Naked-eye 3D display

Abstract

The present invention relates to a display design in which the black matrix, the interstitial area between pixels of a display panel, is not expanded with other content, thus improving the visibility of very small objects such as text.

Description

[Technical field]

[0001] The present invention relates to a naked-eye 3D display device (also called display or naked-eye 3D display for short) that improves image quality by preventing the black gap area between pixels of the display, also called the "black matrix", from being enlarged by an optical lens system. This improves the recognition rate of small objects such as characters, and allows the image quality to be similar to that of a 2D display without a lens system, particularly in the 2D mode of the display suitable for 3D expression. [Background technology]

[0002] In recent years, the image quality of display devices has improved significantly. Resolutions have increased by more than 16 times, and the color dynamic range has been expanded by HDR and UHD to match the color sensitivity of the eye. There have also been attempts in the area of ​​visualizing spatial depth in monitors and other display devices. However, displays developed for this purpose required so-called 3D glasses. 3D glasses provide two different perspective projections for the left and right eyes. The right eye has a right perspective projection and the left eye has a left perspective projection, and the human brain creates a so-called internal spatial image from the two perspective projections, and each object of the scene is assigned a different spatial depth from the others. This allows the viewer to recognize which objects are in the foreground and which are in the background. Thus, the spatial vision principle of displays through 3D glasses shows a fundamentally correct and desired spatial depth effect.

[0003] However, viewers are not always ready to use 3D glasses. For example, 3D glasses have been accepted in the construction and medical fields, but not in the consumer field where people watch games and movies in 3D at home.

[0004] Therefore, other methods have been developed to provide two different perspective projections to each eye without 3D glasses, for example, a lens system, such as B. Lenticular Lens Group or Element Lens Group, placed in front of the display. Such a lens system typically consists of multiple lenses that cover the display from the top pixel row to the bottom pixel row, and such a lenticular lens system is shown in FIG.

[0005] For naked-eye 3D displays, two technologies have been developed: one is lenticular lens technology, and the other is integral imaging technology, also known as elemental lenses.

[0006] JC Maxwell's lenticular lens technology has remained almost unchanged since its introduction (JC Maxwell, "On the cylinder", Quart. j. Of Pure & Applied Math. IX, 11-126 (1868)). C. van Berkel has presented a comfortable multi-viewer configuration with tilted lenticular lenses (C. van Berkel, "Image preparation for 3D-LCD", Proc. SPIE 3639, 84-91 (1999)), for which he also developed formulas that allow to calculate which perspective projection is displayed for which sub-pixel.

[0007] Some have further improved the optical quality by printing black stripes on the back of the lens system (Dahnert, Ulrich, "Device for Three-dimensional Representation of Multiple Views and Method for the Production thereof", WO2011 / 082992A2).

[0008] Basically, the use of lenticular lenses in naked-eye 3D displays creates a so-called viewing zone in front of the display, especially if the lens system is not aligned horizontally or vertically with respect to the pixel positions but tilted at a certain angle. If the viewer's both eyes are in the same viewing zone, they get a good 3D impression, otherwise they get a blurry impression or so-called ghosting.

[0009] Therefore, in Dahnert, black stripes are printed between two adjacent lenses on the rear surface of the lens system to avoid such ghosting. The plane of the lens system is always the rear surface of the optical lenticular system. However, the black stripes are not arranged on a black matrix, but arranged to separate adjacent lenticular lenses. In Dahnert, the unwanted perspective vision is reduced when the viewer is at the edge of the viewing zone, and the 3D impression is sharpened in the entire area in front of the display.

[0010] Another method besides lenticular lens technology is the integral imaging technology. In the case of integral imaging displays, an optical system consisting of several "hemispheres", also called element lenses, is used, which are uniformly arranged on the display panel (Figure 6). Such an element lens system shows a pixel magnification effect in the horizontal and vertical directions. At every position in front of the display, a certain number of pixels can be seen, and these pixels are magnified to create a stereoscopic overall image for both the left and right eyes at every position. But what is special about this technology is that not only can you move left and right to see behind the foreground object, but you can also move up and down to see behind the foreground object ("walk-around effect"). Thus, it offers more flexibility than lenticular lens technology. But it has the disadvantage that, like lenticular lenses, the visible resolution is reduced in the vertical direction as well as in the horizontal direction. An integral imaging display with a suitable number of element lenses has fewer pixels in HD displays at every viewing position than a VGA display. Also, if you want to record a meaningful image for this display, the same element lens system used in this display must be used in the recording camera. Such cameras are not yet commercially available, so to date there are few images suitable for integral imaging displays.

