EP1914705A1

EP1914705A1 - Interlaced display device with an improved visual effect

Info

Publication number: EP1914705A1
Application number: EP06122373A
Authority: EP
Original assignee: Hansenne Yves
Current assignee: Hansenne Yves
Priority date: 2006-10-16
Filing date: 2006-10-16
Publication date: 2008-04-23

Abstract

Display device provided to display a sequence of two or more images (A,B,...) by imposing a relative translation movement parallel to a translation axis between a lenticular lens (1) and an interlaced printing (6) comprising n interlaced images (A,B,...) having a predetermined pitch m, the lenticular lens (1) comprising a plurality of lenticular elements (2) having a length x being equal to n times m, the back side of the lenticular lens (1) being masked by a opaque barrier (7) comprising an alternation of a opaque zone (8) having a length equal to or more than [(n - 1) x m] and a transparent zone (9) having a length ranging from 90% to 100% of m, said alternation being along the translation direction.

Description

The present invention relates to a display device provided to display a sequence of two or more images by imposing a relative translation movement parallel to a translation axis between a lenticular lens and an interlaced printing, wherein:

said interlaced printing comprising n interlaced images, each interlaced image having a predetermined pitch m,
said lenticular lens comprising a plurality of lenticular elements having a front side made of a curved surface, each curved surface having a same bending, and a back side having a length x being equal to n times m, said lenticular lens having a plurality of junction portions being each an inwardly curving portion, located between each lenticular element and a back side provided to be in contact with said interlaced printing,
means for maintaining the lenticular lens and the interlaced printing in close proximity, and
a driving system provided to impose said relative translation movement.

