FR2891063A1 - ELECTRONIC SCREEN WITH LENTICULAR NETWORK IN HONEYCOMB - Google Patents

Abstract

The general principle of the present invention consists in displaying the colored pixels of the electronic screens in honeycombs, which makes it possible to distribute them as homogeneously as possible and to obtain a good synthesis of the whites. This arrangement has been known since a long time, and applied in particular by some manufacturers of LED displays (LED stands for Light Emitting Diodes) .The originality is that here, it is not the light sources themselves that are arranged in triangles, but the lenses spherical lenticular network, and that it is the arrangement of these lenses relative to the RGB pixels that provides the desired result.

Description

Electronic lenticular honeycomb screen

  The present invention relates to a device associating an electronic screen 1 with colored light sources such as for example a liquid crystal screen, a plasma screen or a light emitting diode (LED) screen, with an optical lens assembly known by the term lenticular network, to allow the vision of still images or animated 3D without the need to wear specific glasses and / or the vision of still images or animated flat, with a better definition than that of the electronic screen 1 used.

  Optical devices known as lenticular arrays, which are often constituted by a plate of transparent material of which one face is plane and the other comprises a large number of cylindrical or spherical lenses 21, 22 and following, can be used to emit different images depending on the directions. They are used in particular for the production of relief images or for the restitution of animations.

  In these known systems, the image which is affixed on the electronic screen 1, opposite the lenticular network 2, is hereinafter called interlaced image because it comprises pixels (pixel comes from picture element and means an elementary part of image) that can come from several different images or from several subsets of a higher resolution image. These images are viewed successively by the viewer's garlic as it moves horizontally in a plane parallel to the interlaced image.

  The present invention has the advantage of allowing a very powerful, simple, rustic and inexpensive delivery of flat or embossed images.

  The proposed device is an optical device comprising: an electronic screen 1 comprising pixels, each of the pixels comprising sub-elements 11, 12 and 13 of different colors, hereinafter referred to as subpixels, a device called a lenticular network 2, comprising a plurality of optical devices said juxtaposed elementary devices, said elementary devices each comprising a convergent elementary lens or an equivalent optical system said elementary lens 21, said elementary lens 21 of the lenticular array 2 is a centered optical system 40 or assimilated, it being specified that the the term "centered optical system" is understood to mean either an optical system having an axis of symmetry of revolution substantially perpendicular to the focal plane of said elementary lens 21, or an optical system having substantially identical optical characteristics characterized by the fact that ' a projection of the optical centers of the elementary lenses 21, 22 and following on the plane of the electronic screen 1 is a set of points such that three of these points closest to each other are located each inside the surface sub-pixels of three different colors, the sub-pixels belonging to the same projection of the lenses being hereinafter referred to as active sub-pixels simultaneously.

  According to other characteristics of the invention: all the sub-pixels of the electronic screen 1 receive the projection of an elementary lens, and the projections of two closest elementary lenses 22 and 25 are located one in the upper half of the sub-pixel corresponding to it, and the other in the lower half of the sub-pixel corresponding to it; the face of the lenticular network 2 located on the side of the electronic screen 1 comprises prisms 72, 72 and following alternately deflecting the light upwards or downwards a column of sub-pixels out of two; The device simultaneously transmits several images called primary images in different directions, and the centers of two active subpixels 14 and 15 of the same horizontal line of subpixels are separated by an equal number of subpixels. to the number of so-called primary images, the active sub-pixel 16 closest to two active sub-pixels 14 and 15 in the line of sub-pixels immediately higher or lower is located as close as possible to the center of the segment joining said two active sub-pixels 14 and 15; it being specified that it is understood above by primary images as well as several original images that several extractions of pixels of the same image at higher resolution.

  the face of the lenticular network 2 located on the side of the electronic screen 1 comprises slots 41, 42, 43, 44 and following the right of the boundary between the sub-pixels located vis-à-vis; each of the active sub-pixels simultaneously represents a weighted average between: E on the one hand the value obtained by considering that the set of active sub-pixels simultaneously must represent the colored component of this color of the single image emitted, or of the image emitted in the direction considered for the case where several different images are emitted in different directions.

