AU2004299885A1 - Viewing screen - Google Patents

Description

German Discount Translations Tax Invoice 5 Wattletree Place Fl : 3 - o o 7 ABN No. DATE INVOIOE NO The Gap o : 9Z 3 /Z -3 61 410 209 252 1/02/2005 2086 Brisbane, QLD 4061 -if USTRALIA INVOICE TO Harry Hahn 5/6 Breaker St Main Beach Q 4217 Customer ABN No. DESCRIPTION QTY TAX TAX AMT AMOUNT Translation, amendment and correction of GST 77.27 772.73 documents GST TOTAL 77.27 TOTAL PRICE INCLUDING GST $85o.oo Viewing Screen Existing projection screens utilise either white surfaces which reflect light evenly over the solid angle or have a preferred reflection direction for the screen surface e.g. through the addition of 5 glass pearls to the surface coating material. Projection screens are also available with preferred reflection directions, which have metallic reflecting screen surfaces that have a parabolic arched surface. A common property of all known projection screens is their relatively limited suitability for projection tasks in bright rooms or projection tasks in broad daylight or other such environments lo with (high) interference light. This is due to the fact that the projected image reaches the observer with insufficient brightness in comparison to the surrounding brightness or because interference light reflected from the screen (e.g. ceiling light) sheds its rays over the projected image to too great an extent. In addition, interference light is normally reflected from the surface of existing projection screens diffusely in the direction of the observer in a manner whereby the 15 strength of reflection is similar to that of the projected image, which considerably decreases the contrast in the projected image when the room is under bright light or there is strong external brightness. Because of this, the projected image appears flat (lacking in contrast) and colourless. The parabolically or elliptically arched screens or the directed reflection glass pearl projection 2o screens are more suitable for projection tasks in brightly lit rooms but these types of screens also have the disadvantage of poor lateral visibility because the projected image is only reflected in a small horizontal solid angle or reflection angle. Therefore the aim of this invention was to develop a new kind of projection screen (viewing screen) which can be used above all in brightly lit rooms (e.g. conference rooms) with ceiling 5 light and those affected by broad daylight, without having to accept strong contrast or brightness losses in the images projected. A further aim was to create a projection screen in which the projected image is reflected in a large horizontal as well as a small vertical solid angle in order to achieve high light amplification. Here an additional aim was to be able to define exactly the horizontal and the vertical solid o angle in which the projected image is reflected. An additional aim was to create a viewing screen, which allows extremely precise definition of the complete 3-dimensional space into which the image is projected. A projection screen (viewing screen) according to this invention is shown in FIG.1 with the aid of an example. The viewing screen 1 (invention variant 1 as shown) consists of a spherical, ellipsoidal or s parabolical arched surface with a reflecting surface consisting of a micro-mirror surface structure 2 in accordance with the invention.

