WO2022074409A1

WO2022074409A1 - Method and device for displaying a 3d image

Info

Publication number: WO2022074409A1
Application number: PCT/HU2021/050054
Authority: WO
Inventors: Robert VON SCHLEINITZ
Original assignee: Von Schleinitz Robert
Priority date: 2020-10-06
Filing date: 2021-09-30
Publication date: 2022-04-14
Also published as: HUP2000327A1

Abstract

The invention relates to a method for displaying a 3D image in which media contents consisting of two half-frames are displayed on a flat display screen. The display screen (1) consists of pixels (3) arranged in a matrix grid (6). In the method a matrix grid made of a material permeable for the light and consisting of micro-lenses is placed on the display surface (2) of the display screen (1). Certain pixels of the first half-frame are transmitted to the corresponding first pixels (14) and certain pixels of the second half-frame are transmitted to the corresponding second pixels (15) at the same time by means of a control electronics. The invention further relates to a device for displaying a 3D image for implementing the method. The micro-lenses (8) are wedge-shaped elements formed as microprisms (7) bordered by flat surfaces or the micro-lenses (8) are convex lenses formed of a base plate (9), a convex cover plate (12), and optionally a convex side plate (13). The pixels (3) forming the rows (4) of the matrix grid (6) are arranged in pixel pairs (16) in such a way that one micro-lens (8) shaped as a first microprism (17) is placed on the surface of the first pixel (14) and a second micro-lens (8) shaped as a second microprism (18) is placed on the surface of the second pixel (15), or a micro-lens (8) in the form of a convex lens or a cylindrical asymmetric convex micro-lens is placed on the pixel pairs (16). One half-frame is transmitted to the first pixels (14), the other half-frame is transmitted to the second pixels (15) simultaneously by means of the control electronics.