  On the other hand, the colored component of this color at the corresponding location of the single image emitted, or of the image emitted in the direction considered for the case where several different images are emitted in different directions, the lenticular network. 2 is constituted by the superposition of two lenticular networks 210 and 220 with cylindrical lenses, these two networks having a substantially common focal plane after being superimposed.

  the lenticular network 2 comprises means for periodically varying the relative positions of the lenticular array 2 and the electronic screen 1.

  The invention is a method of displaying one or more images according to an optical device according to the invention. The invention will be well understood, and other objects, advantages and characteristics thereof will appear more clearly on reading the following description, which is illustrated by Figures 1 to Figure 1, a distribution plane of the sub-pixels 11, 12 and following an interlaced image according to the invention in a configuration adapted to the display of a single image directed simultaneously to the two eyes of the viewer. The hexagons represent the elementary lenses 21, 22 and following of the lenticular network 2.

  Figure 2 is a perspective view of the lenticular array 2 of Figure 1.

  3, a perspective view, seen from the opposite side to the viewer, of a lenticular array 2 according to the invention in an improved embodiment where the lenticular network 2 consists of biconvex lenses, each of the elementary lenses comprising a second diopter noted 51.52 and following on the rear face of the lenticular network 2, which also has slots 61, 62 and following.

  4, a perspective view of the same face of a lenticular array 2 according to the invention, in another improved embodiment where the rear face of the lenticular array 2 comprises prisms 71, 72 and following, and slots 61 , 62 and following.

  5, a distribution plane of the sub-pixels 14, 15 and following of an interlaced image. The irregular hexagons represent the elementary lenses of the lenticular network 2 in a configuration adapted to the simultaneous display of two images each directed towards one of the eyes of the spectator.

  Figures 6a to 6d, the plane of distribution of the pixels of an interlaced image, in an embodiment of the invention in which the interlaced image combines sub-pixels from 4 different primary images. Each of these figures illustrates a different parallax allowing to see one of the 4 images.

  Figure 7, the pixel distribution plane of an interlaced image, in one embodiment of the invention wherein the interlaced image combines sub-pixels from 9 different primary images.

  8 to 10, three perspective views of the same lenticular network 2 provided with a slotted device 41, 42 and 43 preventing the viewer from seeing the partition walls of the sub-pixels of the electronic screen 1.

  FIG. 11: a variant of a device according to the invention in which the lenticular network 2 with centered optical systems is constituted by the assembly of two lenticular networks 210 and 220 with cylindrical lenses 2101, 2102 and following for the network 210 and 2201 , 2202 and following for the network 220.

  The general principle of the present invention is to display subpixels of different colors into triangles. This makes it possible to distribute them in the most homogeneous way possible and to obtain a good synthesis of the whites between the sub-pixels of different colors.

  This arrangement has been known for a long time, and applied in particular by some manufacturers of LED displays (LED stands for Light Emitting Diodes).

  The originality is that here, it is not the light sources themselves that are arranged in triangles, but the spherical elementary lenses 21, 22 and following of the lenticular network 2, and that it is the arrangement of these lenses with respect to RGB pixels that achieves the desired result.

  Several provisions are particularly advantageous: -Dispositions of type 1: Improvement of the definition in 2D This applies to all conventional screens not intended to display in 3D - Provisions of type 2: Improvement of the definition in 2D and in These arrangements are particularly interesting for small screens, such as those of phones, organizers and electronic games.

  - Type 3 arrangements: 3D distribution with 4 views These are the best performing layouts for an individual workstation - Type 4 provisions: 3D distribution to a higher number of views These provisions are dedicated to a large audience.

  Type 1 provisions: Improvement of the definition in 2D This applies to all conventional screens not intended to display in 3D The distribution plan is that described in Figure 1. The lenses are arranged in honeycombs almost perfect, and there are three for each RGB pixel, that is one for each sub-pixel.