Display devices provided to display a sequence of two or more interlaced images through a lenticular lens are well known. Interlaced images are formed by decomposing each of several images into image elements equaling the number of curved surface in the lenticular lens. The background for lenticular lens with interlaced images can be found in US 5 464 445 .
The invention intends to target particularly display devices allowing the viewer to see a sequence of two or more different images through the lens by moving either the interlaced image or the lens (see for example WO 2006/082217 ) in a translation movement in the translation direction by a back and forth motion or by an up and down motion depending on the orientation of the lens and of the interlaced image. In such display devices for interlaced images, the viewer see the same image with both eyes in opposition to a stereoscopic display device where a dimensional effect is shown.
Interlaced display devices providing a sequence of several images are usually advantageous because they do not require the presence of video equipment nor the change of the image to be displayed. The transition period between two images is very short due to the fact that the pitch between two image elements is very small (usually about 300 µm). It is important to use lenticular lenses because the image elements (pitch of 300 µm) have to be magnified to be seen by the viewer.
Usually interlaced printings comprise n interlaced images. Each interlaced image is printed in y portions. Each portion presents a predetermined length being the pitch of the interlaced image m. that is to say that in the case of two interlaced images, from top to bottom, the first portion of the first image is followed by the first portion of the second image. The second portion of the first image is followed by the second portion of the second image. The third portion of the first image is followed by the third portion of the second image, etc. Between each portion of the first or of the second interlaced image, a transition zone is present. The transition zone can be a white line type, a coloured line type, a black line type or a zone where the image is changing.
A problem of ghosting arises when the interlaced image and the lenticular lens present a relative motion one to each other because the transition between two different images being interlaced can be seen by the viewer. Depending on the image content, the quality of the lenticular material, alignment precision of the interlaced image to the lenticular material, etc., the complete extinction of the first image does not occur prior to the second image being displayed due to the magnifier effect of the lenticular lens. The viewer thus sees the first image (Image A) completely and a less distinct version of the second image (Image B) in the background until the interlaced image or lenticular lens moves in the translation direction to a point where only Image B is displayed. The undesirable appearance of the less distinct image is referred to as ghosting.
The interlaced image is printed on support with one or more lines of image elements for each image printed under each curved surface. When displayed behind the lenticular lens, sequential lines from a particular view will fill each curved surface. Thus, as all the curved surfaces of the lenticular lens are viewed simultaneously, a particular image is projected to the viewer.
U.S. Pat. No. 5,581,402 discloses a method for producing an improved stereoscopic image in which adjacent lenticular image element sets are separated by image elements that are black or of another color, that are of varying brightness level, or that are printed with different exposure levels to improve stereoscopic viewing. The stereoscopic images are of the same scene. This patent does not address the ghosting problem of interlaced image display device.
US patent 6 405 464 provides a lenticular image product having flip images that eliminates the ghosting problem for this kind of device by eliminating the pixel interference from one image to another by composing transition data as complementary color background that would create a transitioning effect for moving from one image to another image. Such device solves partially the ghosting problem by providing a visual effect consisting of an optical illusion and of a "trompe l'oeil".
The drawback of adapting the interlaced image is that it requires a perfect analysis of the two or more images to be displayed in order to determine the most appropriate complementary color background of each interlaced image to create the transitioning effect. The cost of such interlaced image are therefore increased and the manufacturing of such interlaced image is time consuming and difficult to automate because of the customization for the interlaced image. In the advertising medium, such work load and constraint are unacceptable.
It is an object of the present invention to provide an effective solution to the ghosting problem stated above without requiring to adapt the printed interlaced image and without requiring any additional automation step to create the interlaced image.
It is another object of the invention to provide a lenticular lens display device being particularly adapted for advertising medium by its simplicity of manufacturing involving in particular no additional cost and/or no additional time.
Further, it is another object according to the invention to provide a lenticular lens display device providing a transition phase between two or more images which is invisible to the viewer thus providing a perfect visual effect being an essential condition in advertising.
According to a feature of the present invention, there is provided a display device as mentioned in the beginning, characterised in that back side of the lenticular lens is masked by a opaque barrier comprising an alternation of a opaque zone having a length equal to or more than [(n - 1) x m] and a transparent zone having a length ranging from 90% to 100% of m, said alternation being along the translation direction.
