Lenticular lens for a naked-eye stereoscopic display device with reduced moiré

Abstract

The present invention relates to a lenticular device having a profile surface extending in the x-direction and the y-direction and having a profile in the z-direction perpendicular to the profile surface. The profile surface defines that an array of elongated lenticular elements has lenticular surfaces that intersect each other along an intersection line. At least one intersection line in the lenticular device is a curved intersection line including one or more curved segments curved in the x-direction and / or the z-direction. A lenticular lens having such a curve reduces a moiré pattern when disposed on an array of display pixel elements in a naked-eye stereoscopic display device. Accordingly, the present invention also relates to a naked-eye stereoscopic display device including such a lenticular device and an array of display pixel elements.

Description

Technical Field

[0001] The present invention relates to a lenticular device, a method of preparing such a lenticular device, a lens assembly including such a lenticular device, a naked-eye stereoscopic display device including such a lenticular device or such a lens assembly, and a method of reducing moiré patterns in a naked-eye stereoscopic display device.

Background Art

[0002] Naked-eye stereoscopic displays are playing an increasingly important role in virtual reality and augmented reality applications. One of the most prominent features of a naked-eye stereoscopic display is the ability to enable a viewer to perceive the depth of the images it displays (stereoscopic vision) without the need for glasses or other dedicated eyewear. Furthermore, this principle also functions when the viewer moves relative to the naked-eye stereoscopic display.

[0003] The key to this technology is the presence of a screen including a lenticular lens or a parallax barrier disposed in front of an array of pixels. This enables the pixel output (i.e., light) to be directed in a specific spatial direction, which enables selective illumination of only one of a pair of eyes. By precisely controlling the pixels, the screen can direct the left-eye image to the viewer's left eye and the right-eye image to the viewer's right eye simultaneously. The resulting stereoscopic image can provide the viewer with a sense of depth perception, and elements within the image can appear in front of the display or further away from the display (behind the display).

[0004] However, many conventional autostereoscopic displays have the problem of showing moiré patterns. Both lenticular lenses and parallax barriers are regular structures each composed of semi-cylindrical microlenses (lenticulars) or elongated slits arranged parallel to each other. The superposition of such a regular structure and the (similarly regular) array of pixels may cause viewers to perceive moiré patterns, which are often disturbing to viewers. This is not only to impair the displayed image, but also, for example, to make the moiré pattern visible on the screen itself as in the case of reflection. This stops the illusion of a "floating" 3D image in the environment in front of or behind the screen.

[0005] To date, many efforts have been made to reduce or even completely cancel moiré patterns in this type of display. For example, it is possible to identify the pixels that contribute the most to moiré and then modify their pixel outputs in a specific way. However, this has undesirable side effects such as a decrease in resolution and / or a decrease in display intensity. It also requires valuable processor capacity. Other solutions relate to the application of specific pixel shapes and pixel arrangements in combination with specific lenticular tilt angles. However, this limits the design opportunities for autostereoscopic display devices and makes the manufacturing process more critical as a tilt deviation of a fraction of a degree can already cause moiré. SUMMARY OF THE INVENTION

[0006] Accordingly, an object of the present invention is to find a solution to the occurrence of moiré patterns that does not exhibit one or more of the above-mentioned side effects. Another object is to provide a solution that is not more complex than the solutions known in the art. More generally, an object of the present invention is to improve the viewing experience of viewers of autostereoscopic displays.

[0007] It has been found that one or more of these objects can be achieved by applying specific modifications to the lenticular lenses of autostereoscopic displays.

[0008] Thus, the present invention is a lenticular device (1) having a profile surface (2), - extending in the -x direction and the y direction perpendicular to the x direction, - having a profile in the z direction perpendicular to the profile surface (2), The profile surface (2) is an elongated lenticular element (3), - having a lenticular length in the y direction, - arranged parallel to each other, - having lenticular surfaces intersecting each other along the intersection line (4), defining an array of lenticular elements (3), At least one intersection line (4) is a curved intersection line, relates to a lenticular device (1).