2 Fig.2: The micro-mirror surface structure 2 in accordance with the invention consists of small mirrors (micro mirrors) with a concave or convex shape that are arranged in a predetermined pattern, such that they lie side by side on the viewing screen surface. 6_L Preferably the pattern in accordance with the invention is a pattern with a honeycomb-lattice-like 5 structure 3. Here the micro-mirror surface structure 2 can be made up of either individual micro mirrors or a continuous medium into which the micro mirrors are formed in a defined manner. The preferred mirror surface of the micro mirrors in accordance with the invention is a shiny, metallic surface. However micro mirrors with a slightly dull metallic mirror surface can also be used to slightly io reduce the strong mirror effect of the micro mirrors. The size of the micro mirrors has to be chosen so that it is precisely as small as required, such that the pixel-dependent image sharpness of the most common projectors can be fully exploited or in such a way that the observers do not feel that they are disturbed by a "lattice point effect". As depending on the application (e.g. home theatre or stadium screen) this can allow for very 15 different maximum micro mirror sizes, the possible maximum dimensions of micro mirrors can in practice be approximately in the range 0.5-30mm. The micro mirrors used in the micro mirror structure in accordance with the invention have a defined elliptical outline shape 4, a defined oval outline shape 65, a defined stretched hexagonal outline shape 5, or an outline shape which corresponds with a defined polygon ( line) which approximates to an ellipse or an oval 66 (e.g. 20 a defined stretched hexagon, rectangle, octagon, decagon, dodecagon etc). This means that the higher the number of corners of the polygon, the better the approximation. According to the invention, the preferred outline shapes are the defined elliptical outline shape 4, the defined oval outline shape 65, or the defined hexagonal outline shape 5. The three-dimensional shape of the mirror surface of the micro mirrors corresponds here, depending on the outline shape selected, 25 exactly or almost exactly with the inner or outer surface (depending on the use of concave or convex mirrors) of a cap-like part, cut out of a defined hollow (or thin-walled) ellipsoid, ovaloid, rotation ellipsoid or rotation ovaloid 71. FIG 2: In accordance with the invention, the micro mirrors are - in relation to a vertically mounted viewing screen (viewing screen in the user position) - orientated on the screen surface 30 with their long half-axis precisely in the direction of the screen height or in a vertical (Y) direction and with their short half-axis exactly in the direction of the screen width or in the horizontal (X) direction, if the screen surface is located in the user position. FIG 2: The micro mirrors used in accordance with the invention and oriented with their long half-axis in the vertical direction (or in the direction of the screen height) have the property of being able to reflect the incoming 35 projector light 6 to the viewers in the form of an elliptical or oval light cone 7 or in the form of an approximately elliptical or approximately oval light cone 8 (in the case of the polygonal outline shape which approximates to an oval or an ellipse). The long half-axis of the reflected elliptical J or ellipse-like light cone is orientated in a horizontal direction and the short half-axis is orientated in a vertical direction. Fig 3: The micro mirrors used in the surface structure described in accordance with the invention, with the long mirror half-axis 9 orientated in the vertical (Y) direction and the short 5 mirror half-axis 10 orientated in the horizontal direction have a slight vertical curvature 11 (or in other words a large vertical curvature radius) and a strong horizontal curvature 12 (or in other words a small horizontal curvature radius). The vertical reflection angle 13 ( y ) of the micro mirror is substantially smaller than the horizontal reflection angle 14 ( x,) which causes high light amplification but still allows for a big horizontal reflection angle of the viewing screen. 10 Here the described curvature of the micro mirrors can either be a (concave) curvature inward (concave mirror) or a (convex) curvature outward (convex mirror). The ratio between the vertical reflection angle 13 and the horizontal reflection angle 14 of the micro mirrors directly depends on the ratio between the short mirror half-axis 10 and the long mirror half-axis 9 of the micro mirrors. 15 FIG.2: The shape of the reflected elliptical or oval light cones 7 or the shape of the approximately elliptical or approximately oval light cones 8 (in the case of a polygonal outline shape of the micro mirrors) is consequently able to be defined in a precise way by the ratio of the long mirror half-axis 9 of the micro mirrors to their short mirror half-axis 10 as well as by the level of the curvature of the micro mirrors and the exact outline shape of the micro mirrors. 2o As a result, with the viewing screen in accordance with the invention with the described micro mirror surface structure, an exactly defined reflection of the projected image can be achieved. Furthermore, the space in which the image is reflected can be defined in a very precise way. The following applies here : 25 - The stronger the curvature of the micro mirrors (concave or convex mirrors), the bigger the vertical and horizontal reflection angle with which the incident projector light is reflected. - The bigger the ratio of the long mirror half-axis to the short mirror half-axis of the micro 30 mirrors, the bigger the ratio between the horizontal reflection angle and the vertical reflection angle of the light reflected from the micro mirrors. FIG.819: Because of this it is possible to achieve viewing screens where the vertical reflection angle of the viewing screen 16 is substantially smaller than the horizontal reflection angle of the 35 viewing screen 15 so that a high light amplification effect is produced without the limitation of a horizontal reflection angle that is too small (see variant examples in Fig.8 and Fig.9).