Description

METHOD AND DEVICE FOR DISPLAYING A 3D IMAGE The present invention relates to a method for displaying a 3D image. Without an external aid, 3D display of media contents consisting of two image parts – hereinafter called two half-frames: first half-frame and second half-frame – on a flat display screen is performed for the viewer(s). The display is performed on the display surface of the display screen consisting of light points (hereinafter: pixels) formed from elementary RGB light sources. The display screen consists of pixels arranged in a matrix grid of rows and columns. In the method a matrix grid preferably formed on a single sheet substrate is placed on the display surface i.e. on the viewer(s) side of the monitor, the substrate is made of a water-clear material permeable for the light beam and consisting of micro-lenses – including microprisms – adjusted to the size of the pixels. The transmission of the given points of the half-frames to the corresponding pixels is performed by control electronics. The invention further relates to a device for displaying a 3D image, implementing the method described above. The device is suitable without an external aid for 3D display of media contents consisting of two image parts – hereinafter called two half-frames – on a flat monitor display for the viewer(s). The display surface of the display screen consists of light points (hereinafter: pixels) formed form elementary RGB light sources. The pixels are arranged in a matrix grid of rows and columns. A matrix grid formed on a single sheet substrate is placed on the display surface of the display screen, preferably, the substrate is made of a water-clear material permeable for the light beam and consists of micro-lenses having a triangular cross-section – including microprisms – adjusted to the size of the pixels. The given points of the half-frames are transmitted to the corresponding pixels by control electronics. Several solutions have already been developed for the display of 3D images. The main issue in visualizing a 3D image is that the necessary image should be conveyed to each eye, so most of these solutions used some kind of aid. One common feature of these is that some external aid, such as glasses, was required to display the 3D image. According to the current state of art, a stereoscopic 3D image experience that can be perceived by the naked eye can be made possible by the application of two completely different technical possibilities. One is the Lippmann integral lens, which has been used since the late 1920s, and referred to as lenticular lenses since the 1930s in the French, German, and English science. The other solution is the “parallax barrel”, the very first public presentation of which is named after the French painter G. A. Bois-Clair from 1692. Centuries later, in 1903, the same technique was used in his photographs by the American photographer Frederick E. Ives. A few years later, in 1906, in France, the procedure was already referred to as a “parallax stereogram”. The solution of the present invention is practically an advantageous combination of the two technical solutions in so far as the physical design of the device realizes the design typical of lenticular lenses, which is advantageous for industrial implementation and later for series production. In addition, in the control of 3D content, practically the “image masking” technique of the parallax barrel is mapped in a virtual way. The advantage of the used lenses over the planar prisms is that they emit the light of a given pixel at a greater angular opening to the eye with precise control. This makes the display more tolerant of smaller movements and a much more intense 3D image experience is presented for the user. The method of the present invention realizes all the advantages of the two applied techniques at the same time. In addition, it seems feasible that in the future with the help of engineering precision-controlled light beams, not only the 3D effect can be viewed in a passive manner from one point of the space, but by using an active control a 3D display viewed from several viewpoints also can be created. Presumably, this will be possible with the use of a combined lens system designed for multiple focal points. In the current state of the art of 3D stereoscope technology, auto-stereo techniques using parallel barriers are known. The main feature of auto-stereo displays is that they are able to create a sense of spatiality without the use of special aids such as glasses. Here, too, the well- known basic idea is applied, namely, different images are provided to the right and left eyes. This is accomplished by placing various optical devices and elements directly in front of the screen carrying the image information. The viewer's comfort and the usability are significantly limited by the devices needed to evoke the effect of spatiality, such as glasses. Attempts are made to overcome this shortcoming by means of so-called autostereoscopic displays, where the separation realized by the spectacles is provided by other means placed close to the screen. The two best-known versions of the displays are the lenticular and parallax stereo displays. The lenticular version is also referred to as a micro-lens system because an optical unit composed of micro-lenses of the same focal length is located in front of a pixel-controlled electronic display. If we look at the display through this optical system, different pixels become visible to the right and left eyes, so two different images are created, which, when they reach the brain, create a stereo effect. The disadvantage of this method is that it is sensitive to the position and the viewing distance. Another known version is the parallax stereo display, which includes a grid structure in front of the electronically controlled screen. The design of the grid structure is such that it makes different screen pixels visible to the eyeballs at different points in the space. The task of the screen controller is to assign different images to the pixels separated by the grid structure, thus ensuring the spatiality. It should be emphasized that both methods are sensitive to the viewing distance and the position. In case of incorrect viewing distance or position, due to the overlap of the related image parts, the inverted - pseudoscopic - image is displayed instead of the correct - orthoscopic - image, which makes the image blurry. According to one of the known solutions the image sent to the two eyes was separated based on color. In this case, complementary colors were used: red-green, red-blue. In this case, the images appeared on the projector at the same time and the color filter glasses separated them by color. Spatial image display thus operated with color segmented separation, each eye received an image separated by a color filter, resulting in a spatial image assembled in the brain. A partial disadvantage of this was that the colors obtained in the spatial image were not completely perfect. In an alternative solution polarized separation was used. For display, the polarization of the light for the two eyes was alternated at 90°, and a filter with the appropriate polarization was placed in front of the two eyes, in this way each eye received only the image sent to it. This created a spatial effect, a spatial experience, and the colors were also perfect. The disadvantage of this was that the polarized separation required controlled intelligent polarization glasses to be placed on the head in front of the eye, which transmitted the currently displayed image to one eye or the other. This was alternated very many times per second, at a speed of 100-120 Hz, so the images obtained gave the viewer a continuous spatial experience. The inconvenience of the solution was caused by the fact that a relatively large device had to be used on the head, and experience showed that after a while the observer's head began to ache. According to previous solutions, the so-called SBS-Side by Side systems are also known. Another 3D display technique is the so-called "parallex barrel". In doing so, gap was vibrated before the eye and this created a spatial image. In this case glasses were also needed. The disadvantage of the spatial display methods known so far is that a separate device was always needed to display the 3D image, because the image visible to the right and left eyes had to be filtered. With regard to spatial imaging and image reproduction, taking into account the relevant technical literature and experience, it can be concluded that a horizontal representation of the elements of the image is sufficient to create a spatial image experience. Chinese patent application CN107065206 discloses an autostereoscopic display having a layer ensuring backlight and image display and an LCD prism layer interposed between two layers containing control electrodes. Patent application US 20150138184 discloses a mobile device display design which, due to its structural design and software control, is suitable for displaying two and three-dimensional visual content with or without 3D glasses. The mobile device is further provided with a unit which continuously evaluates the distance and orientation of the user's face and eyes from the mobile device to maintain and possibly correct the 3D sense of space. Patent application US 20150316776 discloses a specification and device for displaying autostereoscopic image content with a microprism system and an LCD panel (operating on the principle of parallax barrier) positioned before it. Three-dimensional display technologies Jason Geng Advances in Optics and Photonics Vol.5, p.456-535 (2013). Received May 28, 2013; revised September 17, 2013; accepted September 30, 2013; published November 22, 2013 (Doc. ID 188297) provides a complete overview of three-dimensional displays and imaging technologies, including autostereoscopic techniques. This document is a completely general approach to experiences visible without the use of 3D devices to the naked eye. In this study, a general mention is made of display systems operating with this technology. It gives a detailed, comprehensive knowledge of holographic technology, which virtually shows no relevance to our development which is based on the improvement of autostereoscopic display systems. No special technology not known until the publication of the study is mentioned in the document. Figure 25 of the study describes the methodology of a 360-degree hologram display based on LED technology. The basic essence of this modeling is the so-called parallax barrier, which in this form has no technical relevance that would be related to the solution according to the present invention. We also use this parallax barrier effect, however, not in the physical design of the device, but it is modelled by our control software for our 3D display. The aim of the study is to summarize the technical solutions that already exist, i.e. at the time of writing this article, in 2013 and to weight them, giving them priority, which ones are worth developing in the future, which ones are promising in which areas. The study does not discuss any real solutions for industrial applicability, these are purely theoretical approaches as opposed to the solution of the present invention - as an industrial feasibility based on significant mathematical calculations is also disclosed in the present application. In Figure 26, the study discusses the use of a so-called lenticular lens dating back to 1916, the basic essence of which is to collect different points of light at different focal points. Point 3.4.b of the same article points to a number of applicable solutions using lenticular lenses. The study mentions several times that there are still many opportunities to improve these alternatives. The solution described in Fig.27, i.e. the lenticular solution, has nothing to do with the solution according to the present invention. Figure 3.4c offers a solution, the essence of which is that multiple viewers can enjoy the 3D effect at the same time. The obvious disadvantage of this solution is that it provides only a very small, and sometimes no angular tolerance for the viewer (s), so a small movement - the movement of the viewer or the device - can also mean the interruption or loss of the 3D experience. To eliminate this - and given that the solution of the present invention is not developed for a large display, but for a small size, 5-6-10 inches - we provided the user with a 3D experience in the most sophisticated and accurate way. In our case, the change of image angles, the user's eye movement, the movement of the display in any direction, more than 14 degrees is tolerated by our system and the 3D depth experience is uninterrupted in Full HD, 2K or 4K quality. Point 3.4d of the article is the presentation of a 3D projector, which is practically unrelated to the present development, as