[0009] The lenticular device (1) may be a lenticular lens or a mold for preparing a lenticular lens.

[0010] The present invention further relates to a naked-eye stereoscopic display device having an array (9) of display pixel elements and the lenticular lens described above.

[0011] The present invention further relates to a method for manufacturing a lenticular device having a profile surface defining an array of elongated lenticular elements, - a plate having a surface that can be engraved, ○ extending in the x direction and the y direction perpendicular to the x direction, ○ having a z direction perpendicular to the surface that can be engraved providing a plate, - providing a device including a chisel having a shape corresponding in negative relief to the shape of the cross-section of the elongated lenticular element in the lenticular device manufactured by the method, -Forming a profile surface by sequentially engraving a plurality of parallel and elongated lenticular elements on a plate using a chisel by moving the chisel in the y-direction of the plate, wherein the lenticular elements formed on the plate intersect each other at the intersection lines, comprising while moving the chisel in the z-direction, the chisel is moved in the x-direction and / or the z-direction so that a curved intersection line is formed, relating to a method.

[0012] The present invention further relates to a method of manufacturing a naked-eye stereoscopic display device, including the use of a lenticular lens as described above or the use of an array of display pixel elements and a lens assembly including a lenticular lens as described above.

[0013] The present invention further relates to a method of reducing moire patterns in a naked-eye stereoscopic display device, including the use of a lenticular lens as described above, and in particular, a method by lining up an array of display pixel elements with the lenticular lens as described above.

Brief Description of the Drawings

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Best Mode for Carrying Out the Invention

[0015] The drawings do not limit the present invention to the specific embodiments disclosed therein and described herein. The elements in the figures are shown for simplicity and clarity and are not necessarily drawn to scale; instead, emphasis is placed on clearly showing the principles of the present invention. For example, the dimensions of the lenticular elements and the degree of curvature of the intersection lines between them cannot be derived from the figures. The shape and arrangement of the display pixel elements in the figures are not intended to reflect reality. Further, their dimensions relative to the dimensions of the lenticular elements also cannot be derived from the figures.

[0016] Furthermore, terms such as "first," "second," etc. in this specification and the claims, if any, are generally used to distinguish similar elements or items and are not necessarily used to describe a sequential or chronological order.

[0017] In the context of the present invention, the term "viewer" means a person who consumes, specifically, can view the content presented by the autostereoscopic display device. Throughout this text, references to the viewer are made by male words such as "he," "him," or "his." This is for the purpose of clarity and brevity only, and it is understood that female words such as "she" and "her" are equally applicable.

[0018] In the context of the present invention, the term "moiré" means the viewer's perception of a pattern ("moiré pattern") that appears by the superposition of two actual patterns that are slightly displaced, slightly rotated, and / or have slightly different pitches. Also, moiré can occur when the pitch of one pattern is close to (but not exactly) an integer (such as 2, 3, 4, etc.) multiple of the pitch of the other pattern. The moiré that is reduced or overcome in the present invention typically relates to the superposition of the pattern of the pixel array and the pattern of the lenticular array.

[0019] Several terms introduced below, such as "lenticular length", "V-shaped valley", "sharp ridge line", and "intersection line", are presented as extending in the "y direction". However, in certain embodiments of the present invention, namely, embodiments where the curved intersection line includes one or more curved segments curved in the x direction and / or the z direction, it will be understood that these terms also have components in the x direction and / or the z direction (although very small components). However, for the sake of clarity, this is not always stated. Ultimately, when averaged over the entire lenticular device, the relevant terms extend only in the y direction of the lenticular device of the present invention.

[0020] The lenticular device according to the present invention is an object including a profile surface, that is, a surface having surface relief or profiling.