  Figure 2 shows a perspective view of such a lenticular array.

  All the sub-pixels 11 of the electronic screen 1 here receive the projection of an elementary lens 21, and the projections of two elementary lenses 22 and 23 closest are located one in the upper half of the sub-pixel him corresponding, and the other in the lower half of the corresponding sub-pixel.

  Three immediately adjacent lenses form a triangle of three different colors, which allows an optimal white synthesis.

  The viewer actually perceives a pixel for each of these triangles. It thus perceives three times more pixels than with the original distribution.

  These first two figures show that there are twice as many rows of pixels in the lenticular network 2 as in the electronic screen 1, and that there are as many columns of pixels visible to the viewer as there are there were columns of subpixels in the electronic screen 1, but these columns of pixels are no longer really perceptible columns to the eye, and there are now three times more columns of pixels perceived than before .

  It is important in this type of arrangement that the lenses used are very short focal length, so that the viewer sees only the pixel provided with the lens located vis-à-vis.

  The shape of the lenses, shown in Figure 2, to facilitate understanding by a set of a spherical diopter and a planar diopter is not the best, the lenses used being advantageously biconvex.

  FIG. 3 shows such a lenticular network 2 with bi-convex lenses, which comprises a further improvement. This figure shows the rear face of this network, electronic screen side 1. It can see the convergent dioptres 51, 52 and following located at the rear of each elementary lens of the lenticular network 2, as well as slots 61, 62 and following practiced between these rear dioptres.

  The function of these slots 61, 62 and following is to ensure total reflection of the light rays from the sub-pixels of the electronic screen 1, and to prevent the eye of the viewer can see through an elementary lens a sub-pixel adjacent to the one facing the lens, even when the viewer moves significantly away from the optimal position in front of the screen.

  Another improvement is illustrated in Figure 4 which shows that the face of the lenticular array 2 located on the side of the electronic screen 1 comprises prisms alternately deflecting the light upwards or downwards a column of sub-pixels out of two. This corresponds to the fact that the projections of two horizontally adjacent elementary lenses are located one in the upper half of the corresponding sub-pixel, and the other in the lower half of the corresponding sub-pixel.

  The principle of the prism can obviously be combined with that of the rear diopter (not shown). Type 2 arrangements: Improvement of the definition in 2D and in 2D with 2 views These arrangements are particularly interesting for the small screens, like those of the telephones, organizers and electronic games.

  The plan of distribution is that described in Figure 5. The arrangement of the lenses is not a perfect honeycomb, but remains close to this ideal arrangement.

  Two horizontally adjacent sub-pixels 16 and 17 are seen by the two eyes of the viewer, one by the right eye and the other by the left eye.

  The focal length of the lenses F is ideally determined by the following formula F = D * i / y where D is the distance of the viewer, i is the distance between two horizontally adjacent sub-pixels, and y is the distance between the eyes of a average viewer (60 mm is a good value). This rule is also valid for all provisions of types 3 and 4 described below.

  It is important that the viewer is located at the intended distance, otherwise it would see with one of his eyes pixels that would not come from a single primary image. This is why this device is particularly suitable for products with small screens, because the viewer always keeps his phone, his organizer, or his electronic game at a distance that is known and fixed.

  This device can be used in two different ways: É For 3D, the primary images seen by each of the two eyes correspond to two different shots of the same scene, taken from two distant locations for example 6cm one of the other horizontally.

  For 2D, the primary images are two different extractions of the same image, which has the effect that each eye receives a different information that completes that received by the other millet. It is therefore possible to extract these primary images from a higher resolution original image than that of the electronic screen 1.

  It is not necessary in this arrangement, nor in any of the following, that a lens always corresponds to the same pixel. On the contrary, it is necessary that the displacement of the spectator is translated by a change of the pixel seen through a given lens, and the important point is that all these changes are simultaneous for all the elementary lenses of the lenticular network, at a sufficient modification. of the position of the spectator.

  Type 3 Provisions: 4-View 3D Diffusion These are the best performing layouts for an individual 50 workstation.