the image content is not radiated directly to the right and left eyes, but it works with different light scattering and light intersection points. This system is also designed to provide a multi-user, multi-viewer experience as opposed to ours. Point 3.10b discusses the 2D and 3D function already described by Sony in 2013, the essence of which, more precisely, its technical essence is, that the aforementioned parallax barrier effect is intended to be realized in the least possible physical form, which differs significantly from the present development as this essential effect is modelled with software and this effect is forced on 3D content through a video controller, not through physical design. Figure 48 analyzes a special four-user large display system, obviously with the same drawbacks already mentioned. Here, the 3D effect provides a sensitive, unstable 3D experience, as opposed to our 3D system. This multi-view effect also occurs in the technical solution we have developed, but we only treat this as a side effect due to the nature of light and do not use this side effect. Article 4 and its subchapters discuss the future development and application of a very costly and complex 3D solution. This solution works by coordinating pixel-guided and directed laser beam projections, but the article does not cover industrial applicability or imaging quality. This would require a great deal of research. Laser-operated devices are the most expensive on the market to this day. Our goal was to provide the most effective 3D experience in such a way that the industrial feasibility of our devices and their series production would not differ significantly from the production cost of a traditional display. At https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-27-24-35728&id=423365, titled Time- multiplexed light field display with 120-degree wide viewing angle, published by Boyang Liu, Xinzhu Sang, Xunbo Yu, Xin Gao, Li Liu, Chao Gao, Peiren Wang... - Bejing University of Posts and Telecommunications, and a technical monograph published in Optics Express Vol. 27, Issue 24, p.35728-35739 (2019), provides an overview of three-dimensional displays and visual display technologies. The authors have published a 3D feasibility study on how a holographic and a semi- holographic effect can be achieved using already known autostereoscopic solutions. These autostereoscopic solutions are the lenticular lenses and parallax barrier solutions mentioned in previous studies, as well as their combined solution. The essence of the holographic solution is that by circling the projected content up to 360 or 180 degrees, a different profile and side of the 3D object and content can be seen from each angle - with which the effect that the object really comes to life is created and we can walk around it. In contrast, the autostereoscopic solution is based on interlacing 2 absolutely flat 2D images that take advantage of the natural 3D imaging of the brain. This study analyzes a solution where the viewer experiences a holographic effect that can be walked round at 120 degrees through an auto-stereoscope system, so it has no common features or technical connection with the device of the present invention, in which no holography is used at all. In addition, the figures belonging to this system show that they refer to their own 3D content recorded with a complex camera system with 12 cameras, which also has nothing to do with the device proposed in the present invention and cannot be linked to our goals. The device according to the invention is developed to be compatible with all 3D content existing on the market and the video controller is developed also in this way. These documents describe solutions which differ from the present invention in their essential elements. The solutions according to the invention are not known from the prior art documentation. Nor can a person skilled in the art be expected to realize the present invention from a combination of previously known documents. Hungarian patent application P1700520 describes a method and a device for displaying a three-dimensional image without spectacles. In the method proposed there, the stereoscopically recorded color image is displayed horizontally left-to-right, at a given display segment pixel spacing, alternating in time, and is alternately projected by means of controlled prisms consisting of LCD elements placed in front of the display segment pixels for the left eye and right eye. In doing so, until e.g. the image to be sent to the left eye is displayed on one of the display segment pixels, the controlled prism projects it to the left eye, and does not show it to the other, e.g. the right eye. In the case of the other, e.g. the right eye, this process may take place laterally away from some of the display segments, and the controlled prism at that location, advantageously an LCD device, projects this image to the right eye. Thus, by alternating left and right laterally at a sufficient speed and satisfactorily controlling the display prisms, a 3D image is created for the viewer while viewing the screen of a flat display device. In the display screen of the device, controlled prisms arranged in horizontal rows and vertical columns as elementary light pixels are placed in front of the RGB lighting segments forming the elementary light pixels. These project the pixel light of a given elementary segment horizontally to the right or left, depending on the control. The object of the above-described invention was to provide a method and a device which separates the two images to be displayed to the left and right eyes already in the display unit without external aids, and by suitably displaying the images to the left and right eyes the 3D image is assembled for the viewer. In the description of the invention described in Hungarian Patent No. P1700520, the lack of teaching is such that a person skilled in the art is not able to achieve the object defined in the invention. The invention described there is not applicable industrially on the basis of the information currently available, since it does not contain any information about the material of which the controlled prisms are made and about the material which fills the space between the LCD prism surfaces and the pixels. This is essential for optical density and ultimately through optical density for the functionality of the invention. This is because, depending on whether the material of the prism is optically sparser or denser than its surroundings, the light beams emerging from the subpixels and passing through the prism and finally emerging from it may be diverging or converging. From the point of view of industrial applicability, it is questionable whether the display is suitable for the intended purpose, since the angles of the microprisms placed in front of it result in a flat triangle in which a significant part of the subpixels R, G, B is completely hidden from the viewer by the alternately controlled LCD prism surface. As a result, the image content on the screen will not be color-correct and the sense of space will not be created. According to the invention described in Hungarian Patent No. P1700520, 1 LED per pixel is used with active electronic control by alternately directing the light rays at appropriate angles to the right and left eyes. This is achieved by placing two prismatic LCD (liquid crystal) prisms of equal rectangular cross-section in front of the light emitting LED. This is done in such a way that the prisms lie in front of the LEDs with their rectangular base defined by their horizontal legs. They are joined together by their rectangular side panels defined by their vertical legs. The light beam is directed alternately (60 flashes/sec voltage) to the right and left eyes, respectively. The images on the right and left side are transmitted alternately to the right and left eyes by flashing every 60 seconds. Practically, the light of the same LED is transmitted alternately to the right and left eye. The control software electronically shuts off the path of the light beams alternately to the left and right eyes through the prisms. This solution has several disadvantages over the solution according to the present invention. Its electronic feasibility is complicated. Due to the continuous overload of the image controlling processors, the overall system control slows down or breaks. Its physical feasibility is costly due to the extra costs involved in series production. As a result, the economic success of the product is questionable. According to the present invention, two adjacent pixels of RGB LEDs are controlled at the same time and the light beams they emit simultaneously are directed at the appropriate angle to the right and left eyes. The images of the right and left sides are displayed simultaneously, preferably at 60 flashes per second, so that every second vertical column of the digital pixel array corresponding to the respective sides is projected into the respective successive prisms having continuous light transmission capabilities. In this case, the control software splits the 3D digital content into vertical bands and transmits it to the appropriate prism column. The geometry of the prisms can be calculated by a mathematical equation explained later in the description, which can be easily programmed in this way. Another feature of the prisms is the individual refractive index of the light-transmitting material used. Together, the angle of the prisms and the associated physical refractive index provide a passive technical solution by which the right and left half-frames can be transmitted to the appropriate eye. The 3D display according to the solution of the present invention allows the use of significantly fewer electronic components. By using shorter control algorithms, processors will have much more free capacity making 3D image control faster, smoother and more accurate. (This is especially true for playing 3D contents requiring more memory.) Due to the more cost-effective physical feasibility, the consumer price of mass-produced end products can be significantly reduced. The object of the solution according to the invention was to provide a method and a device which is simpler, cheaper and actually feasible than the solution described in Hungarian Patent No. P1700520. It is not necessary to alternately close the light transmission of the prism surface facing the left or right eye. For this reason, the use of a light-blocking element which is complicated to control and which is unnecessary in the solution according to the present invention can be omitted. The use of electronic control of the light-blocking element may be omitted. Of course, it is also an object of the present invention to separate the two images to be displayed to the left and right eyes already in the display unit without external aids. Furthermore, the half-frames thus produced are transmitted to the left and right eyes separately, as a result of which the viewer will see the corresponding spatial image. The aim is to convert a display with traditional LED pixels into a special monitor using a combination of the appropriate hardware and software, which does not require the use of any external devices (e.g. 3D glasses or VR head set) used to display 3D contents (which can be still or moving images). The only role of these external devices was to transmit the signals of the right and left image channels separately from each other in a passive or active way to the corresponding eye. It has been realized that when a specially formed electronically controlled LCD prism system is placed in front of a commonly used high-resolution, optionally large, LED display screen, and the image displayed by the LED display screen is represented horizontally at high speed in rotation, separately at a time for the two eyes the viewer will perceive a 3D image. The present invention is a method for displaying a 3D image. Without an external aid, the 3D display of media contents consisting of two image parts, hereinafter two half-frames, first half- frame and second half-frame, is performed for the viewer(s) on a flat display screen. The display is performed on the display surface of a display screen consisting of light points (hereinafter: pixels) formed of elementary RGB light sources. The display screen consists of pixels arranged in a matrix grid of rows and columns. In the method, a matrix grid preferably formed on a single sheet substrate is placed on the display surface i.e. on the viewer(s) side of the display screen, the substrate is made of a water-clear material permeable for the light beam and consisting of micro-lenses – including microprisms – adjusted to the size of the pixels. The transmission of the given points of the half-frames to the corresponding pixels is performed by control electronics. In the matrix grid, micro-lenses of a base plate size