[0021] For the purpose of clearly explaining the present invention, the x direction, y direction, and z direction are defined with respect to the lenticular device according to the present invention. Here, the y direction is a direction perpendicular to the x direction, and the z direction is a direction perpendicular to the plane ((x, y) plane) defined by the x direction and the y direction. The surface of the lenticular device extends in the x direction and the y direction regardless of the surface relief extending in the z direction.

[0022] The profile surface has an elongated shape (and length) in the y direction and is formed as an array of lenticular elements that define the lenticular length in the y direction. The lenticular elements are arranged side by side in the x direction and extend in the y direction parallel to each other. When lined up on an array of display pixel elements, such an array of lenticular elements is a known means for directing the outputs from different pixel elements in different directions from each other so that a stereoscopic image can be displayed to (perceived as three-dimensional by) the viewer.

[0023] In this specification, the term "arranged" is used to describe only a particular appearance or aspect, rather than a configuration of separate parts, since the lenticular elements are not arranged as separate objects. The lenticular device according to the present invention consists, in principle, of one single part, and as a result, all the different lenticular elements are parts of the same piece of material. Optionally, the lenticular lens comprises a coating and / or a casing. The lenticular elements in the lenticular device according to the present invention have either a convex (circular) shape or a concave (hollow) shape, which means that the lenticular device typically contains only one of these types of lenticular elements.

[0024] The parallel arrangement is understood to mean an arrangement in which adjacent lenticular elements "touch" each other in the sense that there is in principle no intervening surface between two adjacent lenticular elements that are not of lenticular shape, such as a flat surface extending in the x- and y-directions (when the lenticular device is prepared by engraving the lenticular elements on the flat surface of a plate, the flat intervening surface between two adjacent lenticular elements corresponds to the surface that has not been treated by engraving).

[0025] The boundary between two adjacent lenticular elements is indicated by a sharp change in the slope of the profile surface in a cross-sectional plane defined by the x- and z-directions (i.e., the (x,z) plane). When the lenticular element has a convex shape, the boundary between two lenticular elements can be regarded as a V-shaped valley extending in the y-direction of the profile surface, and when the lenticular element has a concave shape, the boundary between two lenticular elements can be regarded as a sharp ridge extending in the y-direction on the profile surface.

[0026] The boundary between two adjacent lenticular elements is formed by a line that coincides with either the lowest point of a V-shaped valley (i.e., the lowest in the z-direction) or the highest point of a sharp ridge line (i.e., the highest in the z-direction). This line is actually the intersection of the lenticular surfaces of two adjacent lenticular elements. Therefore, for the purposes of the present invention, this line is denoted by the term "intersection line".

[0027] Figure 1 schematically shows a lenticular device (1) according to the present invention. It includes a profile surface (2) that defines an array of elongated lenticular elements (3). Each of these has a lenticular surface that intersects the lenticular surfaces of adjacent lenticular elements (3) along an intersection line (4). For clarity, Figure 1 does not represent that one or more intersection lines (4) are curved as required by the present invention. However, the curved intersection lines (4) are clearly shown in the remaining Figures 2 - 8.

[0028] In addition to the lenticular length, the lenticular element also has a lenticular width. This dimension is defined as the distance between two intersection lines on either side of the lenticular element, measured in the x-direction along anywhere in the y-direction. However, the distance is measured not via a line directly connecting the two intersection lines, but via a line projected onto both intersection lines from the z-direction. This is to account for the deviation that can occur when the line directly connecting the two intersection lines has a z-direction component (as can be the case for the lenticular lens according to the present invention, which will be described in more detail below).

[0029] The definition of the lenticular width (7) is shown in Figure 7, which shows a cross-sectional view of the lenticular device (1) of the present invention in the (x,z) plane. There are valleys (5) on either side of any lenticular element (3) that define an intersection line (not shown in the figure) running perpendicular to the plane of the figure. The valleys (5) on either side of the lenticular element (3) have different positions in the z-direction, and the difference is indicated by two horizontal dotted lines (6). The distance between the two valleys projected in the z-direction forms the lenticular width (7).