[0011] This technology has improved significantly in the areas of lens manufacturing and display technology: on the one hand, lens systems can now be made much smaller, on the other hand, the color quality of displays has improved significantly, as has their resolution.

[0012] An image point of a display is simply called a pixel. The pixel structure refers to the surface of the display on which the pixels are physically located, also called the display panel. The areas that are responsible for the basic colors of a pixel, called subpixels, are arranged adjacent to each other. The pixel structure is generally arranged in the form of a number of pixel rows and a number of pixel columns. A black matrix is ​​located between such adjacent pixel rows and between adjacent pixel columns. The pixel rows and pixel columns do not necessarily have to be straight lines, nor do they have to be strictly aligned horizontally or vertically.

[0013] The conventional display shown in FIG. 1 has n pixels per row and m pixel rows in total. Different lens systems are used depending on whether the optimal viewing distance is different, whether the lens width covers a different number of pixels, whether it is optimized for one viewer ("single viewer") or for multiple simultaneous viewers ("multiple viewers"), whether the lens faces the display or faces away from the display, and whether the lens is parallel or at an angle to the pixel columns (see FIG. 2). Each individual viewer has different viewing angles for the left and right eyes due to different viewing positions of the left and right eyes. In this case, the left and right eyes can see different pixels on the display. If the pixels seen by the left eye belong to the left perspective projection and the pixels seen by the right eye belong to the right perspective projection, the eyes can see different perspective projections and the brain can generate an internal spatial image. The magnifying effect of the lens system allows each eye to see a complete image covering the entire display, i.e., a complete perspective projection, so that the viewer sees 3D. This technique is known as autostereoscopy, as the viewer does not need any visual aids.

[0014] Unfortunately, however, display pixels are not aligned horizontally or vertically. There are gaps of different sizes in the horizontal and vertical directions. This is due to the design and manufacturing techniques of the display. The horizontal gap width is expressed as h>0 and the vertical gap width as v>0. If a lens system is placed in front of the display, the gap area is also expanded by the lens. Such gap areas are also called "black matrix" because they are generally black with no light. However, the expansion of the gap area causes small objects to be deformed. For example, there is the aforementioned "black matrix", i.e., the gap area between the pixels of a display panel whose average width in the horizontal direction is h>0 and whose vertical width in the horizontal direction is v>0.

[0015] This effect is particularly detrimental to characters with thin lines: the widening of the gaps, the "black matrix", means that the lines are no longer straight, making the text less readable. Summary of the Invention [Problem to be solved by the invention]

[0016] Therefore, the object of the naked eye 3D display of the present invention is to provide an optical system which improves image quality even when displaying very small objects, since the gap area between the pixels of the display device is not enlarged. [Means for solving the problem]

[0017] The invention relates to a display in which the visibility of particularly small objects such as characters is improved, since the interstitial area between the pixels of the display panel, also called the "black matrix", is at the same time at least partially not enlarged.

[0018] The present invention provides a naked-eye 3D display having a display panel in which a number of pixels representing the content of a stereoscopic image displayed in two or more perspective projections are separated from each other by gap regions, and an optical lens system of two configurations arranged in front of the display panel towards a viewer, the display panel improving the naked-eye 3D viewing quality, a) the optical lens system has a flat surface covering the display panel and an opposite surface comprising a plurality of lenticular lenses arranged side by side in a horizontal direction, the lenticular lenses having convexly curved lens surfaces on an outer lens surface, the outer lens surface having a plurality of strip-shaped recesses, the recesses being offset parallel to one another with respect to a viewer's position in front of the display, and at least partially covering the horizontal gap areas, the vertical gap areas or the horizontal and vertical gap areas between pixels; or b) providing a naked-eye 3D display, wherein the optical lens system comprises a plurality of pillow-shaped lenses that are horizontally convexly curved and arranged side-by-side in a layer, each of the lenses covering at least a plurality of, in particular 1 to 16, horizontally adjacent pixels, and the horizontal gap areas between pixel rows are kept intact by the pillow-shaped lenses.

[0019] An auto-3D display for improving the auto-3D viewing quality is set out in claim 1, preferred embodiments of which are set out as subject matter of the dependent claims or are explained below.

[0020] In embodiment a) of the present invention, the lenticular lens of the optical system is broken exactly where the horizontal gap area of ​​the display panel is located, thus preventing the magnification effect exactly at this location.

