WO2008030080A1

WO2008030080A1 - Device for displaying virtual three-dimensional objects

Info

Publication number: WO2008030080A1
Application number: PCT/NL2006/000447
Authority: WO
Inventors: Ronald Van De Bos; Johann Henricus Houf; Willibald Mattheus Petrus Ahout
Original assignee: Medialusion B.V.
Priority date: 2006-09-08
Filing date: 2006-09-08
Publication date: 2008-03-13

Abstract

A description has been given of a display device for presenting virtual three-dimensional objects, which includes: a case (2; 62) with a first view opening (4; 64); a transparent foil (10) set up at an angle behind the view opening (4; 64) with smooth, reflecting surfaces; an active, light-omitting image display device (20; 66), set up between the view opening (4; 64) and the foil (10).

Description

Title: Device for displaying virtual three-dimensional objects

The present invention, broadly speaking, refers to displaying virtual objects. More in particular, the present invention refers to a device for displaying a virtual object by forming light image of the object. American patent 5865519 describes an example of such a device, which includes a transparent, stretched foil. This known device is a set-up especially suitable for theaters and the like, the transparent foil being set up in a plane at an angle of approximately 45° to the floor of the stage, in the direction of the viewers. Since the foil is transparent, it is not visible to the viewers. The floor of the stage in front of the foil, that is to say, on the side towards the viewers, is a projection plane on which a light image is projected. Behind the foil, that is to say, on the side away from the viewers, there may be a presenter, who is visible to the viewers through the transparent foil. The light image projected on the projection surface is reflected on the foil, and appears to the viewers as a virtual image behind the foil, coinciding with the presenter. Because of its size and the use of a stage, this known device is suitable for theaters and the like, but not for display windows and the like. The known set-up is capacious, complicated to install, and has comparatively many components. For example, projecting an image on the floor of the stage requires an image source disposed above the stage, at the upper extremity of the foil, which projects its image through a mirror on the projection plane.

Therefore, an objective of the present invention is to provide a device of the type mentioned in the introduction suitable for use in display windows and the like, in order to thus be able to provide a virtual display window.

In particular, the present invention intends to provide a virtual projection system that takes up little floor area. In addition, the present invention intends to provide a virtual projection system that is easy to set up and put away, so that it is suitable to be used at night and put away during the day. With the known set-up, viewers can only see virtual images from one side. A special objective of the present invention is to provide a virtual display window or virtual display space, enabling viewers to look in from two opposite sides, in which case they may see different virtual objects. Furthermore, the present invention intends to provide a virtual display window which can be configured from a distance.

Another objective of the present invention is to provide a device for displaying virtual, three-dimensional images easier to set up that the known device.

The known device has, in front of the foil, a passive, reflecting projection plane on which an image source projects a light image. According to a first aspect of the present invention, this passive projection plane has been replaced by an active, light-emitting image display device, like a display screen (CRT, LCD, plasma, etc.) .

In the known device, the foil is completely stretched, and a virtual image is created behind the foil because of the reflection in the foil of the real image in front of the foil. According to a different aspect of the present invention, a foil is used, set up as transparent projection screen, and a real image is created on the foil by projection.

These and other aspects, features and advantages of the present invention will be elucidated by the description given below, referring to the drawings in which equal reference numbers indicate equal or similar parts and in which: figure 1 shows a schematic perspective view of a display device according to the present invention; figures 2A-2E are views illustrating different embodiment variants of a virtual display window; figures 3A-3B are block diagrams that illustrate the control of an image display device in the virtual display window according to the present invention; figure 4 is a schematic side-view of a special embodiment of a virtual display window according to the present invention; figure 5 is a schematic side-view of an alternative; figures 6A-6C illustrate correction methods for correcting distortion of a projection; and the figures 7A-7B are schematic top views illustrating another embodiment of a display device according to the present invention.