The opaque zones surprisingly increase the quality of the sequence of the images by reducing the display zone of each curved surface of the lenticular lens. This is very surprising because none would have thought to reduce the magnifying effect of the lens to reduce the transition between two images. Indeed, lenticular lenses are always used for their magnifying effect. Moreover, the interlaced image display device according to the invention transitions distinctly from one image to the next with complete extinction of the first image prior to the appearance of the next image. The opaque zones are preferably white opaque zones because they reflects ambient light and thus provides a perfect visual effect because the human eyes seeing both the same images are not adapted to see clear transition. The reflected light creates a "glare effect" preventing the viewer to see the transition between two images of the two or more interlaced images resulting in a complete extinction of the first image during the transition phase. An extinction of the first image can also be obtained by a black junction, however, the transition phase is seen by the viewer because the human eye sees perfectly such black image between the two image of the two or more interlaced images. Black images are not able to provide a perfect finishing resulting in a disdain from the advertising company. That is the reason why the opaque barrier, without being limited to, are preferably a light opaque zone, such as a white, a light grey, a right red opaque barrier. The white opaque zones being the most preferred.
White zones as such are known for example from US 2005/0152040 . In this document, the white zone is used as an intermediate coating. The effect of the intermediate coating according to this document is the ability to view digitally output image (typically not an interlaced image) without interference from an interlaced printing. In the construction according to US 2005/0152040 , the lenticular element is followed by the interlaced printing. Behind the interlaced printing is the intermediate coating which is followed by the digitally output image. The intermediate white coating acts as a separating support between two images by reflecting lights back to the eye of a viewer to eliminate background interference. The products created in this fashion typically include an interlaced image viewable through the lens from one direction, and an non interlaced image directly viewable from an opposite direction. The white coating is used as an enhancer of the clearness or vibrancy of images
Moreover, according to the invention, it is provided that whatever the number of interlaced images, the visual effect remains increased due to the fact that the length of the transparent zone being equal to or at most m and to the fact that the transparent zone is boxed by opaque zones making transitions invisible for the human eyes.
According to a preferred embodiment of the invention, each transparent zone is centred with respect to a median plane of each lenticular element forming the lenticular lens, in order to improve the magnifying effect of each lenticular element and to improve the quality of the visual effect.
According to the invention, n is an integer and is at least 2.
Indeed, it is also provided according to the invention that the interlaced printing comprises 2, 3, 4, 5, or even 6 interlaced images in order to render the display device more flexible in terms of images to be displayed. In the case of a large number of interlaced images, the transparent zone will become smaller and the opaque zones will become larger. This can reduce the light passing through the lenticular element. According to the invention, if the number of interlaced images is more than 2 or 3, provision is made to print the interlaced image on a transparent film that will increase the amount of light susceptible to pass through the display and this will therefore increase the quality of the visual effect for the human eyes.
Advantageously, the opaque barrier is integrated within the back side of the lenticular lens, thereby reducing the manufacturing costs and make easier the mounting step of the display device according to the invention.
In a variant, the opaque barrier is a transparent support comprising said alternation of opaque zones and transparent zones and provided to be placed towards the back side of the lenticular lens, between the interlaced images and the lenticular lens. The aforementioned variant according to the invention allows more flexibility for the user of the display device. Indeed, the user can choose if he wishes to add the transparent support comprising the opaque barrier or not. In certain cases, it can be more easy to add a separate opaque barrier than transform its manufacturing plant to manufacture the display according to the invention.
Advantageously, the relative translation movement is imposed to the interlaced printing or to the lenticular lens.
In a preferred embodiment, said means for maintaining the lenticular lens and the interlaced printing in close proximity are one or more of the followings : elastic means, pressure means, a concave lens, a convex lens.
It is important in order to obtain a perfect visual effect to ensure a contact is close proximity between the interlaced image and the lenticular lens. However, the close proximity should not prevent the relative movement between said lens and said interlaced images nor causing a wear effect due to the friction during the relative movement. Elastic means, pressure means such as a compressible material, a convex lens or a concave lens are particularly advantageous. For example, a homogenous pressure can be obtained in a device wherein a first support is placed behind the verso side of the interlaced images, the recto side being applied towards a convex lenticular lens. If a pressure strength is exerted by a deformation of the first support by the convex lenticular lens. The same applies if the first support is convex and if the lenticular lens is deformed by the first support.