[0030] Furthermore, throughout this specification, it can be said that elongated items that are not perfectly straight are arranged parallel to each other. Thus, the term "parallel" means that the items are arranged facing each other side by side with their longest dimensions. In this way, their arrangement is considered parallel.

[0031] The lenticular elements in prior art lenticular devices are all straight and have the same shape. However, this does not apply to the lenticular device of the present invention in which the lenticular elements are curved in the x direction and / or the z direction. A specific curvature may be applied to all the lenticular elements (as a result, they are still the same). Alternatively, different lenticular elements may be subject to different curvatures (so that not all lenticular elements are the same).

[0032] When the lenticular element is curved, one or both of the two intersection lines on both sides of the lenticular element have curvature. Thus, the present invention is characterized in that the lenticular lens includes at least one intersection line that is a curved intersection line. The curvature may be in the x direction and / or the z direction.

[0033] The curved intersection line is a line having at least one curved segment. The term "curved" means that the line is not straight but curved. Such bending is usually a smooth change in the direction of the line. However, it may be a sharp change, such as an angle or a zigzag.

[0034] The curved intersection line may be curved along its entire length or along a part of its entire length. In the latter case, the intersection line includes, for example, one or more curved segments and one or more straight segments.

[0035] In the context of the present invention, a segment of an intersection line can include a specific portion of the intersection line or the entire intersection line. Further, a curved segment of the intersection line can be any segment that does not include a straight portion. The curved segment can also be another adjacent curved segment that does not have a straight segment between the curved segments.

[0036] Typically, a curved intersection line is a line that includes one or more curved segments. For example, one or more curved segments are curved in the x-direction, one or more curved segments are curved in the z-direction, or one or more curved segments are curved in both the x-direction and the z-direction. Also, there may be segments with different curvatures in a single lenticular element, for example, at least one segment curved in the x-direction and at least one segment curved in the z-direction.

[0037] Figures 2 and 3 are perspective views of first and second lenticular devices (1) according to the present invention. They show two adjacent lenticular elements (3) sharing an intersection line (4). In Figure 2, the intersection line (4) has a curvature only in the x-direction. In Figure 3, the intersection line (4) has a curvature only in the z-direction.

[0038] Figures 4 to 6 are schematic top views of three different embodiments according to the present invention. They show a lenticular element (3) and a curved intersection line (4), and the curved intersection line (4) is curved in the x-direction. In these figures, emphasis is placed on the different shapes and relative arrangements of the intersection line (4).

[0039] In Figure 4, the curved intersection lines (4) are different in that they have different curvatures. The lenticular element (3) in the middle portion of the lenticular device (1) has a large displacement in the x-direction compared to the upper and lower lenticular elements. The displacement of the lenticular element (3) in the middle portion (having the largest displacement) exceeds several times the maximum lenticular width.

[0040] In FIG. 5, all the curved intersection lines (4) have the same curvature but different "phases", and thus, in the lenticular element (3), there are variations in their lenticular widths along the y direction.

[0041] In FIG. 6, all the curved intersection lines (4) are the same and have the same "phase", so the lenticular element (3) has a constant lenticular width along the y direction.

[0042] For the purpose of the present invention, the degree of curvature of the intersection line in the x direction is explained by the variation of the intersection line in the x direction, which is the distance range in the x direction where the intersection line has curvature. These variations are defined by associating them with the average lenticular width. For this purpose, the average lenticular width is multiplied by a coefficient within a specific range. In the lenticular device of the present invention, the curved intersection line can exhibit variations in the x direction that are up to 1.0 times the average lenticular width, and the average lenticular width is defined as the length of the x - direction array divided by the number of lenticular elements present in the x direction.

[0043] The variation in the x direction may also be greater than 1.0 times the average lenticular width, for example, up to 2.0 times, 5.0 times, or 10.0 times the average lenticular width (see, for example, FIG. 4). Such large variations require that adjacent intersection lines undergo similar variations in the x direction. Otherwise, the lenticular elements will either be too small or too far apart to define the intersection line. This is explained in the following paragraphs.