Figure 1 shows a schematic perspective view of an embodiment of a display device 1 according to the present invention. This display device 1 is suitable for use as display window to display virtual three-dimensional objects, and therefore will also be referred to hereinafter as virtual display window.

The virtual display window 1 in this example includes a case 2, completely closed with the exception of a view opening 4 in a front plane 3. For the sake of simplicity, the case 2 is represented as a cube, but this is not necessary. Opposite the view opening 4, the case 2 has a rear wall 7. In the case 2, a transparent foil 10 is arranged between the view opening 4 and the rear wall 7 in such a way that, viewed from the view opening, the foil 10 covers the rear wall 7. The foil 10 is stretched, and situated in a plane at an angle to the view opening 4. Thus, the foil 10 has a first end edge 11 basically parallel with the view opening 4 and situated relatively close to the view opening 4, and a second end edge 12 across from the first end edge 11 and parallel to it, which second end edge 12 is situated at a larger distance from the view opening 4 than the first end edge. Hereinafter, these two end edges will also be referred to as proximal end edge 11 and distal end edge 12. In a practical embodiment, the foil 10 will have a rectangular outline, but this is not essential.

It should be mentioned that the features described above are not essential. The invention may be implemented as a box, offering the advantage that the entire set-up is easy to transport. If that box is rectangular, and the foil extends from wall to wall, the foil will have end edges as described above. However, it is not necessary for the foil to extend from wall to wall; the contour of the foil therefore could have any form; for instance, even a circular foil could serve. In this context the only matter of importance is that the foil is stretched, without wrinkles.

In addition, it is not necessary that the invention be implemented with a foil, although this is preferable. Instead of a foil, a thin, transparent sheet of glass could be used for instance. In theory, even a refraction prism could be used, but that has the disadvantage of large dimensions and a higher weight. In this context the only matter of importance is that a member is used that on the one hand is transparent enough and on the other hand has a level surface with sufficient mirror-reflective properties. This could also be achieved, for instance, with a partially metallized mirror. When using a sheet (of glass) , it is advisable to have the thickness be as thin as possible to minimize distortion of the illusion of a virtual 3D-object as a result of multiple reflections .

In addition, it is not necessary that the invention be implemented with a separate box. When used in an existing display window, this display window itself can serve as a "box". In this context, the only matter of importance is that the possibility exists to reduce or eliminate interfering ambient light. If the surroundings are sufficiently dark, no walls or screens are necessary.

In the situation of a box, that box does not necessarily have to have a rear wall. In the event that the display window itself is serving as a "box", usually there will be no rear wall. In that case, depending on the dimensioning of the "case", the virtual image may be situated beyond the case.

The foil 10 divides the inner space of the case 2 in two parts, namely a first part 5 adjacent to the view opening 4 and therefore, viewed from outside the view opening 4, situated in front of the foil 10, and a second part 6 adjacent to the rear wall and therefore, viewed from outside the view opening 4, situated behind the foil 10. Hereinafter, these two parts will also be referred to as front section 5 and rear section 6.

In the front section 5, between the distal end edge 12 and the view opening 4, an active, light-emitting display screen is arranged, directed towards the foil 10.

Since the foil 10 may be identical to the foil described in the American patent 5.865.519, no further description of this foil is necessary. Suffice it to say that the foil is made of a good transparent material, and that the surfaces of the foil 10 are exceptionally smooth so that they possess good reflecting properties.

Depending on the desired effect, the front plane 3 with the view opening 4 may be a side plane, top plane or bottom plane of the case 2. In that case there are different possibilities for the orientation of the foil 10 and the display screen 20, as will be explained referring to figures 2A-2E, representing the case always in the form of a block.