Such exemplary means for maintaining the lenticular lens and the interlaced printing in close proximity are chosen from an elastic means, a spring or an elastic rubber, a counterweight means, or even any means able to exert a tension means and a restoring force.
Advantageously, m is between 10 µm and 1000 µm, preferably between 100 µm and 500 µm and most preferably about 300 µm.
In a preferred embodiment, lever means and pivot means are provided for adjusting the reciprocal position between said lenticular lens and said interlaced images, said lever means and said pivot means being provided for displacing either the lenticular lens or the interlaced images with a predetermined distance being at most of one pitch.
Other embodiments of the device according to the invention are mentioned in the annexed claims.
The invention relates also to a process for manufacturing a lenticular lens comprising the steps of forming said lens starting from an organic material being homogenous, isotropic and transparent to obtain a front side being made of a first plurality of curved surfaces and a second plurality of junction portions, each curved surface being separated from each other by a junction portion, and a back side being a flat surface.
The process according to the invention is characterised in that it comprises the steps of a opacification of each junction portion.
The step of a opacification of each junction portion is a step which can be easily integrated in a manufacturing process. As the opacification will be the same for each display device, automation of the process is very easy and does only involve a little cost increase which will be rapidly absorbed in view of the large number of lenticular lenses manufactured by large scale processes.
Other embodiments of the process according to the invention are mentioned in the annexed claims.
Other characteristics and advantages of the invention will appear more clearly in the light of the following description of a particular non-limiting embodiment of the invention, while referring to the figures.
Figure 1 is side view of a lenticular lens.
Figure 2 is an enlarged side view of the selected portion in figure 1 at the first time of the functioning cycle wherein the opaque barrier can be seen. The display device comprises 2 interlaced images and presents a two-time functioning cycle.
Figure 3 is also an enlarged side view of the selected portion in figure 1 but at the second time of the functioning cycle.
Figure 4 is a perspective view of the display device according to the invention using a concave lenticular element.
Figure 5 is an enlarged view of the selected portion in figure 4 showing how the opaque barrier is located.
Figure 6 is a perspective view of the display device according to the invention using a convex lenticular element.
Figure 7 is an enlarged side view of the selected portion in figure 1 at the first time of the functioning cycle. The display device comprises 3 interlaced images and presents a three-time functioning cycle.
Figure 8 is an enlarged side view of the selected portion in figure 1 but at the second time of the functioning cycle.
Figure 9 is an enlarged side view of the selected portion in figure 1 but at the third time of the functioning cycle.
In the drawings, a same reference sign has been allotted to a same or analogous element of the display device according to the invention.
Fig. 1 shows the device according to the invention where it can be seen the lenticular lens 1. The lenticular lens comprises a plurality of lenticular elements 2 having a front side 3 made of a curved surface 3 and a back side 4. The back side of each lenticular element has a length of x and each curved surface 3 of each lenticular element 2 presents the same bending. The lenticular lens 1 has a plurality of junction portions 5 being each an inwardly curving portion. Each junction portion 5 is located between each lenticular element 2.
As it can be seen in figure 2, the display device according to the invention comprises an interlaced printing 6 comprising 2 interlaced images (A, B) and having a translation direction. The translation direction is presented in figure 2 by an arrow T. Dotted line M illustrates the magnifying effect of the lenticular element. Each interlaced image (A, B) having a predetermined pitch of m being preferably of 300 µm. According to this embodiment, n = 2 and the equation to be applied is x = n times m.
The display device according to the illustrated embodiment of the invention is provided to display a sequence of two images (A, B). To this end, a driving system (not shown) is provided to impose a relative translation movement between said lenticular lens 1 and said interlaced printing 6 parallel to the translation direction. The translation movement can either be applied onto the lenticular lens 1, the interlaced printing 6 being immobile or to the interlaced printing 6, the lenticular lens 1 being immobile or even to both lenticular lens 1 and interlaced printing 6 but in opposite directions.
The driving system to be used can be for example one of the known type of the driving system disclosed in WO 2006/111703 or in WO 2006/082217 .
As it can be seen, the back side 6 of the lenticular lens 1 is masked by a opaque barrier 7 comprising an alternation opaque zones 8 and transparent zones 9. The length of the opaque zone is [(n - 1) x m] and the length of the transparent zone is m. The alternation is along the translation direction (see arrow T).
In more details, the translation direction is the direction to be followed during the translation movement either by the interlaced printing 6 or the lenticular lens 1 to see the sequence of both images (different images A and B). The back side 4 of the lenticular lens is provided to be in contact with said interlaced printing 6.
Since the number of interlaced images is 2, the display device presents a two-time functioning cycle. Figure 2 illustrates the display device according to the invention during the first time (t = 0) of the functioning cycle. According to this example, the displayed image through the transparent zone is image B.