substantially equal to the size of one or two pixels are used. The pixels are arranged in pixel pairs consisting of a first pixel and a second pixel. A common micro-lens or a micro-lens designed separately for the first pixel and the second pixel per pixel is placed on the pixel pairs in the display surface of the display screen. The micro-lenses are designed so that the light beam emitted by the pixels is projected toward the centerline of the display screen in such a manner that the light beam emitted by each first pixel is projected into one eye of the viewer(s) and the light beam emitted by each second pixel is projected into the other eye of the viewer(s). This is done by controlling the given pixels of the first half-frame to the corresponding first pixels and the given pixels of the second half-frame to the corresponding second pixels at the same time. The invention further provides a device for displaying a 3D image, for carrying out the method described above. The device is suitable to display without an external aid, the 3D display of media contents substantially consisting of two image parts, hereinafter two half-frames, first half-frame and second half-frame on a flat display screen for the viewer (s) The display surface of the display screen consists of light points (hereinafter: pixels) formed from elementary RGB light sources. The pixels are arranged in a matrix grid of rows and columns. A matrix grid is placed on the display surface of the display screen, preferably, the grid is made of a water- clear material permeable for the light beam and consisting of micro-lenses with triangular cross-section – including microprisms – adjusted to the size of the pixels. The given points of the half-frames are transmitted to the corresponding pixels by control electronics. The micro- lenses having right-angled triangular cross-sections are wedge-shaped elements bordered by flat surfaces consisting of a base plate, a side plate and a cover plate and are formed as a microprism. The micro-lenses are convex lenses formed of a base plate, a convex cover plate, and optionally a convex side plate. The size of the base plate substantially equals to the size of one or two adjacent pixels. The pixels forming the rows of the matrix grid are arranged in pixel pairs consisting of a first pixel and a second pixel, in such a way that one microprism- shaped micro-lens is placed on the surface of each first pixel on the viewer-side and another microprism shaped micro-lens is placed on the surface of each second pixel on the viewer side, or a micro-lens in the form of a convex lens is placed on the pixel pairs in such a way that the base plate of the micro-lenses lie on the viewer side surface of the pixels placed in the display surface of the display screen. The light beam emitted by the pixels are directed towards the center line of the display screen in such a way that the maximum height of the cover plate or the convex cover plate of the micro-lenses measured from the base plate is at most at the center of the micro-lenses or it is formed from the center of the micro-lenses to the center line of the display screen, further, the first half-frame is transmitted to the first pixels, the second half-frame is transmitted to the second pixels simultaneously by means of the control electronics. Preferred embodiments of the invention will be described in the appended claims. Detailed description of the method and the device according to the invention will be given with reference to the accompanying drawings. In the Figures only a portion of the display screen according to the invention is shown, considering that the number of the rows and columns of the display screen are significantly more. Figure 1 schematically shows the arrangement of the rows and columns in a matrix grid; Figure 2 schematically shows the display screen in which two pixels under each other in the columns, i.e. a first pixel and a second pixel are arranged in a pixel pair; Figure 3 schematically shows an arrangement of the microprism shaped micro-lenses; Figure 4 schematically shows an arrangement of the convex lens-shaped micro-lenses; Figure 5 schematically shows a display screen design in which two adjacent pixels in the rows, i.e. a first pixel and a second pixel are arranged in a pixel pair; Figure 6 schematically shows a display screen in which the first pixel and the second pixel are arranged like a chessboard; Figure 7 schematically shows the arrangement of the microprism-shaped micro-lenses where the microprisms within the eye distance overlap the pixel pairs with their side plates facing each other using the columnar representation of Figure 5; Figure 8 shows the arrangement of the convex lens-shaped micro-lenses in which the micro- lenses within the eye distance are symmetrical, while the micro-lenses out of the eye distance are asymmetrical, so called cylindrical in shape, and the columnar representation of Figure 5 is used; Figure 9 schematically shows the light beams emitted from the microprism-shaped micro- lenses arranged in one of the rows as shown in Figure 2, where the microprisms within the eye distance overlap the pixel pairs with their side plates facing each other, and the row emits the light beams to one eye; Figure 10 schematically shows the light beams emitted from the microprism-shaped micro- lenses arranged in the row adjacent to the row shown in Figure 9, where the microprisms within the eye distance overlap the pixel pairs with their side plates facing each other, and the row emits the light beams to the other eye; Figure 11 schematically shows the light beams emitted from the convex lens-shaped micro- lenses arranged in rows as shown in Figure 2 where the micro-lenses within the eye distance are symmetric convex lenses, the lenses out of the eye distance are asymmetric convex lenses, and the row emits the light beams to one eye; Figure 12 schematically shows the light beams emitted from the convex lens-shaped micro- lenses arranged in one of the rows as shown in Figure 2, where the micro-lenses within the eye distance are symmetric convex lenses, the micro-lenses out of the eye distance are asymmetric convex lenses, and the row emits the light beams to the other eye; Figure 13 is the side view of a microprism-shaped micro-lens; Figure 14 is the bottom-view of the microprism-shaped micro-lens, i.e. it shows the design of their base plate; Figure 15 is the side view of the so-called cylindrical micro-lens; Figure 16 is the side view of the symmetrically shaped micro-lens; Figure 17 is the bottom-view of the micro-lenses, i.e. it shows the design of their base plate; Figure 18 is the perspective view of a micro-lens having the form of a wedge-shaped microprism; Figure 19 is the perspective view of a cylindrical micro-lens; Figure 20 is an explanation of the calculation according to the example, where the refraction of the microprism on pixel k is shown; Figure 21 is also an explanation of the calculation of the example where the enlarged cross- sectional view of the highlighted portion marked by XXI in Figure 7 can be seen, showing the measurement of microprisms on pixels k-1, k and k+1; Figure 22 is a block diagram showing the SBS video file format with the arrangement of the pixels directed to the right eye (R) and the left eye (L); Figure 23 is the flow chart of the method according to the invention. The method according to the invention is applicable for displaying a 3D image without an external aid. For the viewers a 3D film i.e. media content is displayed. Media contents substantially consist of two image parts, generally called two half-frames, hereinafter also called as first half-frame and second half-frame. These media contents are displayed on a flat display screen 1 so that the content is displayed in a 3D effect. The display screen 1 consists of light points (hereinafter: pixels 3) formed from elementary RGB light sources, which can be displayed on the display surface 2 of the display screen 1. The display screen 1 consists of 3 pixels arranged in a matrix grid 6 consisting of rows 4 and columns 5 (Figure 1). In the method, a matrix grid 6 preferably formed on a single sheet substrate is placed on the display surface 2 i.e. on the viewer(s) side of the display screen 1, the substrate is made of a water-clear material permeable for the light beam 19 and consisting of micro-lenses 8 adjusted to the size of the pixels 3. The micro-lenses 8 may be microprisms 7 shown in Figures 9 and 10, cylindrical (asymmetric) micro-lenses 8 shown in Figure 11 or symmetrical convex micro-lenses 8 shown in Figure 12. The microprism 7 is also a kind of micro-lens 8, which is indicated by a different number for the sake of clarity only in the description of the invention. The size of the base plate 9 of the microprisms 7 is equal to the surface of a pixel 3 (Fig.10). The size of the base plate 9 of the micro-lenses 8 is equal to the surface of two adjacent pixels 3 (Fig.13). The adjacent pixels 3 in the rows 4 and columns 5 are called first pixels 14 and second pixels 15, thus forming pixel pairs 16. The sequence of these pixel pairs 16 forms rows 4 and columns 5. The arrangement of the first pixel 14 and the second pixel 15 and the pairs of pixels 16 arranged therefrom on the display screen 1, is shown in Figures 2, 5 and 6. To achieve the 3D effect, one half-frame is transmitted to the first pixels 14 and the other half-frame to the second pixels 15 by the control electronics. The design of the control electronics and making the control program must be within the knowledge of a person skilled in the art. In the description of the invention only the knowledge not known to those skilled in the art will be described in detail. Thus, in the matrix grid 6, micro-lenses 7, 8 with a base plate 9 the size of which substantially equals to the size of one or two pixels 3 are used. The pixels 3 are arranged into pixel pairs 16 consisting of first pixels 14 and second pixels 15. On the pixel pairs 16 arranged in the display surface 2 of the display screen 1 symmetrical convex micro-lenses 8 or cylindrical (asymmetrical) micro-lenses 8 are placed. If the micro-lens 8 is formed as a microprism 7, then a separately formed microprisms 7 is placed on the first pixel 14 and the second pixel 15 per pixels 3. On the display surface 2 of the display screen 1, a substrate made of a water-clear material of the same size as the surface is placed, on which micro-lenses 8 adapted to the size of the pixels 3 are formed, for example by laser technology. The micro-lenses 8 are designed so that the light beam 19 emitted by the pixels 3 is projected towards the center line 20 of the display screen 1 in such a way that each light beam 19 emitted by the first pixels 14 is directed into one eye 21 of the viewer(s) and every second pixel 15 light beam 19 is directed into the other eye 22 of the viewer(s). To do this, the respective pixels of the first half-frame are directed to the corresponding first pixels 14 and simultaneously the respective pixels of the second half-frame are directed to the corresponding second pixels 15 by means of the control electronics. In one embodiment, the micro-lenses 8 are symmetrical convex lenses. According to another embodiment, the micro-lenses 8 are asymmetric cylindrical lenses which are placed on two adjacent pixels 3, i.e. a pixel pair 16. According to a further embodiment the micro-lenses 8 having right-angled triangular cross- sections are wedge-shaped elements bordered by flat surfaces consisting of a base plate 9, a side plate 10 and a cover plate 11 form the micro-prisms 7, where the size of the base plate 9 substantially equals to the size of pixel 3. The control of the 3 pixels can be arbitrary according to the state of the art. For this reason, each half-frame can be delivered to the viewers through any pixels 3. According to the invention, any solution is possible in which every second pixel 15 displays the first half-frame and every first pixel 14 displays the second half-frame. Of course, all other controls can be used, but the image of the 3D media content would not be as good as the image produced with the solution according to the present invention. Based on the above, three types of pixel allotments are proposed. The first pixel 14 and the second pixel 15 are represented by one marked in white and the other in black. From the point of view of the present solution, it does not matter which are the first pixels 14 and which are the second pixels 15. In Fig.5, two adjacent pixels 3 in the rows 4, i.e. the first pixel 14 and the second pixel 15 are arranged in a pixel pair 16. In this case, the first half-frame is displayed in one of the 5 columns, while the second half-frame is displayed in the adjacent column 5. In Fig.2, two pixels 3 below each other in columns 5, i.e. the first pixel 14 and the second pixel 15 are arranged in a pixel pair 