In a possible embodiment, the front plane 3 with the view opening 4 is a side plane. Figure 2A is a schematic side view of this embodiment variant. The case 2 has a bottom wall 22 and a top wall 23; the rear wall 7 is again a sidewall. The display screen 20 is disposed at the bottom 22 of the case 2. A raised edge 3a of the front plane 3 conceals the display screen 20 from the view of an observer outside the case 2. The proximal end edge 11 of the foil 10 is situated near the top wall 23, at a short distance from the view opening, and the distal end edge 12 of the foil 10 is situated near the bottom wall 22, at a larger distance from the view opening 4. An observer W outside the case 2, looking through the view opening 4, sees the reflection of the display screen 20 in the foil 10, which is perceived by the observer as a virtual image 20' behind the foil 10. Depending on the dimensioning of the case 2, that virtual image 20' is situated in front of the rear wall 7, and thus seems to be floating in the rear section β of the case 2. Although the virtual image 20' is, in fact, a two-dimensional image, it is possible to display images on the display screen 20 of three-dimensional objects so that the observer is deluded into thinking that the corresponding virtual image in the virtual reflection image 20' is a three- dimensional image, in particular when those objects are moving. This three-dimensional illusion is achieved in particular because the foil 10 is transparent and the observer also sees the rear section 6 through the foil 10, with the real three-dimensional objects set up there, as a result of which the observer experiences a sensation of depth and three- dimensionality. The three-dimensional illusion is enhanced if the original image of the object in question shows that object in a dark space and/or against a dark background. Thus, the virtual image seemingly only contains the image of the object concerned: the original surroundings and/or background are hardly visible, if at all, and instead the observer sees the real surroundings and background in the space behind the foil.

Figure 2B shows a variant of the set-up of figure 2A, in which the display screen 20 is disposed at the top wall 23 of the case 2, the proximal end edge 11 of the foil 10 being situated near the bottom wall 22 of the case 2 and the distal end edge 12 of the foil 10 situated near the top wall 23 of the case 2. This variant works in the same way as the variant of figure 2A, on the understanding that on the bottom 22 of the rear section 6 of the case 2, there is more room to place objects.

In the embodiment variants of figures 2A and 2B, the plane of the foil 10 is defined by a horizontal line and a ^"line at an angle to the horizontal. That is why in this case, the foil 10 will also be referred to as a horizontal foil. The said angle may be 45°, but could also be larger or smaller than 45° depending on the desired effects. Figures 2C and 2D are schematic top views illustrating two mirror-symmetrical embodiment variants in which the foil 10 will be referred to as a vertical foil, because the plane of the foil 10 in those cases is defined by a vertical line and a line at an angle to the vertical. Here, the display screen 20 is disposed at a vertical plane. Figure 2C illustrates a situation in which the display screen 20 is disposed at a left wall (viewed from the observer outside the case 2) 25L, the proximal end edge 11 of the foil 10 being situated near the opposite right wall 25R and the distal end edge 12 of the foil 10 being situated near the left side wall 25L. Figure 2D illustrates the reverse situation in which the display screen 20 is disposed near the right side wall 25R, the proximal end edge 11 of the foil 10 being situated near the left side wall 25L and the and the distal end edge 12 of the foil 10 being situated near the right side wall 25R.

Figure 2B illustrates another method of describing the orientation of the foil 10 in relation to view opening 4 and the display screen 20. Reference number 31 refers to a line of sight, i.e. the intended line along which an observer W looks through the view opening 4 to the center of the virtual display screen 20'; this line of sight 31 crosses the foil 10 at a point 32. Reference number 33 refers to a line that connects the point 32 mentioned above with the center of the display screen 20. Reference number 34 refers to a dotted line situated in the plane spanned by the lines 31 and 33, passes through the intersection 32 mentioned above, and meets lines 31 and 33 at equal angles. The foil 10 is at right angels to the line 34 last mentioned. The display device 1 may also be embodied as a table or the like, in which the view opening 4 is made in the top plane 3, as illustrated by the side view of figure 2E. In that case, the line of sight 31 is vertically oriented, and the normal on the display screen 20 is horizontally oriented. The set-up is rotation symmetric in relation to the vertical; the obliquely disposed foil 10 is horizontally oriented.