[0021] In particular, in the middle or at the edge of the lens, at least 50%, preferably at least 80%, of the horizontal lines of said black matrix are kept intact by recesses, which may consist of recesses on the horizontal black matrix.

[0022] According to embodiment b) of the invention, a number of pillow-shaped lenses, each of which only overlies one pixel or a few, e.g. 2 to 32, in particular 2 to 16 adjacent pixels, e.g. only overlies 1 or 2 pixels vertically and 1 to 16 or 2 to 8 pixels horizontally, form a layer in front of the display.

[0023] The horizontal gap area (black matrix) is not covered by the lens system, i.e. it is kept intact by the recess with respect to the curved lens surface above it. According to one embodiment, this lens system is compatible with image content recorded by a stereo camera with two or more lenses, since it does not show a pixel magnification effect in the vertical direction. This is because two or more lenses are always arranged horizontally and do not show a vertical "walk-around" effect, i.e. you cannot see behind an object in the foreground from above or below. Each pillow-shaped lens has a horizontally convexly curved surface in the gap area (scattering lens), but not necessarily also in the vertical direction in the gap area. Conversely, it is better that the lens surface is not curved in the vertical direction.

[0024] The pillow lenses can be arranged so that they end at the horizontal line of the black matrix (the lowest point of the curved lens surface). The pillow lenses do not have to be arranged all along a row (Figures 8-9), but can also be arranged alternately with each other (Figure 10). [Brief description of the drawings]

[0025] [Figure 1] This is a plan view of a display with vertical lenticular lenses, where 1, ..., m are pixel rows, 1, ..., n are pixel columns, 1,1, ..., m,n are pixels of the display, L1, ..., Lk are lenticular lens numbers, and the break lines are element lenses. [Diagram 2]This is a plan view of a display with tilted lenticular lenses, where 1, ..., m are pixel rows, 1, ..., n are pixel columns, 1,1, ..., m,n are pixels of the display, L1, ..., Lk are lenticular lens numbers, and the break lines indicate elementary lenses. [Diagram 3] A cross-section of a display with a vertical lenticular lens, the lenticular lens being separated at pixel rows by recessed stripes; a horizontal cross-section with a convexly curved surface, where RGB are the red, green, and blue subpixels of a pixel (by way of example), and the break lines are the lenticular lens. [Figure 4] FIG. 1 is a cross-section of a display with a vertical lenticular lens, the lenticular lens being separated at pixel rows by strip-shaped recesses, with no pixel magnification effect and an essentially flat surface, where R is the red sub-pixel of the pixel (by way of example) and the break lines are the lenticular lens. [Diagram 5] FIG. 2 is a plan view of an integral imaging display with multiple hemispherical element lenses, where 1,..,m are pixel rows, 1,...,n are pixel columns, and 1,1,...m,n are pixels of the display, and the broken lines are element lenses. [Figure 6] Plan view of a naked-eye 3D display with integral imaging-like optical elements arranged along columns, with each lens spanning, for example, two pixel columns, where 1,..,m are pixel rows and 1,..,n are pixel columns, and 1,1,...m,n are pixels of the display, and the broken lines are integral imaging-like pillow lenses. [Figure 7]FIG. 1 is a cross-sectional view of a naked-eye 3D display with integral imaging-like optical elements arranged along columns, with each lens extending to cover, for example, two pixel columns (illustrative example), and with a concave, convexly curved surface on the horizontal black matrix lines such that the pillow lenses are not continuous, i.e., broken, where RGB are the red, green, and blue subpixels of a pixel (illustrative example), and the break lines are the integral imaging-like pillow lenses. [Figure 8] FIG. 1 is a cross-sectional view of a naked-eye 3D display with integral imaging-like optical elements arranged along columns, with each lens extending to cover, for example, two pixel columns (illustrative example), and a vertical cross-section with recesses on the horizontal black matrix lines such that the pillow lenses are not continuous, i.e., broken, and have no pixel magnification effect, i.e., have a flat surface, where R is the red sub-pixel of the pixel, and the break lines are the integral imaging-like pillow lenses. [Figure 9] FIG. 14: Plan view of a naked-eye 3D display with optical elements similar to integral imaging, where the optical elements are shifted relative to each other by one line, with each lens spanning two pixel columns (by example), where 1..,m are pixel rows, 1..,n are pixel columns, and 1,1..,m,n are pixels of the display, and the broken lines are pillow-shaped lenses similar to integral imaging. [Figure 10] Cross-sectional view of a naked-eye 3D display with optical elements similar to integral imaging, where the arrows indicate the viewing directions of nine perspective projections of the viewing zone, each lens extends to cover two pixel columns (example), RGB are the red, green, and blue subpixels of a pixel (example), the broken lines are pillow-shaped lenses similar to integral imaging, and 1 is the viewing zone (example). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] In embodiment a) of the invention, the lenticular lenses are broken precisely in the horizontal gap area of ​​the display panel to prevent the magnification effect exactly at this location. Such breaking of the lens structure can occur during the production of the lens structure. For example, the material of the breaking line or surface can be heated, melted and washed away by laser exposure. This process is as precise as the manufacture of the lenses. An example of such an optical lens system is shown in Figures 3-4, which shows a cross section of a pixel row of a display panel.