[0044] The variation of the intersection line in the x - direction is usually acceptable only if the separation of the two intersection lines on both sides of the lenticular element is not excessively reduced. This is because it would make the lenticular element too narrow and the viewing field of the lenticular element would be too small to provide a good viewing experience. Therefore, a separation of 0.60 times the average lenticular width is usually taken as the minimum value. Since the span in the x - direction that can be achieved by a lenticular element with a given shape cannot be exceeded, there is also an upper limit to the separation of the two intersection lines. Usually, a value of 1.40 times the average lenticular width is taken as the maximum.

[0045] Therefore, in the lenticular device according to the present invention, two adjacent intersection lines are usually separated by a variable distance within the range of 0.60 to 1.40 times the average lenticular width measured along the x - direction, and the average lenticular width is defined as the length of the x - direction array divided by the number of lenticular elements present in the x - direction.

[0046] The variable distance between the two intersection lines may also vary within the range of 0.65 to 1.35 times the average lenticular width, within the range of 0.70 to 1.30 times the average lenticular width, within the range of 0.75 to 1.25 times the average lenticular width, within the range of 0.80 to 1.20 times the average lenticular width, within the range of 0.85 to 1.15 times the average lenticular width, within the range of 0.90 to 1.10 times the average lenticular width, within the range of 0.93 to 1.07 times the average lenticular width, or within the range of 0.95 to 1.05 times the average lenticular width.

[0047] For the purposes of the present invention, the degree of curvature of the intersection line in the z - direction is explained by the variation of the intersection line in the z - direction, which is the distance range in the z - direction in which the intersection line has its curvature. These values are also defined by associating them with the average lenticular width. For this purpose, the average lenticular width is multiplied by a coefficient within a specific range. In the lenticular device of the present invention, the curved intersection line can exhibit a variation in the z - direction that is up to 1.0 times the average lenticular width, and the average lenticular width is defined as the length of the x - direction array divided by the number of lenticular elements present in the x - direction.

[0048] The variation in the z - direction may also be greater than 1.0 times the average lenticular width, for example, up to 2.0 times, up to 3.0 times, or up to 5 times the average lenticular width. Such large variations require that adjacent intersection lines undergo similar variations in the z - direction. Otherwise, one lenticular element may become too high compared to another adjacent lenticular element.

[0049] Some or all of the curved intersection lines may have essentially the same shape. When two of such intersection lines are on both sides of a lenticular element, the lenticular element may have a constant lenticular width (see, for example, FIG. 6).

[0050] Thus, in the lenticular device of the present invention, there may be at least one lenticular element having a lenticular width that is substantially constant over its lenticular length. However, the number of such lenticular elements is usually larger. It is preferably defined as a percentage of the total number of lenticular elements that are part of the lenticular device of the present invention. For example, the percentage of such lenticular elements is at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, or at least 95%.

[0051] Generally, in the lenticular device according to the present invention, at least 50% of the intersection lines are curved intersection lines. The percentage may also be at least 10%, at least 20%, at least 30%, at least 40%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%. It is also possible that all the intersection lines are curved intersection lines.

[0052] In the lenticular device according to the present invention, a plurality of (x, z) planes may be defined perpendicular to the lenticular length of the lenticular element. The cross - sectional shape of the lenticular element in each of the (x, z) planes may then have an aspect ratio x:z. z is in the range of 6:1 to 3:1, particularly in the range of 5:1 to 4:1.

[0053] In a conventional lenticular lens, a lenticular element has a focal length that can focus light along a focal line extending parallel to the lenticular length (i.e., in the y direction). Such a focal line is a collection of foci that together form the focal line.

[0054] The same also applies to the lenticular device of the present invention when the lenticular device is a lenticular lens. In such a case, it is composed of a transparent material that can function as a lenticular lens.

