MXPA99001615A - Substrate producing three-dimensional images - Google Patents

Abstract

A substrate is arranged to present a three-dimensional optical image to a viewer, the substrate being formed with a plurality of stereo pairs of grooves or ridges, each such pair of elements providing the viewer with an image of a point at a predetermined distance from the plane of the substrate:the plurality of point images forms the three-dimensional optical image. For example, a pair of linear grooves (14, 16), oriented as shown, reflect incident light (B) into the respective eyes of a viewer, to give the image of a point (P) at a distance (r) behind the substrate surface.

Description

SUBSTRATE THAT PRODUCES THIRD-DIMENSION IMAGES FIELD OF THE INVENTION The present invention relates to substrates that provide one or more three-dimensional images.

BACKGROUND OF THE INVENTION There are many applications where three-dimensional optical images are required or where these are desirable. In the past several devices have been proposed, these comprise a two-dimensional substrate arranged to provide a three-dimensional optical image to an observer. We have currently invented a substrate arranged to present a three-dimensional image to an observer and which provides several advantages. In accordance with the present invention, a substrate is provided which is arranged to present one or more three-dimensional optical images to an observer, the substrate is formed by a plurality of stereo pairs of elements, each stereo pair of elements provides the observer with an image of a point at a predetermined distance from the plane of the substrate, the plurality of these point images form the three-dimensional optical images.

P1136 / 99MX The two elements of each stereo pair provide light to the respective eyes of the observer when he observes the substrate from a particular position or a range of positions. The light can be provided to the observer either by reflection from the elements of the stereo pair or by the light that these elements refract and transmit through the substrate (which is made of a transparent or semi-transparent material). The two elements of each stereo pair may comprise grooves or ribs formed in or on the surface of the substrate: they may comprise reflective impressions provided in a document, particularly a document with value (for example a banknote). Preferably each stereo pair of elements comprises two short linear elements (particularly grooves or ribs), whose relative orientations determine the distance of the corresponding point image from the plane of the substrate. For each point image, a plurality of stereo pairs are preferably provided, so that the same point can be observed from different angles. The stereo pairs for each spot image can also be placed on a common straight line. Different stereo pairs can be moved from that line to ensure that the spot image remains P1136 / 99MX stationary as the observer changes his angle of observation, or alternatively so that the point image moves: in the latter case, an image of an object in motion can be created. . However, it is not necessary for successive stereo pairs of a specific point image to be placed on a common line. In fact, the pairs can move towards desired positions separated from the common line, for example they can be placed along any curved line, if they are placed in an appropriate way and are oriented towards each other. In this way, the set of stereo pairs for different image points can be kept separate and thus avoid intersection or any type of interference with each other. If the stereo pairs are placed in the manner described above, it is not possible to relate their positions to the shape of the object, adding complexity to the encryption or encryption of the object and therefore a security value. In addition, the individual lines of the stereo pairs can vary from finite length to become elementary points. In the case of a three-dimensional object observed in an ordinary way, while from a specific angle of observation some parts of the object are visible, other parts are not (for example surfaces) P1136 / 99MX remote sides): from different observation angles, different parts of the object are visible and different parts are hidden. For the substrate, according to the invention, to provide a realistic image of a three-dimensional object, the image needs to show certain parts of the object when the substrate is observed from certain angles, but not when viewed from others. Therefore, predetermined stereo pairs are preferably omitted in the set of stereo pairs for predetermined image points, so that the related image point is hidden when the substrate is observed from the corresponding observation angle. The global arrangement is such that different parts of the three-dimensional object are visible from different observation angles, to provide a realistic image of the object. A substrate according to the invention will comprise a large number of sets of stereo pairs, each set defining the same observable image point from different viewing angles, so that in total a larger number of different point images are created, which are separated horizontally and vertically and with different predetermined separations from the substrate plane. These point images P1136 / 99MX contribute to forming a three-dimensional image. Some of the image points can jointly define a linear image (for example the edge or boundary of an object or part of an object) while others can define a "shading" to provide the image of a surface. A three-dimensional object typically includes surfaces (e.g., side surfaces) that are at an oblique angle to the viewer, when the object is viewed from certain angles or range of angles. We have found that a good image definition can be achieved by a reduction in the density of the stereo pairs provided for the image of that oblique surface, in relation to the image of a surface that is being observed from the front. This allows a reduction in the total number of stereo pairs that must be formed on the substrate to be obtained. As already mentioned, the stereo pairs on the substrate can be arranged or arranged to provide more than one image. In this case, different images can be visible from different viewing angles.

BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the present invention will now be described, by way of example, only and with P1136 / 99MX to the accompanying drawings, wherein: Figures 1 to 4 are schematic diagrams that are used to explain the principles on which the present invention is based; Figure 5 is a diagram schematically illustrating a substrate according to the present invention; and Figure 6 is a diagram illustrating the effects of alternative profile grooves in cross section.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES With reference to Figures 1 and 2, in a substrate mode according to the present invention, a three-dimensional image is formed by a plurality of point images, each of which is created by a stereo pair. of grooves (or ribs) 14, 16 linear and short. In Figure 1, the slots 14, 16 are oriented to form the image of a point P at a distance behind the substrate, while in Figure 2, the slots are oriented to form the point image at a distance from the substrate. . Referring to Figures 1 and 2, we find that the distance of the ir. Point P from the substrate is essentially equal to the distance r from each P1136 / 99MX groove towards the intersection of the lines perpendicular to these grooves: the image "P" lies below the substrate for the grooves or ribs of Figure 1, which point upwards, one at another, and above the substrate of the grooves. slots or ribs of Figure 2, pointing downwards, one to the other.It will be appreciated that the point image P produced by each stereo pair of slots is visible only from a particular angle of observation (or a limited range of angles). If a spot image continues to be seen as the observer alters its angle of observation, then more stereo pairs are provided, each effective from its own angle of observation, and the successive stereo pairs can be moved in the relative position and orientation between yes, to ensure that the related spot image is essentially stationary as the observer moves the head side-by-side.Alternatively, the stereo pairs successive for a specific point image, that is to say that it is intended to provide an image of the same point as the observer moves the head, they can move in relative position and orientation relative to each other, so that the related point image appears to move as the observer alters his angle of observation. In this way, P1136 / 99MX The three-dimensional image can give the impression of an object that is moving or that is changing, instead of a static object. The above description assumes that successive stereo pairs, in relation to a particular point of image, they are placed along a line (with certain deviations from that line, according to the "displacements" to which reference has been made). However, in fact it is not necessary to limit the placement of the successive stereo pairs in this way. Referring to Figure 3, this shows a succession of stereo pairs, from + SP1 to -SPI, arranged to provide the point image P from different viewing angles. However, in this case, the stereo pairs are all placed on a horizontal line H. The angle? between the perpendiculars to the elements of each pair is constant for each pair, in order to provide light to the respective eyes of the observer. The distance (2d) between the elements of each pair varies according to the following: tan a = a / z so (a +? / 2) = (a + d, / z so (a -? / 2) = ( a - d) / z where the image point P appears at a distance Z behind the substrate plane and below P1136 / 99MX of the horizontal line on which the successive stereo pairs are aligned. Figure 4 shows the successive stereo pairs transposed to remain in a horizontal line, as described in relation to Figure 3. In the case of a three-dimensional object observed in an ordinary manner, while for a specific angle of observation certain parts of the object they are visible, others are hidden (for example, the rear surface or the remote side surfaces). To provide a realistic image of a three-dimensional object, the image needs to show certain parts of the object when the substrate is observed from certain angles, but not when viewed from others. Therefore, as shown in Figure 4, the stereo pairs are omitted for certain observation angles, so that the related image point is hidden when the substrate is observed from that angle. Referring to Figures 3 and 4, they show that a set of stereo pairs (to observe the same point of image from different viewing angles) can be arranged on a horizontal line H. The image point can be visible in a range of angles, as the observer moves his head towards P1136 / 99MX up and down relative to the substrate (along a line parallel to the plane of the substrate): the vertical parallax along this axis can be extended by providing several similar sets of stereo pairs that define the same point of image, on parallel horizontal lines, the elements of each set are "properly displaced (in relation to angle and / or horizontal position) with respect to the corresponding elements of the other sets. Referring to Figure 5, a substrate according to the invention will typically comprise a large number of sets of stereo pairs, each set defining the same observable image point from different viewing angles, so that a large number is created in total of point images, separated horizontally and vertically and to different predetermined separations with respect to the plane of the substrate. These point images contribute consequently to form a three-dimensional image. Some of the image points can jointly define a linear image (ie, the edge or boundary of an object), while others can define a "shading" to provide the image of a surface. For an image of a surface that is at an oblique angle to the observer, a P113S / 99MX good image definition due to a reduction in the density of the stereo pairs formed on the substrate ", in relation to the image of a surface that is observed from the front, as shown in Figure 6, the profile of the section The cross section of the slit determines the range of angles through which light is reflected and on which the image can be observed.This effect can be used so that different parts of the image are visible from different viewing angles: the effect can also be used to contribute to "shading" and control the brightness of the image.Preferably, a computer is used to generate data that define elements required to form a desired three-dimensional image, including the interruptions required to provide the correct obscuration of the parts of the image. image (corresponding to the parts of the object not visible from the corresponding observation angles) and also We also take into account the reduced densities of the stereo-speakers that can be used for the images of "oblique" surfaces. The preferred computer is arranged to determine the placement of the different stereo pairs in order to optimize the use of the surface area of the substrate. It can be used either P113S / 99MX mechanical engraving, electromagnetic exposure and / or other etching process to transfer the data to the required pattern of the stereo pairs on the first substrate. The first substrate is then processed and procedures (known in the art) are carried out to form a raised embosser. This stamper is used to print a second substrate or, for example, a coating of lacquer that is carried on a support member, to give the substrate or coating an enhanced pattern (the elements of the stereo pairs are formed, such as ribs or grooves). Alternatively, a printing plate can be formed so that the pattern of the stereo pairs can be printed on a substrate, for example, a document of value, using ink that is sufficiently reflective. The invention can also be used particularly as a security feature that is applied to documents or other products, the pattern of the elements is particularly difficult to reproduce, especially if the elements are transposed as shown in Figures 3 and 4, for example , since the pattern of the elements has no relation to the shape of the image they produce. It will be appreciated that with the transposition of the stereo pairs in the manner described, they can be P113S / 99MX is distributed through the surface of the substrate in such a way that the stacking of elements with different point images is avoided (and thus the intersection or interference between them is avoided), and the surface area of the substrate is used to the maximum.