16. In this case, the first half-frame is displayed in one of the rows 4, while the second half-frame is displayed in the rows 4 below it. In Fig. 6, the first pixel 14 and the second pixel 15 are arranged like a chessboard on the display screen 1. In this case, the corners of the first pixels 14 are in contact with each other, just as the corners of the second pixels 15 are in contact with each other. The micro-lenses 7, 8 are designed so that the light beam 19 of each pixel 3 of the display screen 1 is directed towards the central part of the display screen 1, i.e. towards the eyes of the viewers, assuming that they are facing the display surface 2 of the display screen 1 while watching. Of course, taking into account the laws of refraction. In one embodiment of the present invention according to Figures 3 and 7 (the first pixel 14 and the second pixel 15 are not shown in different colors) and in the arrangement according to Figure 5, from the center line 20 perpendicular to the rows 4 of the display screen 1 the first micro-prism 17 and the second microprism 18 are placed on the first pixel 14 and the second pixel 15 of adjacent pixel pairs 16 on the side of the display surface 2 facing the viewer(s) in a width corresponding to the average eye distance 23 (55 – 68 mm) of the viewer(s). In this arrangement, the side plates 10 of the first microprism 17 and the second microprism 18 are turned towards each other in each row 4. On the display surface 2 of the display screen 1 outside the area defined by the eye distance 23, towards the edge of the display screen 1, the other microprisms 7 arranged in rows 4 or columns 5 are designed so that the meeting edges 24 of the base plate 9 and the cover plate 11 are parallel with the center line 20 towards the edge of the display screen 1. The first half-frame is projected to the pixels 3 in a column 5, and at the same time the second half-frame is projected to the pixels 3 in the adjacent column 5. This is repeated in the other columns 5 of the display screen 1. The slope of the cover plate 11 of the microprisms 7 is designed so that the first half-frame transmitted by the pixels 3 in a column 5 is directed to one eye 21, and the second half-frame transmitted by the pixels 3 in the adjacent column 5 is directed to the other eye 22. In another embodiment of the invention according to Figures 3 and 7 but in the arrangement according to Figure 2, from the center line 20 perpendicular to the rows 4 of the display screen 1 the first micro-prism 17 and the second microprism 18 are placed on the first pixel 14 and the second pixel 15 of adjacent pixel pairs 16 on the side of the display surface 2 facing the viewer(s) in a width corresponding to the average eye distance 23 (55 – 68 mm) of the viewer(s) (Figures 13, 14, 18). In this arrangement, the side plates 10 of the first microprism 17 and the second microprism 18 are turned towards each other On the display surface 2 of the display screen 1 outside the area defined by the eye distance 23, towards the edge of the display screen 1, the other microprisms 7 arranged in rows 4 or columns 5 are designed so that the meeting edges 24 of the base plate 9 and the cover plate 11 are parallel with the center line 20 towards the edge of the display screen 1. The first half-frame is projected to the pixels 3 in a row 4, and at the same time the second half-frame is projected to the pixels 3 in the adjacent row 4. This is repeated in the other rows 4 of the display screen 1. The slope of the cover plate 11 of the microprisms 7 is designed so that the first half-frame transmitted by the pixels 3 in a row 4 is directed to one eye 21 (Figure 10), and the second half-frame transmitted by the pixels 3 in the adjacent row 4 is directed to the other eye 22 (Figure 9). In another embodiment of the present invention according to Figures 4 and 8 (the first pixel 14 and the second pixel 15 are not shown in different colors) and in the arrangement according to Figure 5, from the center line 20 perpendicular to the rows 4 of the display screen 1 the convex micro-lenses 8 having a symmetric convex cover plate 12 are placed on the first pixel 14 and the second pixel 15 of adjacent pixel pairs 16 on the side of the display surface 2 facing the viewer(s) in a width corresponding to the average eye distance 23 (55 – 68 mm) of the viewer(s) (Figures 16, 17). On the display surface 2 of the display screen 1 outside the area defined by the eye distance 23, towards the edge of the display screen 1 the other micro- lenses 8 arranged in rows 4 or columns 5 are cylindrical asymmetric convex micro-lenses 8 (Figures 15, 17, 19). The meeting edges 24 of their base plate 9 and convex cover plate 12 are arranged parallel with the center line 20 towards the edge of the display screen 1. Within one column 5 micro-lenses 8 of the same design are used. The first half-frame is transmitted to the pixels 3 in one of the columns 5, and the second half-frame is transmitted to the pixels 3 in the adjacent column 5 at the same time. This is repeated in the other columns 5 of the display screen 1. The convex cover plate 12 of the micro-lenses 8 is designed so that the first half-frame transmitted by the pixels 3 in a column 5 is directed to one eye 21, and the second half-frame transmitted by the pixels 3 in the adjacent column 5 is directed to the other eye 22. In a further solution of the present invention according to Figures 4 and 8 in the arrangement according to Figure 2 from the center line 20 perpendicular to the rows 4 of the display screen 1 the convex micro-lenses 8 having a symmetric convex cover plate 12 are placed on the first pixel 14 and the second pixel 15 of adjacent pixel pairs 16 on the side of the display surface 2 facing the viewer(s) in a width corresponding to the average eye distance 23 (55 – 68 mm) of the viewer(s). On the display surface 2 of the display screen 1 outside the area defined by the eye distance 23, towards the edge of the display screen 1 the other micro-lenses 8 arranged in rows 4 or columns 5 are cylindrical asymmetric convex micro-lenses 8. The meeting edges 24 of their base plate 9 and convex cover plate 12 are arranged parallel with the center line 20 towards the edge of the display screen 1. The first half-frame is transmitted to the pixels 3 in one of the rows 4, and the second half-frame is transmitted to the pixels 3 in the adjacent row 4 at the same time. This is repeated in the other rows 4 of the display screen 1. The convex cover plate 12 of the micro-lenses 8 is designed so that the first half-frame transmitted by the pixels 3 in a row 4 is directed to one eye 21 (Figure 11), and the second half-frame transmitted by the pixels 3 in the adjacent row 4 is directed to the other eye 22 (Figure 12). Preferably, microprisms 7 of the same design are used within one column 5. The half-frames have a frequency of at least 25Hz. The device for carrying out the method according to the invention consists of a matrix grid 6 placed on the display surface 2 of the display screen 1, the matrix grid 6 is preferably made of a water-clear material permeable for the light beam 19 comprising micro-lenses 8 adjusted to the size of the pixels and formed as microprisms 7 with triangular cross-section; and a control electronics for transmitting the given points of the half-frames to the corresponding pixels 3. Designing the control electronics and making the program for operating it is well within the knowledge of a person skilled in the art. The micro-lenses 8 are arranged in a mesh in the matrix grid 6. The micro-lenses 8 shaped as microprisms 7 are lenses with right-angled triangular cross- section. They are wedge-shaped elements bordered by flat surfaces consisting of a base plate 9, a side plate 10 and a cover plate 11. Micro-lenses 8 may be symmetrical convex micro- lenses 8 having a base plate 9 and a convex cover plate 12. Further, the micro-lenses 8 may be asymmetric cylindrical micro-lenses formed of a base plate 9, a convex cover plate 12 and a convex side plate 13. The asymmetric cylindrical micro-lenses 8 are formed in an area outside the display surface 2 of the display screen 1. The size of the base plate 9 of the micro- lenses 8 formed as microprisms 7 corresponds to the size of the light emitting surface of a pixel 3. The size of the base plate 9 of the symmetric convex micro-lenses 8 and the asymmetric cylindrical micro-lenses corresponds to the size of the light emitting surface of two adjacent pixels 3. The pixels 3 forming the rows 4 and columns 5 of the matrix grid 6 are arranged in pixel pairs 16 consisting of a first pixel 14 and a second pixel 15, so that a micro-lens 8 having the form of a first microprism 17 is placed on the viewer side surface of each first pixel 14, and a micro- lens 8 having the form of a second microprism 18 is placed on the viewer side surface of each second pixel 15. According to another solution a convex micro-lens 8 is placed on both pixels of the pixel pairs 16 comprising the first pixel 14 and the second pixel 15 so that the base plates 9 of the micro- lenses 8 are laid on the viewer side surface of the pixel pairs 16 in the display surface of the display screen 1. In order to achieve the 3D effect, the media content forming the first half-frame must be transmitted to either the first pixels 14 or the second pixels 15 and the media content forming the second half-frame is transmitted to pixels 3 opposite to the pixels 3 receiving the first half- frame, that is, in this case to the second pixels 15 or the first pixels 14. Furthermore, the micro- lenses 8 must be arranged in the matrix grid 6 in such a way that those of the micro-lenses 8 which are in front of the pixels 3 receiving the first the half-frame direct the light beams 19 towards one eye 21. The micro-lenses 8 in front of the pixels 3 receiving the second half-frame direct the light beams 19 to the other eye 22. For this purpose, the pixel pairs 16 consisting of 8 micro-lenses are arranged either in columns 5 or in rows 4, but they can also be arranged like a chessboard, and the pixels 3 are controlled as described above. To direct the light beams 19 to appropriate direction, i.e. towards one eye 21 or the other eye 22, the light beams 19 emitted by the pixels 3 must be directed towards the center line 20 of the display screen 1. If the matrix grid 6 is produced from micro-lenses 8 formed as microprisms 7, then within the eye distance 23 the microprisms 7 are arranged on the display 1 screen with their side plates 10 facing each other and the microprisms 7 outside the eye distance 23 are arranged with their edges 24 towards the edges of the display screen 1, i.e. their side plates 10 are closer to the center line 20. If convex micro-lenses 8 and asymmetric cylindrical micro-lenses 8 are used, convex lens-shaped micro-lenses 8 are arranged within the eye distance 23. Outside the eye distance 23, asymmetric cylindrical micro-lenses 8 are arranged so that the maximum height of their cover plate 11 or their convex cover plate 12 measured from the base plate is at most at the center of the micro-lenses 8 or it is formed from the center of the micro-lenses 8 towards the center line 20 of the display screen 1, i.e. their edges 24 are closer to the edge of the display screen 1 than the maximum height of the cover 11 or convex cover 12 of the micro-lenses 8 measured from the base plate 9. These arrangements ensure that the light beams 19 are projected toward the center line 20 based on the refractive properties of the optical lens. In the example embodiment the use of micro-lenses 8 formed as microprisms 7 is shown. The same method is used when convex lenses or cylindrical convex lenses are used. The mathematical definitions required for the precise control of the 19 light beams are detailed. By determining this vectorial direction, we define the shape and material of the microprisms 7 to be placed on the pixels 3. In our example, shown in Figure 7, the display screen 1 has the following specification: frame diagonal 6.53", resolution 2340x1080 FHD, aspect ratio19.5:9. Naturally, not all the pixels 3 are shown in Figure 7, but it is assumed that our explanation will still be clear for a person skilled in the art. The transmission path of the light beam 19 emitted from each of the pixels 3 (2340) of a row 4 toward the corresponding eye 21, 22 of the viewer is determined. That is, for every pixel 3, the magnitude of the angle of emergence 25 α(k) (positive direction) enclosed by the light beam 19 and the display screen 1 is given. The following notations are introduced to perform the calculations: d: screen diagonal (cm) w: screen width (cm) n: number of horizontal pixels 3 (pcs) D: viewing distance 27 of the viewer’s eye measured from the display screen 1 (considered a constant value of 48 cm) eye distance 23 (considered a constant value of 6 cm) : pixel width (cm)