[0055] However, the lenticular device of the present invention does not necessarily have to be a lenticular lens. It may also be an opaque material. In this way, the lenticular device of the present invention can, for example, act as a lenticular mold for the production of a lenticular lens by bringing a profile surface into contact with a (usually fluid) curable resin and subsequently curing the curable resin to obtain a solid and transparent lens material. Such a lenticular mold, although it usually cannot function as a lens (because it is an opaque material), still falls within the scope of the present invention because it has the same lenticular surface as a true lenticular lens (corresponding only in negative relief). Such a lenticular device of the present invention can in principle be made from any material suitable for acting as a mold in a molding process.

[0056] Therefore, in one embodiment, the lenticular device of the present invention is a lenticular lens, for example, a device that can refract light when light passes through the lens. In another embodiment, the lenticular device of the present invention is a mold for preparing a lenticular lens.

[0057] Thus, the lenticular element of the device of the present invention may not function as a lenticular lens in some examples. In practice, however, it has the same profile as a true lenticular lens, i.e., when the device is an opaque material. In such a case, the shape of the lenticular element can be regarded as identical to the shape of a true lenticular lens.

[0058] Thus, in particular, when the lenticular device of the present invention is an opaque material, the lenticular element of such a lenticular device can be considered to have a cross-sectional shape in the (x,z) plane corresponding to the cross-sectional shape of a lenticular lens having a specific focal length (thus, when the mold is made of lens material, the lenticular element will have a specific focal length).

[0059] In a particular embodiment, the lenticular element may be considered to have a cross-sectional shape in any (x,z) plane corresponding to the cross-sectional shape of a lenticular lens having a constant focal length in the (x,z) plane. This means that when the lenticular device of the present invention is a lenticular lens, the focal length of the lenticular element is constant over the entire length of each lenticular element (i.e., in the y direction), and when the lenticular device of the present invention is a lenticular mold, the focal length of the lenticular element of the lenticular lens prepared from the mold is constant over the entire length of each lenticular element. It is understood here that when the lenticular lens is a concave lenticular lens, the focus must be identified as a virtual focus. Correspondingly, such a lenticular lens has a constant virtual focus over the entire length of each lenticular element.

[0060] It is understood that lenticular elements, for example, may have a shape that produces an accurate focus only by approximation, since their convex or concave shapes are not perfect parabolas. For example, a circular shape can be a good approximation, especially when only a relatively small angle of the circle is used. A lenticular device having any such lenticular element (e.g., non-parabolic) that can provide a useful imaging when applied to a naked-eye stereoscopic display device is included in the present invention.

[0061] The present invention further relates to a lens assembly (8) including an array (9) of display pixel elements and the above-described lenticular device (1), where the lenticular device (1) is a lenticular lens. The array is typically lined with a lenticular lens such that the lenticular lens covers at least a portion of the array.

[0062] Such a lens assembly is schematically shown in FIG. 8. Due to the curve of the intersection line, the regular ordering of the lenticular elements is "broken". As a result, the display pixel elements do not find an ordered counterpart within the lenticular elements that can produce a moiré pattern. As a result, the moiré shown by the naked-eye stereoscopic display device having the lens assembly of the present invention is less than that of known naked-eye stereoscopic display devices.

[0063] The present invention further relates to a naked-eye stereoscopic display device including a lens assembly as described above.

[0064] The present invention further relates to a naked-eye stereoscopic display device including an array (9) of display pixel elements and a lenticular device (1) as described above, where the lenticular device (1) is a lenticular lens. The array is typically lined with a lenticular lens such that the lenticular lens covers at least a portion of the array.