P113S / 99MX

Claims (16)

1. NOVELTY OF THE INVENTION Having described the present invention; it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A substrate that is arranged to present a three-dimensional optical image to an observer, the substrate is formed with a multiplicity of pairs of elements optical, each pair of optical elements is arranged to direct light to the respective eyes of an observer, when it is placed at a predetermined viewing angle or within a limited range of viewing angles, thus providing the observer with an image of a point at a predetermined distance from the plane of the substrate, the multiplicity of pairs of optical elements are arranged so that the corresponding multiplicity of point images that they provide form the three-dimensional image.
2. 2. A substrate according to claim 1, wherein the optical elements are arranged to reflect the incident light towards the observer.
3. 3. A substrate according to claim 1, wherein the optical elements are arranged to refract light transmitted through the substrate to the observer. P1136 / 99MX
4. 4. A substrate according to any of claims 1 to 3, wherein the optical elements comprise grooves formed in the surface of the substrate.
5. 5. A substrate according to any of claims 1 to 3, wherein the optical elements comprise ribs formed on the surface of the substrate.
6. 6. A substrate according to claim 2, wherein the optical elements comprise reflective printing formed on the surface of the substrate.
7. A substrate according to any one of the preceding claims, wherein each pair of optical elements comprises two short linear elements, whose relative orientations determine the distance of the corresponding point image from the surface of the substrate.
8. A substrate according to any one of the preceding claims, wherein, for each point image, a set of pairs of optical elements is provided, so that the equivalent point images are visible from different viewing angles.
9. 9. A substrate according to claim 8, wherein, for at least one of the point images, the optical elements that relate to that point image are displaced from a common line. P1136 / 99MX
10. 10. A substrate according to claim 9, wherein, for at least one point image, the optical elements that are related to that point image are placed on a common horizontal line.
11. 11. A substrate according to claim 8, wherein, for at least some of the point images, selected pairs of optical elements are omitted so that those points are hidden for selected observation angles, thus providing for the removal of a hidden line and / or a hidden surface in relation to the three-dimensional image.
12. 12. A substrate according to any of the preceding claims, wherein, at least some of the point images together define a linear image.
13. 13. A substrate according to any of the preceding claims, wherein at least some of the point images together define a shading to provide the image of a surface of a three-dimensional object.
14. A substrate according to claim 15, wherein the point images define the shading to provide the image of a plurality of surfaces of a three-dimensional object, wherein the density of the optical objects for relatively oblique surfaces of the three-dimensional object is reduced in comparison with the P1136 / 99 X optical elements for less oblique surfaces of the object.
15. 15. A substrate according to any of the preceding claims, arranged to present a plurality of optical images to an observer, the optical images are visible from different viewing angles.
16. 16. A substrate according to any of the preceding claims, wherein the optical elements of different pairs have different profiles in cross section to control the brightness of the image and / or the shading of the image and / or the angle of observation. P1136 / 99MX