k: numbering of the horizontal pixels 3 starting from the left side of the display screen1 (k=1,2,...,2340) β(k): angle of incidence 28 of the light beam 19 from pixel 3 k arriving perpendicular to the eyeball, expressed in degrees α(k): angle of emergence 25 enclosed by the light beam 19 going towards the eyeball from pixel 3 k and the display screen 1 , expressed in degrees. Knowing the diagonal (6.53") of the display screen 1, the following values can be determined, which will serve as a basis for subsequent calculation. d = 16.5862 cm w = 15.06 cm n = 2340 pcs

Before determining the values of the angle of incidence 28 β(k), note that the position of the light beam 19 arriving perpendicular to the left eye (in this case the other eye 22) is, for example, 10.53 cm (pixel 1636) from the left edge of the display screen 1, the position of the light beam 19 arriving to the right eye (in this case the one eye 21) is 4.53 cm (pixel 704) from the left edge of the display screen 1.In the following, in the detailed calculations, the symbols shown in Fig.7 and already referred to above will not be given for the sake of simplicity, only in some places where it is considered reasonable. In the first step the values of tan β(k) are examined when the light from the even numbered pixels between 2 – 1636 arrives in the left eye. Then:

Consequently, the values of tan β(i+2) can also be computed recursively (knowing the previous term), that is:

In the second step the values of tan β(k) for the pixels with even indexes between 1638-2340 are given. For symmetrical reasons, reflected to the line of light coming perpendicularly to the left eye, it occurs: tan β(1637+k) = tan β(1637-k) (k = 1,3,...,703) In the third step also for symmetrical reasons the values of tan β(k) for the pixels with odd indexes between 1-2339 are given. tan β(k) = tan β(2341-k) (k = 1,3,...,2339) It follows from the above that the values of tan β(k) (k = 1,2,...,2340) become known. In the fourth step the values of β(k) (k = 1,2,...,2340) are calculated in degrees: β(k) = arctan (tan β(k)) (k = 1,2,...,2340) In the fifth step the values of α(k) (k = 1,2,...,2340) taking advantage of the fact that α(k) and β(k) are each other’s complementary angles in each triangle: α(k) = 90-β(k) (k = 1,2,...,2340) Step six: the resulting angles are acute angles enclosed by the direction of the light and the line of the display screen, no matter from which pixel of the display screen to which eye they proceed. Therefore, for the sake of clarity when pixel k passes the line of light coming perpendicularly to the eyes (in this case pixels 704 and 1636) the values of α(k) are also given in degrees by means of the complementary angles (obtuse angle). Our aim is to direct the light emitted from pixel k in an angle α(k). For this purpose, a rectangular prism with a refractive index corresponding to the refractive index of the display screen is placed on the surface of each pixel (in this example the refractive index for the glass is 1,500,000, and 1,000 293 for the air). In the following the refraction of pixel k and the corresponding angles are shown in Figure 20. ^^: the included angle between the emergent and entering beam is the angle of deflection (deviation) known;

in a medium with a refractive index n₁ the angle of deflection ^^ of the light passing through a prism having a subtense Φ and a refractive index n₂ is: ^^{^ ^^}

using the paraxial approximation (the principal in geometrical optics according to which all angles occurring are small enough to replace the sine and tangent of the angle with the angle itself, and its cosine with 1). Step seven: , the value of tanΦ can be calculated for each pixel k.