[0065] The present invention further relates to a method of manufacturing a lenticular device having a profile surface that defines an array of elongated lenticular elements, - a plate having a surface that can be engraved, ○extending in the x direction and the y direction perpendicular to the x direction, ○having a z direction perpendicular to the sculptable surface providing a plate, - providing an apparatus including a chisel having a shape corresponding in negative relief to the shape of a cross-section of an elongated lenticular element within a lenticular device manufactured in that way, - subsequently, by moving the chisel in the y direction of the plate, using the chisel to engrave a plurality of parallel elongated lenticular elements in the plate to form a profile surface, wherein the lenticular elements formed in the plate intersect each other at the intersection lines, including forming, Regarding a method, while moving the chisel in the z direction, the chisel is moved in the x direction and / or the z direction so that a curved intersection line is formed.

[0066] In this method, a single lenticular element (or a group of several lenticular elements, for example, a group of 2, 3 or 4 lenticular elements) is manufactured by their sequential engraving. In this way, each lenticular element can be prepared in a different way from adjacent lenticular elements. Thereby, any lenticular device as described above can be obtained.

[0067] If it is desired that the curved intersection line of the lenticular device of the present invention includes one or more curved segments that are curved only in the z direction (not curved in the x direction), two lenticular elements sharing such an intersection line need to be engraved by moving the chisel in exactly the same way for each lenticular element, that is, by moving it in the z direction in the same way without moving it laterally in the x direction (see, for example, Figure 3). Eventually, if two adjacent lenticular elements are engraved at different depths on the surface, this results in an intersection line between the two lenticular elements showing variations in the x direction.

[0068] If the curved intersection line of the lenticular device of the present invention includes one or more curved segments that are curved only in the x direction (not curved in the z direction), two lenticular elements sharing such an intersection line are engraved by moving the chisel in exactly the same way for each lenticular element, that is, by moving it in the same lateral direction in the x direction without moving it in the z direction (see, for example, FIG. 2). Eventually, if two adjacent lenticular elements are engraved with different lateral movements, this results in an intersection line between both lenticular elements indicating a variation in the z direction.

[0069] After the method of the present invention, an optional shaping step follows, where the profile surface is brought into contact with a fluid-curable resin, and subsequently the curable resin is cured to obtain a lenticular lens. Alternatively, in the shaping step, the profile surface is brought into contact with a fluid or moldable (e.g., thermoplastic) material at a high temperature, and subsequently the material is cooled to obtain a lenticular lens.

[0070] In one embodiment, after the method of the present invention, it is followed by manufacturing a naked-eye stereoscopic display device by using the manufactured lenticular device, where the lenticular device is a lenticular lens.

[0071] In one embodiment, after the method of the present invention, it is followed by preparing a lens assembly including an array of display pixel elements and a lenticular device as described above, where the lenticular device is a lenticular lens. This typically includes lining the array with the lenticular lens such that the lenticular lens covers at least a part of the array.

[0072] Optionally, after the method for preparing the lenticular lens assembly, it is followed by manufacturing a naked-eye stereoscopic display device using the prepared lenticular lens assembly.

[0073] The present invention further relates to a method for reducing moiré patterns in a naked-eye stereoscopic display device, including the use of a lenticular lens as described above. The method may particularly include lining up an array of display pixel elements with a lenticular lens as described above.

Claims

1. A lenticular device (1) having a profile surface (2), - extending in the -x direction and the y direction perpendicular to the x direction, - having a profile in the z direction perpendicular to the profile surface (2), The profile surface (2) is an elongated lenticular element (3), - having a lenticular length in the y direction, - arranged parallel to each other, - having lenticular surfaces intersecting each other along an intersection line (4), defining an array of lenticular elements (3), A lenticular device (1), wherein at least one intersection line (4) is a curved intersection line.

2. The lenticular device (1) according to claim 1, wherein the curved intersection line (4) includes one or more curved segments curved in the x direction.

3. The lenticular device (1) according to claim 1 or 2, wherein the curved intersection line (4) includes one or more curved segments curved in the z direction.

4. The lenticular device (1) according to any one of claims 1 to 3, wherein the curved intersection line (4) includes one or more curved segments curved in the x direction and the z direction.