  The 4 figures 6a to 6d allow to see how the horizontal variation of the parallax allows the spectator to see successively the 4 primary images.

  In 3D, such an arrangement allows the diffusion of 3 stereoscopic pairs and an inverted pair, or 2 stereoscopic pairs and two monocular images if one of the 4 views is black.

  In this second case, there is no longer a risk of inverted stereoscopy, but half of the positions provide a feeling of relief even with the diffusion of 2D images.

  In the use in conventional 3D, with 4 different images, it is considered that a person manages quite easily to stall in three quarters of possible positions when this electronic screen 1 is that of his workstation.

  By changing the vertical orientation of the screen, which is very easy particularly with laptops, the viewer can also adjust the arrangement of images to see in any position the two central images. It is indeed one of the peculiarities of these devices that the vertical variation of the spectator results in a change of the primary images seen by the two eyes.

  Like the previous one, this device can also be used for the 2D with a very good resolution, since the 4 primary images are in this case 2 or 4 different extractions and thus complementary of the same original image, which can thus have a resolution significantly higher than the physical resolution of the screen.

  The fact of sending to both eyes information complementary to that received by the other millet allows the brain to recompose the original image which is higher definition.

  Type 4 Arrangements: 3D Diffusion to a Large Number of Views Figure 8 shows a 9-view layout. It is only an example of what can be achieved for display terminals intended for an audience likely to move in front of the screen.

  The principle is indeed compatible with practically all the possible numbers of primary images.

  The device displays simultaneously as many images called primary images in different directions, if desired, provided to respect the following rules: É the centers of two active subpixels 14 and 15 of the same line of sub -pixels are separated by a number of sub-pixels equal to the number of so-called primary images, É the active subpixel 16 closest to two active sub-pixels 14 and in the line of sub-pixels immediately higher or lower 40 is located as close as possible to the center of the segment joining said two active sub-pixels 14 and 15; Coding of the images displayed by the electronic screen 1 The viewer does not directly see the image displayed by the electronic screen 1, but a recomposition of all or part of the sub-pixels of this image, that which corresponds to the elementary lenses of the network lenticular that are aligned with his eye and one of these sub-pixels. There are two main methods for encoding these images.

  According to a first method, the set of active sub-pixels simultaneously represents the colored component of this color of the single image emitted, or of the image emitted in the direction considered for the case where several different images are emitted in different directions. ; According to a second method, each of the active sub-pixels simultaneously represents the colored component of this color in the corresponding location 55 of the emitted single image, or of the image emitted in the direction considered for the case where several different images are issued in different directions; The most advantageous method is to combine the two previous methods. Each of the simultaneously active sub-pixels then represents a weighted average between: on the one hand, the value obtained by considering that the set of active sub-pixels simultaneously must represent the colored component of this color of the single image transmitted, or of the image emitted in the direction considered for the case where several different images are emitted in different directions.

  on the other hand, the colored component of this color at the corresponding location of the single image emitted, or of the image emitted in the direction considered for the case where several different images are emitted in different directions.

  Elimination of dark bands The improvement described hereinafter and illustrated by FIGS. 8, 9 and 10 aims to eliminate the problem related to the dark bands that most screen manufacturers have between the sub-pixels.

  It consists in that the face of the lenticular network 2 located on the side of the electronic screen 1 comprises slots 41, 42 and 43 in line with the boundary between the sub-pixels situated opposite each other; Even if they have a similar function which is to provoke a total reflection, these slots are not exactly the same as those described in FIGS. 3 and 4 which did not lie at the border of the sub-pixels situated in the opposite direction. to face. They are therefore denoted by different reference numbers.

  In other words, an additional optical structure is added to the rear face of the lenticular array 2, or else to a structure separate from the lenticular array 2.

  Each small rectangular structure surrounded by slots corresponds to a sub-pixel of the electronic screen 1, and the 4 lateral faces of each of said small rectangular structures have a slight relief which has the consequence that the rays coming from the sub-pixels are think totally.