[0027] Of course, it is preferred to select the line width such that such separation provides an optimal viewing quality for the viewer, even if the separation is somewhat smaller than the horizontal and vertical widths of the black gap regions. In particular, the lenticular lens has a configuration in which there is no pixel magnification effect in the vertical direction and / or the lens surface is essentially flat in the vertical direction.

[0028] The width (h) of the band-shaped recess measured horizontally from one end of the pixel to the other is preferably 20 to 120% of the spacing between adjacent pixel rows below it, and more preferably 80 to 105%.

[0029] The width (v) of the band-shaped recess measured vertically from one end of the pixel to the other is preferably 20 to 120% of the spacing between the pixel rows below, and more preferably 80 to 105%.

[0030] The band-like recess may be in the form of a groove, preferably a groove that is U-shaped with a rounded or angular cross section.

[0031] In a second embodiment (embodiment b)), instead of a lenticular lens, an optical lens system based on integral imaging technology is used (FIG. 5).

[0032] The pillow lenses have a configuration in which they have no pixel magnification effect in the vertical direction and / or the lens surface is essentially flat in the vertical direction, and in particular, they have a pixel magnification effect only in the horizontal direction, where each individual pillow lens covers a row of pixels and where the pixels are located on the display panel.

[0033] The vertical lens edges of the pillow lenses are arranged to vertically coincide with the pixel edges of the display panel, and in particular with the edges of each or every other pixel.

[0034] The vertical lens edges of the pillow lenses may be shifted from one horizontal pixel row to the next by one or more pixel columns, in particular up to four pixel columns.

[0035] A pillow-shaped lens can cover only one pixel, with I=1, and the viewing positions of adjacent lenses are adjacent, so that the diffraction angles of adjacent lenses are different from each other and the shapes of adjacent lenses match each other.

[0036] The optical lens system b) has a flat surface, in particular facing the display panel, and on its opposite outer surface comprises a number of pillow-shaped lenses arranged side by side.

[0037] Where the pillow lenses do not leave the horizontal and / or vertical gap areas between pixel rows intact, the pillow lenses form band-like recesses in their outer lens surface that are offset in parallel with respect to the viewer's position in front of the display and are arranged to at least partially cover the horizontal gap areas, the vertical gap areas, or the horizontal and vertical gap areas between pixels.

[0038] In the embodiment of Figure 10, each lens covers a number of horizontally adjacent pixels (I > 1). The magnifying lens covers many of these adjacent pixels and is suitable for displaying images and videos captured by a stereo camera with only two or more lenses.

[0039] Thus, there is image and video content that has been recorded for decades and can be easily displayed, which is not possible with classical integral imaging displays.

[0040] The pillow lenses of such an optical lens system horizontally cover only the pixels of the display and do not cover the horizontal gap areas between the pixel rows. Figure 6 shows a plan view of such a display.

[0041] The black gap areas between the pixel rows are not magnified. This significantly improves the readability and visibility of small objects. Lens structures that magnify pixels horizontally exhibit a horizontal "walk-around effect" identical to naked-eye 3D with lenticular lenses. However, according to the preferred embodiment, the back of foreground objects does not appear vertically, as this was not recorded due to the horizontal position of the stereo camera's objective lens, and therefore such lenses do not require a pixel-magnification effect in the vertical direction. The additional vertical (length) degree of freedom has been removed for compatibility with existing stereo cameras.