The display device 1 can be used in different ways. It is possible, for instance, that the rear section 6 is completely empty, and that the rear wall is black and/or not illuminated. In that case, the observer only sees the image of the display screen 20 reflected by the foil 10. The observer thus sees a virtual image of the representation displayed on the display screen, which virtual image seems to be floating in the interior 5 of the case 2. However, a more impressive 3D- impression is obtained if one or more real objects V are arranged in the rear section 6, and if illumination is installed in the rear section 6 so that the observer also sees these real objects V, given that the foil 10 is transparent. The observer will not perceive the foil 10 itself at all. The observer experiences the sensation that the virtual image of the representation displayed by display screen 20 seems to be floating between the real objects V, and sometimes through these objects V. Of course, the resulting effect will also depend on the images displayed by the display screen 20: optimum effects are achieved if these images are moving images, in which case the observer experiences the better illusion of a virtual three-dimensional image. As a result, the display device 1 exerts a special attraction on the observer, and is particularly suitable for use as display window or the like.

Figure 3A is a block diagram that illustrates that the display screen 20 can receive the images to be displayed from a memory device 41, 42, for instance a video tape 41 or an optical disk 42 (CD, DVD, etc.), read by an corresponding reader 40, for instance a video-player, CD-player, DVD-player, etc. It is also possible that the images to be displayed are stored on a hard disk 43 of a PC 40. However, a limitation of this configuration is that the images to be displayed are restricted to that what is stored in the memory devices 41, 42, 43. If another representation by the display device 1 is desired (or a display of other objects by the virtual display window) , the contents of these memory devices must be replaced.

Figure 3B illustrates another embodiment, in which a control unit like a PC 40 is connected to a network 44 like, for instance, the Internet, and thus receives the images to be displayed from a distant source (streaming video) . This way, it will always be possible to determine from a distance which representation will be displayed in a certain virtual display window 1 without any intervention being required at that particular virtual display window. In the case of a chain of stores with several stores and therefore several display windows, it will then be possible to control the actual "contents" of all display windows from a central location.

It is also possible that a control unit like, for instance, the PC 40 mentioned above, disposes of a collection of images from different objects, for instance stored on a hard disk 43 (figure 3A) , and that the control unit is configured to receive control instructions through a network 44 (figure 3B) like, for instance, the Internet, a telephone network, etc., that instruct the control unit to change the displayed images. For instance, the change can mean that another view is given of the same object, or that the object is moved in another way (rotation at a different speed, in another direction, on another axis) . The change can also mean, for instance, that another object from the memory 43 is displayed. With this it is therefore possible that passers-by determine the actual contents of the display window, so that the display window can be regarded as an interactive display window.

Figure 4 is a schematic side view of a special embodiment of a display device 60 according to the present invention. This display device 60 has a case 62, for instance in the form of a cube or a rectangular box, with an inner space 65 and two view openings 64 and 74 on opposite sides. The intended direction of view is referred to by a line of sight 61, passing through the two view openings 64 and 74. In the case 62, a transparent reflecting foil 10 is arranged, in a way comparable to the way described above, therefore at an angle to the line of sight 61. Thus, the foil 10 has a top edge 11 situated near a top wall of the case 62, and a bottom edge 12 situated near a bottom wall of the case 62. The bottom edge 12 is situated closer to the first view opening 64 than the top edge; thus, in relation to the first view opening 64, the bottom edge 12 can be regarded as proximal end edge and the top edge 11 as distal end edge; in relation to the second view opening 74, this is just the opposite.

