.43° : vertical sub-pixels

[0183] Figure 13 illustrates another embodiment of the invention representing a screen at 20 viewpoints for displaying an autostereoscopic image at 4 viewpoints. The pixel array is formed of vertical sub-pixels and the optical grating has an inclination of 18.43° with respect to the vertical (in other words, 1=4; P=20; N=5; M=5; a=18.43°).

[0184] It differs essentially from the embodiment of [Fig. 2] due to the number of image viewpoints, which is here equal to 4 instead of 2, thus requiring a suitable viewpoint filling grid. The lens pitch is in this case twice as large.

[0185] Fig. 14 is a schematic view of a device for displaying a self-displaying image 2-point reoscopic according to an embodiment of the invention.

[0186] Such a device consists of a display screen 12 according to the invention, a display module 13 configured to display the right and left images according to the configuration described above, and a detection device 14 that, at each instant, detects the position of the observer's head 8 relative to the horizontal direction so as to allow the display module to slide the image viewpoints in each lobe in such a way that the said screen viewpoints visible to the observer are permanently framed by buffer viewpoints of the image viewpoint visible to that eye.

[0187] The tracking device 14 can be of any known type. It can be, for example, the device marketed under the reference Intel RealSense® SR300 (SDK1 Gold Release). This is an RGBD time-of-flight camera, accompanied by an optimized face-tracking library.

[0188] According to one variant, the detection device is configured to detect, at each instant, the position of the observer's head relative to a predetermined point on the display screen, allowing the X, Y, Z coordinates of the observer to be defined with a predetermined precision, in an orthonormal frame of which said predetermined point on the screen is the origin of said frame, the screen defining the X and Y axes of this frame and the direction perpendicular to the screen defining the Z axis of this frame.

[0189] As previously stated, this variant allows, in particular, the use of a screen according to the invention in an augmented reality application, for example, for simulation or head-up display applications in the automotive industry. Indeed, augmented reality requires high contrast. Black elements are transparent, while white elements are the most tangible. If one wishes to display a white square on a transparent background, it is essential to eliminate all possible causes of ghosting, which would interfere with the perceived images.

[0190] However, a device according to the invention which combines a screen according to the invention and a face tracking device makes it possible to obtain an almost perfect resolving power and therefore applicable to augmented reality applications.

[0191] The invention is not limited to the embodiments described. In particular, and as specified, different screens can be made to obtain an autostereoscopic device with near-perfect resolution. The invention revolutionizes the stereoscopic experience as we know it. The usual rules for composing stereoscopic scenes become obsolete, and all stereoscopic content can be displayed with unparalleled stereoscopic perception.

[0192] Although the vergence / accommodation dissociation persists, it becomes easier to get used to it, in the absence of any optical interference in the stereoscopic pair, of degradation of brightness and colours and without the bulk of 3D glasses or a headset.

[0193] Thanks to its unparalleled separating power and the exceptional amplitude of relief that it allows to be exploited, the screens of the invention make it possible to meet a very large number of demands for uses which are little or not met by existing devices.

[0194] The invention opens up countless market opportunities for individual autostereoscopic applications in a wide range of technical fields, among which include: medical imaging, surgical robotics, video conferencing, automotive, education, slot machines, remote monitoring, remote operation, drone piloting, aeronautics, mapping, seismology and geological, mining and petroleum prospecting, scientific studies at all scales, from the microscope to satellites, simulation, stereoscopic film production chain, CAD, design, mechanics, architecture, virtual tours, museums, games, telephony / tablets, entertainment, etc.

[0195] A particularly interesting application case of augmented reality concerns the particular application context where the background of the scene consists not of a physical set but of the display on a screen or by means of a projector of a 2D image, synchronized with the scene and representing the backgrounds.

[0196] The auto stereoscopic screen according to the invention allows for the display of an autostereoscopic image A very large-amplitude reoscopic effect, for example, 20 meters deep, occupies the entire physical space between the screen and the viewer, thanks to the invention of the 2D background image. Beyond about 20 meters, the eyes perceive little disparity, and monocular cues, such as perspective, become predominant. 2D backgrounds, if they incorporate strong visual cues like perspective, therefore perfectly complement the illusion and contribute to increasing the viewer's sense of immersion.

[0197] Such an installation is primarily single-user (especially when using a 2-viewpoint autostereoscopic image), but could nevertheless, due to the exceptional quality of filling of the two lobe sub-parts, be used by several users, positioned at the flat tint distance.

Claims

Demands

1. An autostereoscopic display screen with P viewpoints, referred to as screen viewpoints, P being an integer greater than or equal to 6, intended to display an autostereoscopic image with I viewpoints, referred to as image viewpoints, I being an integer greater than or equal to 2, less than or equal to P / 3, preferably equal to 2, said screen comprising: • a matrix (10) of pixels arranged by rows and columns, each pixel being composed of a plurality of sub-pixels of different colors, intended to display each one sub-pixel from one of the image viewpoints, • a cylindrical lenticular array or parallax barrier, called an optical array (11), configured to permit the projection of 1-1 pairs of predetermined screen viewpoints to the eyes of an observer located at a nominal distance from the screen, called the flat tint distance, said screen being characterized in that said optical array (11) is configured so that the P viewpoints of the screen can be perceived successively in a direction, called horizontal direction, by said observer at said flat tint distance, in spaces in front of the screen, called lobes, each covering I times the mean interpupillary distance of an observer (8), and so that the screen viewpoints of each pair of viewpoints visible to the observer at the flat tint distance are separated by at least T viewpoints, called buffer viewpoints, T being greater than or equal to 2, so that it is possible to display successively for each lobe, each of the I image viewpoints, repeated each P / I times, and that each viewpoint visible to the observer at the flat tint distance can be framed by at least 2 buffer viewpoints each displaying that same image viewpoint.