5. The lenticular device (1) according to any one of claims 1 to 4, wherein the curved intersection line (4) includes one or more curved segments curved in the x direction, and the curved segments have a variation in the x direction that is at most 1.0 times the average lenticular width, and the average lenticular width is defined as the length of the array in the x direction divided by the number of lenticular elements present in the x direction.

6. The lenticular device (1) according to any one of claims 1 to 5, wherein the curved intersection line (4) includes one or more curved segments curved in the z direction, and the curved segments have a variation in the z direction that is at most 1.0 times the average lenticular width, and the average lenticular width is defined as the length of the array in the x direction divided by the number of lenticular elements present in the x direction.

7. Two adjacent intersection lines (4) are separated by a variable distance within a range of 0.60 to 1.40 times, particularly within a range of 0.80 to 1.20 times, of the average lenticular width measured along the x direction, and the average lenticular width is defined as the length of the array in the x direction divided by the number of lenticular elements present in the x direction, the lenticular device (1) according to any one of claims 1 to 6.

8. The lenticular device (1) includes at least one lenticular element (3) having a lenticular width that is substantially constant over its lenticular length, the lenticular width being defined as the projection distance in the x direction between two intersection lines on both sides of the lenticular element, and the projection distance is projected in the z direction, the lenticular device (1) according to any one of claims 1 to 6.

9. - A plurality of (x, z) planes are defined perpendicular to the lenticular length of the lenticular element, - The cross-sectional shape of the lenticular element in each of the (x, z) planes has an aspect ratio x:z in the range of 6:1 to 3:1, particularly in the range of 5:1 to 4:1, The lenticular device (1) according to any one of claims 1 to 8.

10. - A plurality of (x,, z) planes are defined perpendicular to the lenticular length of the lenticular element, - The cross-sectional shape of the lenticular element in the (x, z) plane corresponds to the cross-sectional shape of a lenticular lens having a focal length that is constant along the lenticular length, The lenticular device (1) according to any one of claims 1 to 9.

11. At least 50%, particularly at least 80%, of the intersection lines (4) are curved intersection lines, the lenticular device (1) according to any one of claims 1 to 10.

12. The lenticular device (1) is a lenticular lens, the lenticular device (1) according to any one of claims 1 to 11.

13. The lenticular device (1) is a mold for preparing a lenticular lens, the lenticular device (1) according to any one of claims 1 to 11.

14. A lens assembly (8) for use in a naked-eye stereoscopic display device, comprising an array (9) of display pixel elements and the lenticular device (1) according to claim 12.

15. A naked-eye stereoscopic display device comprising the lenticular device (1) according to claim 12, in particular the lens assembly (8) according to claim 14.

16. A method of manufacturing a lenticular device having a profile surface defining an array of elongated lenticular elements, comprising: - providing a plate having a surface that can be engraved, ○ extending in the x direction and the y direction perpendicular to the x direction, ○ having a z direction perpendicular to the surface that can be engraved providing a plate; - providing a device including a chisel having a shape corresponding in negative relief to the shape of a cross-section of an elongated lenticular element within the lenticular device; - subsequently, moving the chisel in the y direction of the plate to engrave a plurality of parallel elongated lenticular elements on the plate using the chisel to form the profile surface, wherein the lenticular elements formed on the plate intersect each other at the intersection lines; including while moving the chisel in the y direction, the chisel is also moved in the x direction and / or the z direction so that a curved intersection line is formed.

17. The method according to claim 16, followed by preparing a lens assembly including an array of display pixel elements and the lenticular device according to claim 12.

18. The method according to claim 16 or 17, followed by manufacturing a naked-eye stereoscopic display device.

19. A method of manufacturing a naked-eye stereoscopic display device including using the lenticular device according to claim 12 or the lens assembly according to claim 14.

20. A method of reducing moiré patterns in a naked-eye stereoscopic display device, including using the lenticular device according to claim 12, in particular by lining an array of display pixel elements with the lenticular device according to claim 12.

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