4 To attain the desired most optimal reflective properties from the viewing screen in accordance with the invention, the micro mirrors of the micro-mirror surface structure, which preferably in accordance with the invention has a honeycomb-lattice-like shape, must have a precisely defined spatial orientation on the viewing screen surface, corresponding to the planned size of 5 the projection zone 17 (=auditorium). Therefore it is the aim to orientate all micro mirrors in such a way that their mirror normals (optical axes) all essentially intersect the centre normal 26 of the viewing screen in a predetermined distance at a predetermined point of intersection 18 or at a predetermined straight line of intersection, which has a predetermined length, or that the optical axes of all micro mirrors intersect a narrow space around a predetermined point on the centre 10 normal of the viewing screen 26. The reflection behavior of the viewing screen, as well as the attainment of the most optimal shape of the projection zone 17 with the highest possible light amplification essentially depends on the defined position of this point of intersection or the straight line of intersection or section area. In addition, this ensures that the loss space 19 in which not all light cones reflected through the micro mirrors overlay each other, is minimized, 15 whereby the projector performance can be utilized to the fullest. This is because only in the spatial overlaying zone (= projection zone 17) in which the reflected elliptical or ellipse-like light cones emanating from all of the micro mirrors overlay each other can the complete projected image be seen. On condition that the projector is positioned on the centre-normal of the viewing screen 26, then the most optimal area of the projection zone is located in a narrow vertical area 20 20 parallel to the screen which goes through the projection zone near the defined point of intersection 18, because the light cones reflected from all micro mirrors overlay each other here almost up to 100%. In the most optimal case, this area is very narrow and it lies, in relation to the vertical and horizontal reflection behavior of the screen (see the horizontal and vertical section through the projection zone - e.g. FIG. 8), approximately on the same plane which, for 25 example, can be optimised even more through an exact definition of the curvature of the screen (in variant 1) or in other words through an exact definition of the straight line of intersection of the optical axes of all micro mirrors (e.g. through a defined ellipsoidal curvature of the screen). According to the invention, 3 variants were developed to achieve a defined spatial orientation of the micro mirrors, in such a way that their optical axes intersect each other on the centre-normal 30 of the viewing screen at a common point of intersection or on a straight line of intersection of predetermined length, or that their optical axes intersect in a predetermined narrow spatial area around the centre-normal of the screen. 35 5 Description of the 3 variants: Variant 1 according to the invention: 5 FIG.8: Spatial orientation of the micro mirrors by using a defined spherical, ellipsoidal or parabolically curved viewing screen 21. Here the following definitions apply: The optical axis of each micro mirror stands perpendicular to the curved surface of the viewing screen. As a result, the optical axes of all micro mirrors (e.g. in the case of a 10 spherical curvature of the viewing screen) intersect at the sphere centre point 22 of the spherically curved viewing screen surface. In the case of a defined ellipsoidal curvature of the viewing screen, the optical axes of all the micro mirrors intersect on a straight line of intersection with a defined length, which lies on the centre-normal of the screen (or in other words on the surface normal of the centre of the screen). 15 The length of this straight line of intersection depends on the ellipsoidal curvature. With an ellipsoid-curved viewing screen, the reflection behavior of the viewing screen and with it the most optimal area of the projection zone 20 can be defined even more precisely than with the spherical curvature. FIG.8: For the purposes of simplification of the diagram, in this variant example of a 20 spherically curved viewing screen 21, it was assumed that the projector was positioned at the sphere centre point 22 of the spherically curved viewing screen. If the projector is positioned outside the sphere centre point 22 on the centre-normal of the screen 26, then the vertical and horizontal reflection angles of the viewing screen change, which has to be taken into consideration in the design of the screen through a corresponding choice of the 25 reflection angles of the micro mirrors. Positioning the projector outside the centre-normal 26 (e.g. if the projector is mounted in the ceiling) can to a certain extent be corrected well through slight swivelling of the screen around its horizontal central axis. Variant 2 according to the invention : 30 FIG.6 I 9: Dividing of a plane viewing screen 23 into a defined number of sectors 24, with a different spatial orientation 25 of the micro mirrors in each sector relative to the centre normal of the screen 26. Each sector has a specially defined micro-mirror surface structure 2, which depends on its 35 position on the viewing screen. In each sector, the optical axes of the micro mirrors have a uniform spatial orientation 27.