At the top wall of the case 62, a first display screen 66 is installed between the first view opening 64 and the top edge 11 of the foil 10. At the bottom wall of the case 62, a second display screen 76 is installed between the second view opening 74 and the bottom edge 12 of the foil 10. Although these two display screens may be displaced somewhat relative to each other, in the represented example they are placed precisely opposite each other so that their central axes (normals in the middle of their projection surface) coincide with each other, according to the line 71, which is preferably at right angles to the line of sight 61. In the interior 65 of the case 62, no real objects are present. An observer can view through the case 62, either from the first view opening 64 or from the second view opening 74. Two observers can also view through the case 62 from both view openings 64 and 74 at the same time: they will then see each other through the transparent foil 10. A first observer looking through the first view opening 64 will additionally experience the illusion that there are virtual three- dimensional objects in the inner space 65, beyond the foil 10, being the reflection in the foil 10 of the images displayed by the first display screen 66. Likewise, a second observer looking through the second view opening 74 will experience the illusion that there are virtual three-dimensional objects in the inner space 65, beyond the foil 10, being the reflection in the foil 10 of the images displayed by the second display screen 76. If the display screens 66 and 76 display different representations, both observers will see different objects inside the case 62.

It is noted that depending on the geometry of the case 62 and the position of the foil 10, the virtual three-dimensional objects seem to be closer or further away: virtually, they can be situated within the house 62 or outside the house 62, beyond the opposite view opening, and thus, for instance, coinciding with the head of an observer on the opposite side of the case 62. It is noted that, above, figure 4 has been described as a schematic side view of the display device 60. In that case the foil 10 will be of the horizontal type, and the normal on the surface of the foil 10 will be situated in a vertical plane. However, it is actually possible to rotate the entire set-up on the line of sight 61 by a random angle: this does not change the observed effects and the explanation thereof. With such rotation by 90°, the normal on the surface of the foil 10 will be situated in a horizontal plane, and figure 4 may be considered as a top view of the situation in question. Figure 5 schematically illustrates another embodiment of a display device 100 according to the present invention. The display device 100 has a case 102 with a front wall 103 and a view opening 104. A wall opposite the view opening 104 is referred to as rear wall 107. At a distance from the rear wall 107, a stretched foil 110 is arranged in the case 102, preferably more or less at right angles to a line of sight 106 passing through the view opening 104. In this embodiment, the same applies to the case as explained in respect of the preceding embodiment. Likewise, the same applies in respect of the foil dimensions as mentioned in the preceding embodiment, and the foil 110 can also be replaced here with a thin sheet of glass. In this case, it is important to use a semi-transparent projection member, i.e. a member that on the one hand is transparent enough so that an observer can see the objects and background behind the foil, and on the other hand has a feature so that it is suitable for the projection of light images. That feature comes to expression in a certain degree of mattness and can be obtained, for instance, by a certain degree of surface roughness, or the presence of a small amount of pigment on the surface or in the material. Below, by way of an example, it is assumed that the foil 110 has a front surface 110a that is slightly rough.

In front of the foil 110, i.e. on the side of view opening 104, an image projector 115 is set up. The image projector can be any suitable projector, for instance a beamer, such as known per se. The projector 115 is concealed from an observer, for instance behind a partition 105. The projector 115 is directed to project an image 120 on the foil 110, which can be observed by an observer through the view opening 104. As a result of the slightly rough front surface 110a, the foil 110 is suitable to function as projection screen for the image projected by projector 115. Because the foil 110 is of a transparent material, the observer can also view through the foil. Behind the foil 110, i.e. between the foil 110 and the rear wall 107, several real objects will be placed during use that will provide a three-dimensional context .

If the foil 110 is completely transparent and has a completely smooth surface, the image 120 projected on the foil 110 is not visible to the observer, and the observer only sees the objects V placed behind the foil 110. The observer sees those objects as if the foil 110 were absent. If the surface roughness of the front surface HOa of the foil 110 is too high, the foil 110 itself will become visible as a slightly milky glare before the objects V and the rear wall 107, and the observer will not be able to see the objects V and the rear wall 107 or will not see them properly. The effect of a virtual three-dimensional image can only be achieved well if the observer perceives both the image projected on the foil 110 and the objects V placed behind the foil 110. This requires an adequate combination of the surface roughness of the transparent foil 110, the light intensity of the projector 115 as well as the level of illumination of the objects V behind the foil 110. If the illumination of those objects V behind the foil 110 is too weak, the image projected on the foil 110 is predominant. If the illumination of those objects V is too strong, those objects V are predominant and the image projected on the foil 110 hardly attracts any notice. A proper adjustment of the parameters mentioned above will be a question of trying in practice, but can be carried out by an expert with the information given above without difficulties.