Step eight: on the other hand, _{from which: is presented.}

In Figure 21 the pixel width w/n and the corresponding height h (height of side plate 10 and height of edge 24) is illustrated. In each case the left and right end point of pixel 3 k of the display screen is marked with h(k,left) and h(k,right) irrespective of to which eye of the viewer is the light projected by pixel 3. Considering the width of the display screen 1 to clearly define the angles of the microprisms 7 the angle enclosed by the cover plate 11 (hypotenuse) and the plane of the display screen 1 is taken as basis . Depending on whether the

hypotenuse of the microprism 7 on a given pixel 3 forms an acute or obtuse angle with the plane of the display screen 1, the height of the triangle (the height of the side plate 10) in absolute value reaches the right or left end point of pixel 3. The value of the other end point is 0. At the left and right edge of each pixel the height of the microprism 7 (the height of the side plate 10 and the height of the edge 24) is given. Of course, in each case one end point (edge 24) has a value of 0, the other end point (side plate 10 height) has the value ℎ^ ^^^ calculated using the formula of step eight. If it falls to the right end point, if ℎ^ ^^^ ^ 0, then it falls to the left end point in absolute

value, i.e.:

We defined the properties of prism 3 by giving the value of Φ^ ^^^ in degrees and the values of h(k,left) and h(k,right) in cm. Based on the mathematical formulation related to Figure 21 the processing program required for forming the microprisms included in the matrix grid 6 can be prepared. By changing the parameters used in the example (the size of the frame diagonal; the resolution and aspect ratio of the display screen 1; the viewing distance 27; the refractive index of the glass) the positions of the viewing perpendiculars (mirror axis) must be recalculated, but then the procedure can be used to define the properties of the prism. The video signals (the so-called half-frames) of the right and left channels of the SBS format 3D content are controlled by a control algorithm which is embedded in the particular operating system. Practically, the software is a two-channel 3D video control algorithm designed for interpreting per columns 5 or rows 4 the right and left signals of the 3D content recorded in the Side by Side format independently from each other, and for transmitting them to the corresponding first pixel 14 and second pixel 15 of the display screen 1 having the system of prisms. Creating the algorithm is a routine task for a person skilled in the art. Currently, this platform can be Android or MS Windows based. The task of the program is to display the right and left images of the digital stereoscope content in the corresponding pixel cluster. The functional role of the SBS video file format in the software system is shown in the block diagram of Figure 22 where the arrangement of the pixels directed to the right eye (R) and left eye (L) can be seen. The flow chart of the operation is shown in Figure 23. Accordingly, the SBS 3D media content is separated into right and left video channels by the control algorithm, then transmitted to the first pixels 14 and the second pixels 15 separately but simultaneously in a manner shown in Figure 22. Although the video signals transmitted to columns 5 are shown in Figures 22 and 23, the solution according to the example can be applied similarly to the first pixels 14 and the second pixels 15 in the rows 4 or in a chessboard-like arrangement. The advantage of the present invention is that by using it the display itself is able to perform the role of all the external physical devices used so far. In addition to achieving the physical goal, another main aspect is that the video control program is compatible with the existing 3D contents (3D movies, stereoscope photos) so producing new, special format 3D contents or even converting the old contents are not needed for the display screen of the present invention. The system driving software is compatible with any SBS (Side by Side) content the extension of which is usually .mkh, .mp4,...etc. The advantage of the solution according to the invention is that the display screen itself and the manner of display ensure that the two eyes always receive the image corresponding to the eye. The method and the device according to the invention eliminates the disadvantages of the 3D display used till now, since it provides the 3D effect in itself, without using a separate device, by viewing the display screen from a certain distance and angle range. So, there is no need for a separate tool. The new technical component used in the solution of the present invention is the structure of the 3D display screen itself, the passive lens matrix and the control electronics. The switching frequency of the half-frames depends on the recording. In case of the solution according to the invention all the recordings made with the conventional 3D recording can be played back.