FIG.9: The spatial orientation of the micro mirrors within the individual sectors is selected here in such a way that the optical axes of the micro mirrors lying in the centre of each sector intersect in a predetermined point of intersection 18 or on a straight line of intersection with a defined length, whereby the point of intersection or the straight line of S intersection lies at a certain distance from the plane viewing screen 23 on the surface normal 26. The optical axes of the micro mirrors, which do not lie in the sector centre intersect a predefined narrow spatial area around the above-mentioned point of intersection 18 or around the straight line of intersection. 10 FIG.6: The spatial orientation of the micro mirrors, or to put it better, the angle of inclination of the optical axes of the micro mirrors is most strongly pronounced in this screen variant in the corner sectors 28 of the screen. Both the vertical and the horizontal inclination of the optical axes of the micro mirrors towards the screen normal is greatest in the corner sectors 28. 5 FIG.7 shows a three-dimensional drawing of a small partial section of a corner sector of such kind. The concave micro mirrors have a hexagonal outline shape stretched in the direction of the screen height. FIG.6: In the sectors which are located on the horizontal (X) central axis or on the vertical (Y) central axis of the viewing screen, the micro mirrors are in each case only inclined 0 towards the centre-normal of the screen in a horizontal or in a vertical direction depending on their position. Only in the sector in the viewing screen centre 29 are the optical axes of the micro mirrors vertical to the screen surface and they therefore have no angle of inclination there towards the centre-normal of the screen. FIG.5: The division of the plane viewing screen 23 into sectors can be made here in 5 different ways. The division that is most preferred here is into square or rectangular sectors 30 or a concentric division into circular-shaped, ellipse-shaped or oval-shaped ring-segments 31, or a concentric division into polygon-shaped ring-segments 32 of different size, which begin at the centre of the viewing screen. Depending upon the shape of the ring segments, the sector located on the viewing screen centre has a circular, S elliptical, oval or polygonal shape. See examples in FIG. 5 Here the following applies: The finer the division of the viewing screen surface into defined sectors with different spatial orientation or in other words different angle alignments of the optical axes of the micro mirror structure, the more optimally the reflection behavior of the viewing screen can be designed and the smaller is the loss space 19 of the unusable reflected projector light (see FIG. 9). FIG.9: In the variant example depicted, a plane viewing screen 23 can be seen which was divided into 25 rectangular sectors 30 of the same size. To simplify the diagram, it was '? / _'/ 7 assumed in this example that the projector was positioned at the defined point of intersection 18. Here the defined point of intersection 18 is the point of intersection of the optical axes of the micro mirrors, which are located at the centres of the sectors. The projection zone 17 in which the light cones reflected from all the micro mirrors overlay 5 each other and in which the complete projected image can be seen, is shown in the hatched sections depicted. For the micro mirror structure, in this variant of the screen in accordance with the invention, concave mirrors are preferred; this is because, when concave mirrors are used, the reflected light first converges at a focal point before it starts to diffuse. 10 FIG.7 : Therefore concave mirrors are advantageous in this variant because in the case of a stair-like displacement 33 of the micro mirrors that occurs when micro mirrors are brought in obliquely to the screen surface, partial covering of the reflected light through the stair-like displacement can be avoided. 15 Variant 3 according to the invention: , FIG.4: The third possibility is the precise spatial orientation of every single micro mirror on a plane viewing screen 23 corresponding to its position on the viewing screen surface. The aim here is to orientate the optical axes of all micro mirrors of the micro-mirror surface 20 structure 2 in such a way that they intersect at a predefined point of intersection 18 or straight line of intersection of a defined length. This defined point of intersection 18 or the straight line of intersection lies at a certain distance from the screen on its surface-normal 26.The projection zone 17 created hereby is nearly identical to that of the projection zone 17 of a viewing screen according to variant 1 of the invention (see variant example FIG. 8) where also every single 25 micro mirror has a different spatial orientation, corresponding to its position on the (in this case) curved surface. FIG.10: Here, as a comparison, the poor reflection behavior of a viewing screen is shown in which the optical axes of the micro mirrors are not orientated towards a common point of intersection or a common straight line of intersection. 30 In this example the optical axes of the micro mirrors are all parallel to one another. It can be clearly seen that the spatial overlaying zone (= projection zone 17) in which the light cones emanating from all the micro mirrors overlay each other, is much smaller than in variants 1-3 described in accordance with the invention (Fig.8 / Fig.9). 35 Of the 3 described variants 1-3 in accordance with the invention, variant 1 and 2 are preferred. Here variant 1 is the preferred method in accordance with the invention for plate-shaped curved viewing screens, whereas variant 2 is the preferred method in accordance with the invention for foil-like or screen-like projection walls (which can be rolled up).