With the set-up illustrated by figure 5, the projector is situated, in relation to the foil 110, on the side of the observer. The image perceived by the observer is thus originating from reflection by the foil 110 of the image projected by the projector 115. Alternatively, it is also possible to set up the projector on the other side of the foil, viewed from the observer beyond the foil; in that case, the image perceived by the observer is originating from transmission through the foil 110 of the image projected by the projector 115. Then, the projection medium 110 can be placed closer to the observer. It is also possible that a display windowpane, possibly equipped with a mat, transparent foil adhered to it, is used as projection medium. The projector 115 can be situated on the left or on the right of the view opening 104. For this situation, figure 5 can be regarded as a top view. However, it is also possible that the projector 115 is set up under the view opening 104, in which case figure 5 can be regarded as side view. Evidently, a mirror-symmetric situation is also possible, in which the projector 115 is set up above the view opening 104.

Figure 5 shows that the projector 115 generates a conical beam of light, with a centerline 117. Since the projector 115 is set up off-center in relation to the view opening 104, whereas the center line 117 of the conical beam of light 116 is directed approximately to the center of the foil 110, the patch of light 120 projected by the projector 115 on the foil 110 inevitably will be distorted, like for instance is known with the use of slide projectors and overhead projectors. Figure 6A illustrates the distortion that occurs.

Assume that the conical beam of light 116 has a square cross section, like shown by the square 121. If the centerline 117 of the beam would be directed perpendicular to a projection plane, the projected patch of light would have the square contour 121. The position of the centerline 117 of the beam is indicated by a central circle. Assume that the projection plane in question would be rotated on a horizontal line 123, moving the lower side of that projection plane towards the projector: this corresponds to a situation in which the projector 115 is placed right underneath the view opening 104 , and the center line 117 of the conical beam of light 116 is therefore directed at an upward angle. The projected patch of light will then have a trapezoidal contour 122. Since the top of the beam of light 116 touches the foil 110 at a larger distance than the bottom of the beam of light 116, the projection of the top of the beam of light 116 has a larger width than the projection of the bottom of that beam, as a result of which that trapezoidal contour 122 has its short horizontal side at the bottom.

Not only the form of the projected patch of light 120 is distorted in the way illustrated in figure 6A, also all projected images in that patch of light are affected by the same distortion.

It is known in practice to prevent this distortion by a software correction of the generated image, as illustrated in figure 6B. With this correction technique, which is known for beamers for instance, a generated square beam of light is distorted in such a way that it has a trapezoidal cross section, as illustrated with the line 131. The trapezoid is such that the crosswise dimension on the top is smaller than the crosswise dimension at the bottom. With oblique projection, the width of the top of the beam of light is enlarged, and the width of the bottom of the beam of light is reduced, as explained above, so that with proper dimensioning of the beam form 131, the result is a projected patch of light 132 with basically a square contour.

However, this correction technique only works within certain limits. In addition, this correction method can only be applied by adapted projectors. The present invention also proposes an alternative correction method. The present invention proposes to distort the recorded image during shooting according to a trapezoidal distortion as illustrated in figure 6C. In figure 6C, an original object 141 is represented as a square. A deliberately distorted shot of this original is represented as a trapezoid 142. As a result of this distortion, the width at the top is reduced compared to the original, and the width at the bottom is enlarged compared to the original.

When this distorted image 142 is projected without correction, in the way illustrated in figure 6A, the result is a projected image without distortion. This is illustrated in figure 6D.