As it can be seen, each transparent zone 9 is centred with respect to a median plane of each lenticular element 2 of the plurality of lenticular elements 2 forming the lenticular lens 1.
Figure 3 shows the same embodiment as in figure 2. However, figure 3 illustrates the display device according to the invention during the second time (t = 1) of the functioning cycle. According to this example, the displayed image through the transparent zone is image A.
In the preferred embodiment shown in figure 2 and 3, the back side 4 of the lenticular lens 1 comprises the opaque barrier 7.
Alternatively, the opaque barrier 7 can be printed on a transparent support (not shown). In this case, the transparent support comprising the same alternations that those shown in figure 2 and 3 can be pasted on the back side 4 of the lenticular lens 1.
Figure 4 is a perspective view of the display device according to the invention using a concave lenticular lens 1. In this preferred embodiment, the lenticular lens 1 is shaped as concave planar element. The lenticular element is concave with respect to the viewer 12. This shape of lenticular lens, for example, in cooperation with elastic means 10, exert a strength on the interlaced printing 6. Said elastic means 10 acting as streching means provided to strain said interlaced printing 6 towards the lenticular lens 1. The lenticular lens 1 exert on its turn a surface strength towards the printed side of the interlaced printing 6. This result in an optimal focal distance between said interlaced printing 6 and said lenticular lens 1. The elastic means 10 are for example passed through holes 11 provided in the lenticular lens and in the interlaced printing.
Figure 5 is an enlarged view showing in details the opaque zones of the alternation. The lenticular lens 1 has a plurality of junction portions 5. Each opaque zone 8 is sensibly located under each junction portion in a centred fashion. Each transparent zone 9 is centred with respect to a median plane of each lenticular element 2 forming the lenticular lens 1.
According to the invention, the lenticular lens 1 can be formed starting from an organic material being homogenous, isotropic and transparent to obtain a front side being made of a plurality of curved surfaces 3 and a plurality of junction portion 5.
For example, the invention contemplates to manufacture said lenticular lens 1 via an extrusion step of an organic material such as polyethylen, polycarbonate, polyester, polyether or other transparent polymers such as polyvinyl, polymethylmethacrylate and combinations thereof. The extrusion step would preferably be performed through an extrusion die comprising a first surface being a flat surface and an opposite surface comprising a first plurality of curved surface and a first plurality of junction portion, each curved surface being separated from each other by a junction portion.
In a variant, it is intended to form said lenticular lens by means of a calendaring step followed by or simultaneous with a stamping step of organic materials as mentioned before in order to form said front side 3 and said back side 4 of said lenticular lens 1 and a step of punching provided to form said front side 3 and said back side 4 of said lenticular lens.
The opaque barrier 7 according to the invention is made by a opacification of each junction portion 5. The opacification can be made by frosting, etching, painting, and stamping each junction portion 5 of said lenticular lens 1.
Figure 6 is a perspective view of a variant according to the invention wherein the lenticular lens is shaped as a convex planar element. The lenticular element is convex with respect to a viewer 12. This shape of lenticular lens, for example, in cooperation with elastic means 10, exert a strength on the interlaced printing 6. Said elastic means 10 acting as streching means provided to strain said interlaced printing 6 towards the lenticular lens 1. The lenticular lens 1 exert on its turn a surface strength towards the printed side of the interlaced printing 6. This result in an optimal focal distance between said interlaced printing 6 and said lenticular lens 1. The elastic means 10 are for example passed through holes 11 provided in the lenticular lens and in the interlaced printing for maintaining between them a close proximity.
Figure 7 to 9 illustrates another variant according to the invention, wherein the number of interlaced images is 3 (n = 3).
As before, the translation direction is represented by arrow T and the dotted line M illustrates the magnifying effect of the lenticular element. Each interlaced image (A, B, C) present a pitch of m.
The display device according to this preferred embodiment is provided to display a sequence of three images (A, B, C). Therefore, the display device presents a three-time functioning cycle. Figure 7 illustrates the display device according to the invention during the first time (t = 0) of the functioning cycle. According to this example, the displayed image through the transparent zone is image B.
Figure 8 shows the same embodiment as in figure 6. However, figure 8 illustrates the display device according to the invention during the second time (t = 1) of the functioning cycle. According to this example, the displayed image through the transparent zone is image C.
Figure 9 shows the same embodiment as in figure 6. However, figure 9 illustrates the display device according to the invention during the third time (t = 2) of the functioning cycle. According to this example, the displayed image through the transparent zone is image A.
Although the preferred embodiments of the invention have been disclosed for illustrative purpose, those skilled in the art will appreciate that various modifications, additions or substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
For example, provision is made according to the invention to provide lever means and pivot means (not shown) for adjusting the reciprocal position between said lenticular lens 1 and said interlaced images A and B, said lever means and said pivot means being provided for displacing either the lenticular lens 1 or the interlaced images (A,B) with a predetermined distance being at most of m.