[0042] When the individual lenses of such an integral imaging-like optical lens system are displaced from each other line by line based on a tilted lenticular lens structure (see FIG. 9), one or more viewers at different positions in front of the display can simultaneously have a good spatial visual impression. Unlike a tilted lenticular lens system, the edges of each individual lens are aligned horizontally and vertically. The horizontal effect is due to the effective disappearance of the horizontal black gap areas between the pixel rows.

[0043] Vertically, a lens always completely covers a pixel from the top to the bottom of the pixel.

[0044] This is not the case with tilted lenticular lenses, which give rise to so-called Moiré effects, which must be compensated for with great effort. With optical lens systems similar to integral imaging, this is not necessary.

[0045] In the above, it has been described that each lens I covers multiple adjacent pixels horizontally of the display. In the case of a lenticular lens system, the pixels covered by each lens I can be 3-4 pixels or 9 or 12 RGB sub-pixels.

[0046] However, this is not necessarily the case: if the lens is designed to cover just 3 RGB subpixels in an RGB display, or just 4 subpixels in an RGBW or RGBY display, then I=1 may be chosen.

[0047] However, in this case, the diffraction angles of adjacent lenses must match each other and the viewing positions of adjacent lenses must also be adjacent to produce a uniform viewing zone in front of the display. This relationship is shown in Figure 10, which has 9 perspective projections.

[0048] Such a structure also avoids the appearance of vertical gap regions between pixel columns.

[0049] Such optical lens systems are compatible with all display technologies such as OLED, LCD, quantum dot, etc. and can be used for any resolution and display size. Of course, the size and structure of the lens must be tailored to the display.

[0050] The effect of the black gap area between pixels being magnified is particularly well known in the projection art, where the black gap area may be magnified by the projector, an effect known as the "screen door" effect.

[0051] The ε value is especially important in the present invention because the gap areas between pixels are not always uniformly linear but may be octagonal or other structures of pixels and sub-pixels (e.g. Pentile displays), in which case the lens or black stripes of the optical element will show the balancing effect.

[0052] Unlike naked-eye 3D displays based on tilted lenticular lenses, embodiments of the present invention have vertical lens edges that are not tilted and coincide with the pixel edges of the display panel, which further improves image quality and readability of characters, etc.

[0053] Particular attention must be paid to the precise positioning of the new and improved lens system: the strip recesses must be placed as precisely as possible over the gap areas between the pixel structures used.

[0054] Precise mechanical positioning directly above the display panel is standard technology in display production and is already used for positioning electronic products.

[0055] In addition, IH Naske's "Method and device for pseudo-holographic image synthesis", EP2027728A1, can easily realize super multi-view technology.

[0056] In essence, the optical lens system described above can be said to exist somewhere between lenticular lens technology and integral imaging technology.

Claims

1. 1. A naked-eye 3D display for improving naked-eye 3D viewing quality, comprising a display panel in which a plurality of pixels representing the content of a stereoscopic image to be displayed in two or more perspective projections are separated from each other by gap regions, and an optical lens system in one of two configurations arranged towards a viewer in front of the display panel, a) the optical lens system has a flat surface covering the display panel and an opposite surface comprising a plurality of lenticular lenses arranged side by side in a horizontal direction, the lenticular lenses having a convexly curved surface on an outer lens surface, each lenticular lens having a strip-shaped recess on its outer lens surface, the recesses being offset in parallel to each other with respect to a viewer's position in front of the display, and in a first configuration at least partially covering the vertical gap areas between pixels; or b) a second configuration, wherein the optical lens system comprises a plurality of pillow lenses that are horizontally convexly curved and arranged side-by-side in a layer, each of the lenses covering at least 2 to 16 horizontally adjacent pixels, with horizontal gap areas between pixel rows being preserved intact by the pillow lenses; Each of the band-shaped recesses is in the shape of a groove having a rounded U-shaped cross section, or in the shape of a groove having a flat bottom surface and two flat side surfaces that are continuous with and perpendicular to the bottom surface, A naked-eye 3D display, characterized in that the width (h) of the strip-shaped recess, measured horizontally from one end of a pixel to the other, is 20 to 120% of the spacing between adjacent pixel rows below it.

2. the optical lens system is in the first configuration; 2. The naked-eye 3D display of claim 1, wherein the lenticular lens has no pixel magnification effect in the vertical direction and the lens surface is essentially flat in the vertical direction.

3. 3. The naked-eye 3D display of claim 1 or 2, characterized in that the optical lens system has a flat surface facing the display panel and the opposite outer surface has a horizontally curved lenticular lens structure.

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