Assume that the distorted image 142 is projected by means of a beam of light with a square cross section, at right angles to a projection plane. Thus, the projected patch of light would have a square contour 143, and in that patch of light, the image 142 would be displayed without any further distortions, therefore as an undistorted trapezoid, as illustrated in figure 6D. However, if this beam of light is projected obliquely, the distortion explained by means of figure 6A occurs, the projected patch of light distorting into a trapezoidal patch of light 144, as illustrated in figure 6E, in which the top of the patch of light is wider and the bottom of the patch of light is narrower. In the same way, the top of the image 142 broadens and the bottom of the image 142 is made narrower so that with a proper set-up, the trapezoidal image 142 turns into a square image 145. In other words, by giving the shot of the original 141 a distortion 142 opposite to the distortion to be expected in the display, the distortion occurring in the display is compensated and the result is an image that basically corresponds with the undistorted original 141.

Figures 7A and 7B illustrate another embodiment of a display device 200 according to the present invention, intended for use in a shop or the like. The figures offer a schematic top view of a shop 201, with sidewalls 202, a rear wall 205 and a front side 203, in which a display windowpane 204 and a door 206 are situated. The display device 200 includes a roll-up transparent foil 210 and a display screen 220, which in this example is set up near a sidewall 202, in such a way that this display screen is not visible from the outside.

Figure 7A illustrates a situation in which the shop is open. The foil 210 is rolled up into a roll with a vertical axis, and is situated in its entirety in a foil case 230. This foil case 230 is not essential, but does serve to protect the foil 210. The foil case 230 is represented with a round contour; however, this is not essential either. The display screen 220, situated between the display windowpane 204 and the foil case 230, is switched off. In an embodiment with a projector 115, the projector in question is switched off.

Figure 7B illustrates a situation in which the shop is closed. The foil 210 is stretched between the foil case 230 and an attachment point 240 near the opposite side wall, for instance a vertical pillar or the like. The foil plane is oriented obliquely in the store, with the attachment point 240 closer to the front side of the shop 203 than the foil case 230. The display screen 220 is switched on. It is noted that it is also possible that the foil case 230 is situated closer to the front side of the shop 203 than the attachment point 240; in that case, the display screen 240 is situated between the attachment point 240 and the front side of the shop 203.

In a similar way as explained above, an observer outside the shop 201 will perceive through the foil 210 a virtual image 220' from the display screen 220, and therefore will perceive a virtual image of the objects and/or persons displayed on the display screen 220. This will be typically moving images, perceived between the other objects present in the shop, as a result of which a realistic three-dimensional illusion is created. This illusion may be used as promotional statement: because of the perceived movement, the shop 201, or the display space behind the shop window 204, holds an increased attraction. The illusion may also be used to create the impression that several persons are inside the shop 201, as a result of which the shop is less attractive to burglars.

It will be clear to a person skilled in the art that the invention is not limited to the embodiment examples discussed above, but that various variants and modifications are possible within the protective scope of the invention as defined in the attached claims. As variations, it is possible, for instance, that the said view openings are completely open, but it is also possible that a transparent shield is installed, made of glass for instance.

The foil used can be completely colorless. However, it may be desired that the foil has a certain color to achieve a certain desired color effect.

In addition, embodiments are conceivable in which the active display screen has been replaced by a passive display screen in combination with an image projector. When projecting an image from a projector on a projector screen, the projection may be direct or indirect. This also applies to the optical route between a display screen and a reflecting foil.

Claims

1. Display device for presenting at least one virtual three- dimensional object, including: a case (2; 62) with a first view opening (4; 64); a transparent, thin reflection member (10) with smooth, reflecting surfaces, set up at an angle behind the view opening (4; 64) ; means (20; 66) to generate a light image, set up between the view opening (4; 64) and the reflection member (10).

2. Display device according to claim 1, wherein the means (20; 66) to generate a light image include an active, light- emitting image display device (20; 66).

3. Display device for presenting at least one virtual three- dimensional object, including: a transparent, thin reflection member (10) with smooth reflecting surfaces set up at an angle with respect to the direction of view; an active, light-emitting image display device (20; 66), set up between the view opening (4; 64) and the reflection member (10) .