Claims

Claims 1 Method for displaying a 3D image, in the method 3D display of media contents consisting of two image parts, hereinafter called two half-frames: first half-frame and second half-frame on a flat display screen is performed without an external aid for the viewer(s), the display is performed on the display surface of the display screen consisting of light points (hereinafter: pixels) formed from elementary RGB light sources, the display screen consists of pixels arranged in a matrix grid of rows and columns, during the method a matrix grid preferably formed on a single sheet substrate is placed on the display surface i.e. on the viewer(s) side of the display screen, the substrate is made of a water-clear material permeable for the light beam and consisting of micro-lenses – including microprisms – adjusted to the size of the pixels, the transmission of the given points of the half-frames to the corresponding pixels is performed by control electronics, characterized in that in the matrix grid (6), micro-lenses (7, 8) of a base plate (9) size substantially equal to the size of one or two pixels (3) are used, said pixels (3) are arranged in pixel pairs (16) consisting of a first pixel (14) and a second pixel (15), a common or a micro-lens (7, 8) designed separately for said first pixel (14) and said second pixel (15) per pixel is laid on the pixel pairs (16) placed in the display surface (2) of the display screen (1), said micro-lenses (7, 8) are designed so that the light beam (19) emitted by said pixels (3) is projected toward the centerline (20) of said display screen (1) in such a manner that the light beam (19) emitted by each first pixel (14) is projected into one eye (21) of the viewer(s) and the light beam (19) emitted by each second pixel (15) is projected into the other eye (22) of the viewer(s) in such a manner that certain pixels of the first half-frame are transmitted to the corresponding first pixels (14) and certain pixels of the second half-frame are transmitted to the corresponding second pixels (15) at the same time by means of a control electronics. 2 Method according to claim 1 characterized in that said micro-lenses (7, 8) are symmetric convex lenses or asymmetric cylindrical lenses which are placed on two adjacent pixels (3) i.e. a pixel pair (16). 3 Method according to claim 1 characterized in that said micro-lenses (7, 8) are wedge-shaped elements having right-angled triangular cross-sections, bordered by flat surfaces consisting of a base plate (9), a side plate (10) and a cover plate (11), and formed as microprisms (7) consisting of a first microprism (17) and a second microprism (18) having a baseplate (9) of the same size as the pixel (3). 4 Method according to claim 3 characterized in that from the center line (20) perpendicular to the rows (4) of the display screen (1) the first micro-prism (17) and the second microprism (18) are placed on the first pixel (14) and the second pixel (15) of adjacent pixel pairs (16) on the side of the display surface 2 facing the viewer(s) in a width corresponding to the average eye distance (23) 55 – 68 mm of the viewer(s) so that the side plates (10) of the first microprism (17) and the second microprism (18) are turned towards each other in each row (4), while on the display surface (2) of the display screen (1) outside the area defined by the eye distance (23) 55 – 68 mm, towards the edge of the display screen (1), the other microprisms (7) arranged in rows (4) or columns (5) are designed so that the meeting edges (24) of the base plate (9) and the cover plate (11) are parallel with the center line (20) towards the edge of the display screen (1), the first half-frame is projected to the pixels (3) in a column (5), and at the same time the second half-frame is projected to the pixels (3) in the adjacent column (5), and this is repeated in the other columns (5) of the display screen (1), further, the slope of the cover plate (11) of the microprisms (7) is designed so that the first half-frame transmitted by the pixels (3) in a column (5) is directed to one eye (21), and the second half-frame transmitted by the pixels (3) in the adjacent column (5) is directed to the other eye (22). 5 Method according to claim 3 characterized in that from the center line (20) perpendicular to the rows (4) of the display screen (1) the first micro-prism (17) and the second microprism (18) are placed on the first pixel (14) and the second pixel (15) of adjacent pixel pairs (16) on the side of the display surface (2) facing the viewer(s) in a width corresponding to the average eye distance (23) 55 – 68 mm of the viewer(s) in such a manner that the side plates (10) of the first microprism (17) and the second microprism (18) are turned towards each other in each row (4), while on the display surface (2) of the display screen (1) outside the area defined by the eye distance (23) 55 – 68 mm, the other microprisms (7) arranged in rows (4) or columns (5) towards the edge of the display screen (1), are designed so that the meeting edges (24) of the base plate (9) and the cover plate (11) are parallel with the center line (20) towards the edge of the display screen (1), the first half-frame is projected to the pixels (3) in a row (4), and at the same time the second half-frame is projected to the pixels (3) in the adjacent row (4), and this is repeated in the other rows (4) of the display screen (1), further, the slope of the cover plate (11) of the microprisms (7) is designed so that the first half-frame transmitted by the pixels (3) in a row (4) is directed to one eye (21) and the second half-frame transmitted by the pixels (3) in the adjacent row (4) is directed to the other eye (22). 6. Method according to claim 2 characterized in that from the center line (20) perpendicular to the rows (4) of the display screen (1) the convex micro-lenses (8) having a symmetric convex cover plate (12) are placed on the first pixel (14) and the second pixel (15) of adjacent pixel pairs (16) on the side of the display surface (2) facing the viewer(s) in a width corresponding to the average eye distance (23) 55 – 68 mm of the viewer(s), while on the display surface (2) of the display screen (1) outside the area defined by the eye distance (23) 55 – 68 mm, the other micro-lenses (8) arranged in rows (4) or columns (5) towards the edge of the display screen (1) are cylindrical asymmetric convex micro-lenses (8), the meeting edges (24) of their base plate (9) and convex cover plate (12) are arranged parallel with the center line (20) towards the edge of the display screen (1), the first half-frame is transmitted to the pixels (3) in one of the columns (5), and the second half-frame is transmitted to the pixels (3) in the adjacent column (5) at the same time, and this is repeated in the other columns (5) of the display screen (1), further, the convex cover plate (12) of the micro-lenses (8) is designed so that the first half-frame transmitted by the pixels (3) in a column (5) is directed to one eye (21), and the second half-frame transmitted by the pixels (3) in the adjacent column (5) is directed to the other eye (22). 7 Method according to claim 2 characterized in that from the center line (20) perpendicular to the rows (4) of the display screen (1) the convex micro-lenses (8) having a symmetric convex cover plate (12) are placed on the first pixel (14) and the second pixel (15) of adjacent pixel pairs (16) on the side of the display surface (2) facing the viewer(s) in a width corresponding to the average eye distance (23) 55 – 68 mm of the viewer(s), on the display surface (2) of the display screen (1) outside the area defined by the eye distance (23) 55 – 68 mm, the other micro-lenses (8) arranged in rows (4) or columns (5) towards the edge of the display screen (1) are cylindrical asymmetric convex micro-lenses (8), the meeting edges (24) of their base plate (9) and convex cover plate (12) are arranged parallel with the center line (20) towards the edge of the display screen (1), the first half-frame is transmitted to the pixels (3) in one of the rows (4), and the second half-frame is transmitted to the pixels (3) in the adjacent row (4) at the same time, this is repeated in the other rows (4) of the display screen (1), further, the convex cover plate (12) of the micro-lenses (8) is designed so that the first half-frame transmitted by the pixels (3) in a row (4) is directed to one eye (21) and the second half-frame transmitted by the pixels (3) in the adjacent row (4) is directed to the other eye (22). 8 Device for displaying a 3D image, implementing the method according to claims 1 – 7, the device is suitable for 3D display of media contents consisting of two image parts, hereinafter called two half-frames, on a flat monitor display for the viewer(s) without an external aid, the display surface of the display screen consists of light points (hereinafter: pixels) formed form elementary RGB light sources, the pixels are arranged in a matrix grid of rows and columns, a matrix grid preferably formed on a single sheet substrate is placed on the display surface of the display screen, the substrate is made of a water-clear material permeable for the light beam, the matrix grid consists of micro-lenses adjusted to the size of the pixels, the micro- lenses are preferably formed as microprisms having a triangular cross-section, further, the given points of the half-frames are transmitted to the corresponding pixels by control electronics, characterized in that the micro-lenses (8) having right-angled triangular cross- sections are wedge-shaped elements bordered by flat surfaces consisting of a base plate (9), a side plate (10) and a cover plate (11) and are formed as a microprism, the micro-lenses (8) are convex lenses formed of a base plate (9), a convex cover plate (12), and optionally a convex side plate (13), the size of the base plate (9) substantially equals to the size of one pixel (3) or two adjacent pixels (3), the pixels forming the rows (4) of the matrix grid (6) are arranged in pixel pairs (16) consisting of a first pixel (14) and a second pixel (15) in such a way that one micro-lens (8) shaped as a first microprism (17) is placed on the surface of the first pixel (14) and a second micro-lens (8) shaped as a second microprism (18) is placed on the surface of the second pixel (15), or a micro-lens (8) in the form of a convex lens or a cylindrical asymmetric convex micro-lens is placed on the pixel pairs (16) in such a way that the base plate (9) of the micro-lenses (7, 8) arranged in the matrix grid (6) lie on the pixels (3) in the display surface (2), the light beam (19) emitted by the pixels (3) are directed towards the center line (20) of the display screen (1) in such a way that the maximum height of the cover plate (11) or the convex cover plate (12) of the micro-lenses (7, 8) measured from the base plate (9) is at most at the center of the micro-lenses (7, 8) or it is formed from the center of the micro- lenses (8) toward the center line (20) of the display screen (1), i.e. the meeting edges (24) of the base plate (9) and the cover plate (11) or the meeting edges (24) of the base plate (9) and the convex cover plate (12) are parallel with the center line (20) towards the edge of the display screen (1), further, one half-frame is transmitted to the first pixels (14), the other half-frame is transmitted to the second pixels (15) simultaneously by means of the control electronics. 9 Device according to claim 8 characterized in that two adjacent pixels (3) in the rows (4), i.e. the first pixel (14) and the second pixel (15) are arranged in a pixel pair (16). 10 Device according to claim 8 characterized in that two pixels (3) below each other in the columns (5) i.e. the first pixel (14) and the second pixel (15) are arranged in a pixel pair (16). 11 Device according to claim 8 characterized in that the first pixel (14) and the second pixel (15) are arranged on the display screen (1) like a chessboard.