2. A display screen according to claim 1, characterized in that I is equal to 2 and in that said optical array (11) is configured to be able to display in each lobe, M times the image viewpoint dedicated to the left eye (L) of the observer and N times the image viewpoint dedicated to the right eye (R) of the observer, M and N each being greater than or equal to 3 and their sum being equal to P, and forming T buffer viewpoints between the viewpoint dedicated to the left eye and the viewpoint dedicated to the right eye.

3. Display screen according to claim 2, characterized in that M and N are odd such that each image viewpoint dedicated to each eye of the observer can be surrounded, in each lobe, by the same number of buffer viewpoints.

4. Display screen according to any one of claims 2 or 3, characterized in that M and N are equal such that the screen allows a symmetrical display of the viewpoints dedicated respectively to the left eye and the right eye of the observer.

5. Display screen according to any one of claims 2 to 4, characterized in that P is equal to 10 so that the screen presents 10 viewpoints and in that said optical array (11) is configured so that the pairs visible to the observer at the flat tint distance are the views 1-6, 2-7, 3-8, 4-9, 5-10 for viewpoints numbered successively from 1 to 10 so that each subpixel perceived by each eye of the observer can be surrounded on each side by 2 buffer viewpoints.

6. Display screen according to any one of claims 1 to 5, characterized in that said optical network (11) is formed of cylindrical lenses each having a principal axis which forms an angle α with the direction of the columns.

7. Display screen according to claim 6, characterized in that said angle a is between 0° and 45°, and preferably chosen from the group comprising the angles of 9.46°; 18.43°; 26.56°; and 33.69°.

8. Display screen according to any one of claims 1 to 7, characterized in that each pixel of said matrix (10) of pixels is composed of a plurality of horizontal sub-pixels of different colors superimposed on each other in the direction of the columns.

9. Display screen according to any one of claims 1 to 7, characterized in that each pixel of said matrix (10) of pixels is composed of a plurality of vertical sub-pixels of different colors juxtaposed to each other in the direction of the lines.

10. A device for displaying an autostereoscopic image with I viewpoints, referred to as image viewpoints, comprising: • a display screen (12) according to any one of claims 1 to 9, • a display module (13) configured to display, for each lobe, each of the I image viewpoints, repeated each P / I times, each viewpoint visible to the observer at the flat tint distance being framed by at least 2 buffer viewpoints each displaying that same image viewpoint.

11. Display device according to claim 10, characterized in that I is equal to 2 and in that said display module (13) is configured to display in each lobe formed by said display screen, M times the image viewpoint dedicated to the left eye of the observer and N times the image viewpoint dedicated to the right eye of the observer and forming T viewpoints, called buffer viewpoints, between the image viewpoint dedicated to the left eye and the image viewpoint dedicated to the right eye.

12. Display device according to claim 11, characterized in that it further comprises a detection device (14), at each instant, of the position of the observer's head with respect to said horizontal and / or vertical direction so as to allow said display module (13) to slide the image viewpoints in each lobe such that said screen viewpoints visible to the observer are permanently framed by buffer viewpoints of the image viewpoint visible to that eye.

13. Display device according to claim 12, characterized in that said detection device (14) is configured to detect, at each instant, the position of the observer's head (8) with respect to a predetermined point on the display screen, allowing the X, Y, Z coordinates of the observer to be defined with a predetermined accuracy, in an orthonormal frame of which said predetermined point on the screen is the origin of said frame, said screen defining the X and Y axes of this frame and the direction perpendicular to the screen defining the Z axis of this frame.

14. A method for displaying an autostereoscopic image at I viewpoints, I being an integer greater than or equal to 2, on a display screen at P viewpoints, called screen viewpoints, P being an integer greater than or equal to 6 and greater than or equal to 31, comprising a matrix (10) of pixels arranged by rows and columns, each pixel being composed of a plurality of subpixels of different colors, intended to display each one subpixel of one of the image viewpoints, and an array of cylindrical lenticles or a parallax barrier, called an optical array (11), configured to permit the projection of 1-1 pairs of predetermined screen viewpoints to the eyes of an observer located at a nominal distance from the screen, called the flat tint distance, and such that the P screen viewpoints can be perceived successively in a direction, called the horizontal direction, by said observer at said flat tint distance, in spaces in front of the screen, called lobes, each covering I times the mean interpupillary distance of an observer, characterized in that it comprises, for each lobe, the assignment to each adjacent screen viewpoint of each image viewpoint visible to the observer at the flat tint distance, of a copy of that image viewpoint such that, in each lobe, each of the I image viewpoints visible to the observer at the flat tint distance is framed by at least 2 buffer viewpoints each displaying that same image viewpoint,and in that it consists of a succession of I image viewpoints, each repeated P / I times.

15. A display method according to claim 14, characterized in that I is equal to 2 and in that it comprises, for each lobe: • the assignment to the first M screen viewpoints of the image viewpoint dedicated to the observer's left eye, • the assignment to the following N screen viewpoints of the image viewpoint dedicated to the observer's right eye, M and N each being greater than or equal to 3 and their sum being equal to P.

Images