8 With variant 2 the optical axes of the micro mirrors can only be approximately made to intersect in a defined spatial area whose centre lies on the screen-normal and so the reflection behavior or the projection zone 17 of the viewing screen cannot be designed as optimally as when variant 1 is used. However variant 2 is applicable for the highly economical creation of plane 5 foil-like or screen-like projection screens (which can be rolled up). For example, through the application of a press tool with special embossing plates or embossing rollers, the complex micro mirror surface structure of variant 2 that is divided up into sectors can be embossed in a corresponding foil-like or screen-like projection screens in a very cost-effective way. After that only the application of a mirror coating (e.g. through vacuum metallization) and possibly of an 10 additional protective layer is necessary. Curved viewing screens in accordance with variant 1 can, for example, be produced with a two part form-press and embossing tool. Here it would be possible in the same working cycle to give the viewing screen the desired curvature and the desired micro mirror surface structure. 15 The described variants 1-3 in accordance with the invention are to the greatest possible extent insensitive to interference light sources, especially if the vertical reflection angle of the viewing screen was defined such that it was appropriately small. If we select for the micro mirrors of the viewing screen the smallest possible vertical reflection angle, then many interference light reflections can be almost completely avoided from the outset. FIG 11. shows a cross-section 20 view of a corresponding viewing screen in accordance with the invention with a small vertical reflection angle. The viewing screen shown has the same reflection properties here as the viewing screen depicted in the variant example in FIG. 8. In the depicted vertical cross-section through the centre of the projection zone 17 of the screen (according to the variant example in FIG.8), an interference light source 34 and its interference 25 reflections on two micro mirrors 35 and 36 which are located on the edges of the viewing screen is shown. The position of the interference light source was chosen in such a way that from the micro mirrors 35 (above) and 36 (below) just no interference light is reflected into the defined projection zone 17 (=auditorium). From the constructed interference light reflections (light cones) 37 and 38 that emanate from the 30 micro mirrors 35 (above) and 36 (below) located on the viewing screen edges, it can be seen that interference light sources located within the critical angle area 40 can cause disturbing reflections which are partly reflected into the projection zone 17, whereas interference light sources located within the uncritical angle area 39 only cause interference light reflections which are reflected past the projection zone 17 and therefore cannot reach the viewers within 35 the defined projection zone. To achieve the biggest possible uncritical angle area 39 without causing disturbing reflections in the projection zone, the smallest possible vertical reflection angle 13 of the micro mirrors must therefore essentially be achieved (at a given projector position and screen position).