  In FIG. 10, the plane L is that of the optical centers of the elementary lenses; The plane F is that of the departure of the slots 41, 42 and following; É and the plane C is that of the rear faces.

  If it is not possible to bring the plane C close enough to these rear faces of the plane of the sub-pixels, each rear face may advantageously, instead of being plane, be a convergent spherical lens (not shown in these figures). .

  Advantageously, an elementary lens 21 of the lenticular array 2 45 focuses on the plane F said starting slots 441, 42 and 43.

  Another way to solve the problem of dark strips is to minimize their surface by having reflective surfaces that meet between two light sources. This is a particularly recommended solution for LED screens: each LED receives a spherical or parabolic reflector which is advantageously frosted, and these reflectors are perfectly joined to each other so that there is no dark area between two sources bright.

  Devices with variable geometry Some light sources used in the construction of electronic screens, such as LEDs, can be switched on and off at a very high rate, with little or no remanence.

  Some manufacturers of LED screens use this physical feature to achieve several successive displays of images that are different extractions of pixels from the same higher resolution image than that displayed at a time t by the electronic screen 1, this which improves the sharpness of the image perceived by the viewer.

  However, it must be considered that retinal persistence causes the human eye to confuse these successive displays.

  It is different when the geometry of the device has been changed between two successive displays, because the human eye then perceives two successive displays at two different locations.

  The resolution of a device according to the invention can be considerably improved organizing a periodic movement which may concern any one of the two constituents that are the electronic screen 1 and / or the lenticular network 2.

  The means used to periodically vary the relative positions of the lenticular array 2 and the electronic screen 1 may be either mechanical means or magnetic means such as one or more electromagnets vibrating the lenticular array 2 in its plane, or electronic screen 1 in his plan.

  It is also possible to use all kinds of movements according to the number of successive ignitions provided during a complete periodic movement: for example linear reciprocating or circular, or a combination of such movements. A horizontal back and forth motion is particularly recommended to increase the number of primary images.

  General Considerations In the present description and in the claims that follow, the term lenticular array 2 is used to describe sets of lenses of different types. It goes without saying that this expression must be understood in the broad sense, and that lenticular networks with optical systems centered, with double cylindrical or annular lenses can be replaced by opaque plates having holes or circular transparent zones, or whimsical shapes in place and place of optical systems described.

  Similarly, the electronic screen 1 is ideally a liquid crystal display or a plasma screen or a screen with colored light sources such as light emitting diodes (LEDs), but the device also works with any printed image whose pixels comprise subpixels of different colors.

  In all the foregoing descriptions, the lenticular arrays are shown with the spectator-side lenses, but the converse is possible and has the advantage in some cases of allowing optical centers to be brought closer to the lenses of the sub-pixel plane, without as much to have to decrease the thickness of the piece of plastic.

  All the above descriptions represent implementations of the patented device with electronic screens whose sub-pixels are 3 rectangles juxtaposed to form a square, but the invention can also be implemented with any other original arrangement of the sub-pixels, and in particular with LED screens whose LEDs are themselves arranged in triangles.

  Certain provisions are not compatible with the display of images not encoded by the electronic screen 1. A solution for still being able to display such uncoded images is to bring the lenticular network 2 closer to the electronic screen 1 so that that its elementary lenses no longer focus on the plane of the electronic screen 1 and deviate almost no longer light rays. Such displacement of the lenticular network 2 relative to the electronic screen 1 can be caused manually, or preferably by an electromagnetic or pneumatic device for example.

  Small screens are advantageously produced by injection. A monobloc piece can then also fulfill other functions (pivoting, sliding, bringing the lens plane closer to that of the sub-pixels to suppress the effect of the lenses).

  The large screens are produced by pouring into a mold (a process already used for producing the screens of back-projectors), or by juxtaposition on a glass plate of slabs produced by injection, or by other printing processes of lenses by screen printing or stereo-lithography, or other known methods.