4. Display device according to any of the preceding claims, with a horizontal direction of view, with the image display device (20) directed according to a plane that is substantially horizontal, and with the reflection member (10) directed according to a plane that is spanned by a horizontal line and a line meeting the horizontal at an angle.

5. Display device according to any of the preceding claims, with a horizontal direction of view, with the image display device (20) directed according to a plane that is substantially vertical, and with the reflection member (10) directed according to a plane that is spanned by a vertical line and a line meeting the vertical at an angle.

6. Display device according to claim 1, with a vertical direction of view, with the image display device (20) directed according to a plane that is substantially vertical, and with the reflection member (10) directed according to a plane that is spanned by a horizontal line and a line meeting the horizontal at a certain angle.

7. Display device according to any of the preceding claims, with the reflection member being a thin, transparent, stretched foil.

8. Display device according to any of the preceding claims, with the image display device (20) being controlled by a control unit (40) that is set up to receive the images to be displayed through a network connection.

9. Display device according to any of the preceding claims, with the image display device (20) being controlled by a control unit (40) that is set up to receive instructions through a network connection and to change an image to be displayed in response to the instructions received.

10. Display device according to any of the preceding claims, and furthermore comprising: a second image display device (76) opposite the first image display device (66); with the two image display devices (66,76) being set up on opposite sides of the reflection member (10) .

11. Display device for presenting at least one virtual three- dimensional object, including: a foil case (230) to be set up in a shop (201) with a rolled- up transparent foil (210) in it with smooth reflecting surfaces; an attachment medium (240) to be set up diagonally across that foil case (230) ; a device (220) to be set up next to the foil case (230) or next to the attachment medium (240) for generating a light image.

12. Display device according to claim 11, wherein the device (220) to generate a light image includes an active, light- emitting image display device (220) .

13. Display device according to claim 11 or 12, with the foil case (230) being set up in a shop (201), with the winding axis of the foil (210) oriented vertically; and with the attachment medium (240) set up in the shop (201) at a distance from the foil case (230); with the foil case (230) and the attachment medium (240) having mutually different distances to a window (204) .

14. Display device according to claim 13, with the image display device (220) set up between the window (204) and the foil case (230) or the attachment medium (240) , whichever is further away from the window (204).

15. Display device for presenting at least one virtual three- dimensional object, including: a transparent, plane projection member (110) , substantially at right angles to a line of sight (106) ; an image projector (115) directed towards the projection member (110) ; with the projection member (110) having such feature so that the projection member (110) can function as projection screen for the images projected by the image projector (115) while at the same time the objects (V) set up behind the projection member (110) can be perceived through the transparent projection member (110) without any noticeable interference.

16. Display device according to claim 15, with the projection member comprising a stretched foil.

17. Display device according to claim 15 or 16, with the projection member (110) having a suitable level of roughness.

18. Display device according to any of claims 15-17, with the projection member (110) having a suitable amount of pigment.

19. Display device according to any of claims 15-18, the image projector (115) being set up between the projection member

(110) and an observer, in such a way that a perceived image is created by reflection via the projection member (110) .

20. Display device according to any of claims 15-18, the projection member (110) being set up between the image projector (115) and an observer, in such a way that a perceived image is created by transmission via the projection member (110) .

21. Display device according to claim 20, with the projection member (110) comprising a display window pane.

22. Method for presenting at least one virtual three- dimensional object, using a device according to any of the preceding claims, wherein a moving image against a dark background is made of a three-dimensional object, which image will be projected or reflected, respectively, by way of the transparent projection member or transparent reflection member, respectively.

23. Method for presenting an image of an original object (141) by way of image projection, wherein a projector (115) projects an image obliquely on a projection plane (110) so that a projection distortion of a beam of light (116) generated by the projector (115) occurs; the method including the step of distorting a shot (142) of the original object (141), with this shot distortion chosen in such a way that it effectively compensates the said projection distortion.