Claims

Display device provided to display a sequence of two or more images (A,B,...) by imposing a relative translation movement parallel to a translation axis between a lenticular lens (1) and an interlaced printing (6), wherein:
- said interlaced printing (6) comprising n interlaced images (A,B,...), each interlaced image (A,B,...) having a predetermined pitch m,

- said lenticular lens (1) comprising a plurality of lenticular elements (2) having a front side (3) made of a curved surface (3), each curved surface (3) having a same bending, and a back side (4) having a length x being equal to n times m, said lenticular lens (1) having a plurality of junction portions (5) being each an inwardly curving portion, located between each lenticular element (2) and a back side provided to be in contact with said interlaced printing (6),

- means (10,11) for maintaining the lenticular lens (1) and the interlaced printing (6) in close proximity, and

- a driving system provided to impose said relative translation movement,
characterized in that the back side of the lenticular lens (1) is masked by a opaque barrier (7) comprising an alternation of a opaque zone (8) having a length equal to or more than [(n - 1) x m] and a transparent zone (9) having a length ranging from 90% to 100% of m, said alternation being along the translation direction.
Display device according to claim 1, wherein each transparent zone (9) is centred with respect to a median plane of each lenticular element (2) forming the lenticular lens (1).
Display according to claim 1 or claim 2, wherein the opaque barrier (7) is a white, a light grey, a light red, a light pink, a light yellow and any other light coloured opaque barrier (7), the white opaque barrier (7) being the most preferred.
Display according to anyone of the precedent claims, wherein n is an integer and is at least 2.
Display device according to anyone of the claims 1 to 3, wherein said opaque barrier (7) is integrated within the back side of the lenticular lens (1).
Display device according anyone of the claims 1 to 3, wherein said opaque barrier (7) is a transparent support comprising said alternation of opaque zones (8) and transparent zones (9) and provided to be placed towards the back side of the lenticular lens (1), between the interlaced images (6) and the lenticular lens (1).
Display device according to anyone of the preceding claims wherein the relative translation movement is imposed to the interlaced printing (6).
Display device according to anyone of the claims 1 to 5, wherein the relative translation movement is imposed to the lenticular lens (1).
Display device according to anyone of the preceding claims, wherein said means (10, 11) for maintaining the lenticular lens (1) and the interlaced printing (6) in close proximity are one or more of the followings : elastic means (10), pressure means, a concave lens, a convex lens.
Display device according to anyone of the preceding claims, wherein m is between 10 µm and 1000 µm, preferably between 100 µm and 500 µm and most preferably about 300 µm.
Display device according to anyone of the preceding claims wherein lever means and pivot means are provided for adjusting the reciprocal position between said lenticular lens and said interlaced images, said lever means and said pivot means being provided for shifting either the lenticular lens or the interlaced images with a predetermined distance being at most of m.
Process for manufacturing a lenticular lens comprising the steps of forming said lenticular lens (1) starting from an organic material being homogenous, isotropic and transparent to obtain a front side being made of a first plurality of curved surfaces (3) and a second plurality of junction portions (5), each curved surface (3) being separated from each other by a junction portion (5), and a back side being a flat surface,
characterized in that it further comprises the step of opacification of each junction portion (5).
Process according to claim 11, wherein said step of forming said lenticular (1) lens is chosen in the group consisting of an extrusion step through an extrusion die of said organic material, said extrusion die comprising a first surface being a flat surface and an opposite surface comprising a first plurality of curved surface and a second plurality of junction portion, each curved surface being separated from each other by a junction portion, a calendaring step followed by or simultaneous with a stamping step of said organic material in order to form said front side and said back side of said lenticular lens and a step of punching provided to form said front side and said back side of said lenticular lens.
Process according to claim 11 or claim 12, wherein said opacification is chosen in the group consisting of frosting, etching, painting, and stamping each junction portion of said lenticular lens.