  It is also possible to make large screens by superposition of two cylindrical lenticular lens networks as illustrated in FIG. 11. The lenticular network 2 is then constituted by the superposition of two lenticular networks 210 and 220 with cylindrical lenses, the elementary lenses of these lenses. two networks having a substantially common focal plane after being superimposed.

  Applications The main applications of the present invention are: advertising display, advertising signs, promotion at the point of sale, the composition of virtual showcases; all applications of television, video and film, and in particular the following: sports broadcasts, films and serials, television news and reports, video games, advertising, amusement park attractions, computer-aided design workstation terminals, product design and architecture, scientific visualization, medical imaging (3D X-rays, NMR, CT, ultrasound, endoscopy, microsurgery, etc.); piloting equipment and flight simulators, personal films, education, mission planning, reconnaissance, damage assessment, terrain analysis, cartography, geography, seismic research , teleconferencing, mobile phones, organizers; luminaries, works of art, decorative objects and gadgets.

Claims (9)

claims   An optical device comprising: an electronic screen 1 comprising pixels, each of the pixels comprising sub-elements 11, 12 and 13 of different colors, hereinafter referred to as sub-pixels, o a device called a lenticular network 2, comprising a plurality of pixels; optical devices called elementary devices juxtaposed, said elementary devices each comprising a convergent elementary lens or an equivalent optical system said elementary lens 21, said elementary lens 21 of the lenticular array 2 is a centered optical system or the like, it being specified that we mean by optical system centered or similar: E also an optical system having an axis of symmetry of revolution substantially perpendicular to the focal plane of said elementary lens, É an optical system having substantially identical optical characteristics characterized by the fact that a projection optiq centers ues elementary lenses on the plane of the electronic screen 1 is a set of points such that three of these points closest to each other are located each inside the surface of sub-pixels of three different colors, the sub-pixels belonging to the same projection of the lenses being hereinafter referred to as active sub-pixels simultaneously.   2. An optical device according to claim 1 characterized in that all the sub-pixels of the electronic screen 1 receive the projection of an elementary lens 21, and the projections of two elementary lenses 21 and 22 closest are located one in the high half of the sub-pixel corresponding to it, and the other in the lower half of the sub-pixel corresponding to it.   3. An optical device according to claim 2 characterized in that the face of the lenticular array 2 located on the side of the electronic screen 1 comprises prisms 71, 72 and following alternately deflecting the light upwards or downwards a column of sub pixels on two.   4. The optical device as claimed in claim 1, simultaneously emitting several images called primary images in different directions, characterized in that: the centers of two active subpixels 14 and 15 of the same horizontal line of subpixels are separated from each other. a number of sub-pixels equal to the number of so-called primary images, where the active sub-pixel 16 closest to two active sub-pixels 14 and 15 in the line of sub-pixels immediately higher or lower is located nearest possible from the center of the segment joining said two active subpixels 14 and 15 being specified that it is understood above by primary images as well as several original images that several extractions of pixels of the same image at higher resolution.   5. An optical device according to claim 1 characterized in that the face of the lenticular array 2 located on the side of the electronic screen 1 comprises slots 41, 42, 43, 44 and following to the right of the boundary between the sub-pixels. located vis-à-vis.   6. An optical device according to claim 4, characterized in that each of the active sub-pixels simultaneously represents a weighted average between: E on the one hand the value obtained by considering that the set of active sub-pixels simultaneously must represent the component colored of this color of the single image emitted, or of the image emitted in the direction considered for the case where several different images are emitted in different directions, and on the other hand the colored component of this color at the location corresponding of the single image emitted, or of the image emitted in the direction considered for the case where several different images are emitted in different directions.   7. An optical device according to claim 1 characterized in that the lenticular network 2 is constituted by the superposition of two lenticular networks 210 and 220 cylindrical lenses, these two networks having a substantially common focal plane after being superimposed.   8. An optical device according to claim 1 characterized in that it comprises means for periodically varying the relative positions of the lenticular array 2 and the electronic screen 1.   A method of displaying one or more images according to an optical device according to any one of the preceding claims.