9 In this connection it can also be seen that the smaller the vertical reflection angle of the micro mirrors, the better the contrast of the screen in accordance with the invention, as the interference light effects decrease more and more with a decreasing vertical reflection angle of the micro mirrors. 5 FIG.12: (cross-section): Also interesting is the achievement of an infinitely variable curvature of each micro mirror used. Through this the horizontal and the vertical reflection angles of the micro mirrors used and with it also the horizontal and the vertical reflection angle of the viewing screen can (simultaneously) be changed infinitely variable. 1o The change in the curvature of the micro mirrors required for this can be made with a device for the generation of an electrostatic or electromagnetic field 67 which is in active conjunction with the micro mirrors. For this the micro mirrors are made in such a way that through change in the electrostatic or electromagnetic field, the curvature of the micro mirrors is changed. 15 FIG.12: The change in the curvature of the micro mirrors can also be achieved through a predetermined change in the pressure of a fluid 45 which is locked in a chamber and which is in contact with the micro mirrors. The change in pressure is achieved here through a device for the generation of a predetermined pressure 46, which is in active conjunction with the fluid 45 and 20 the described chamber through a kind of channelling-system. The micro mirrors here are made in such a way that a change in the pressure of the fluid causes a change in the curvature of the micro mirrors. In the following, the design of a viewing screen (device) of such kind is described. On this screen the change in the curvature of the micro mirrors is made by a pressure change of air in a 25 gasproof frame construction 42. The surface of the viewing screen is made of an elastic, metallic, reflecting (metal-coated) foil 43, which lies on a lattice with defined openings, which forms the front side of the frame construction. Here the foil is connected in a gasproof manner with the frame construction. The outline shape of the openings in the lattice described is equivalent to the desired outline shape of the micro 30 mirrors. Preferred here is a honeycomb-shaped lattice 44 and the preferred outline shape of a honeycomb is a predetermined hexagon 70, which is stretched in the direction of the viewing screen height. This honeycomb-shaped lattice 44, which forms the front side of the frame construction 42 is supported by means of a substructure 69 (not shown). The substructure 69 can be plane or it 35 can have a predetermined curvature. If a curved substructure is used, then a curved viewing screen according to variant 1 (FIG.8) can be created.

1u By generating an underpressure 45 inside the gasproof frame construction 42, the metallic reflecting foil 43 is stretched into the honeycomb-shaped lattice 44, so forming a micro mirror surface structure 2 in which all the micro mirrors have almost the same curvature, the same outline shape and the same dimensions. 5 The whole viewing screen surface assumes here the predetermined shape of the substructure (e.g. a defined spherical curvature). By changing the underpressure 45 inside the frame construction 42 through a device for the generation of a predetermined pressure 46 (underpressure), the horizontal 15 and vertical reflection angle 16 of the viewing screen can simultaneously be adjusted indefinitely variable through the change in the vertical 13 and the iO horizontal reflection angle 14 of the micro mirrors which is caused by this. Because of this, the light amplification as well as the contrast and the susceptibility to interference light of the viewing screen can also be adjusted indefinitely variable. The possible adjustment range of the vertical and horizontal reflection angle of this viewing screen essentially depends here on the elastic material properties of the foil used. 15 Additionally, the described viewing screen can also have an adjustable viewing screen curvature, which for example can be achieved through a distortable elastic plate that is applied as a substructure 69 for the described lattice that is used for the production of the micro mirror surface structure. The elastic plate can be distorted through the effects of different forces (e.g. through an electrostatic, electromagnetic or mechanical force). 2o Through an adjustable viewing screen curvature, the distance of the focal point or focal area - to which the optical axes of the micro mirrors are orientated - can be moved along the centre normal of the viewing screen, which allows the projection zone 17 to become spatially adjustable. Together with the adjustability of the reflection angles of the micro mirrors, the reflection behavior of this viewing screen (especially the light amplification) can be adjusted in a 5 controlled manner within a wide range. To protect this adjustable micro mirror surface structure from being destroyed, the addition of a transparent plate or cover can be fixed directly in front of the micro mirror surface structure at a short distance from the surface. o FIG.13: This drawing describes a simple process for the production of a viewing screen according to variant 1 in accordance with the invention (see also FIG. 8). For this process, the same device as described in FIG.12 is used. Here, the device described in FIG. 12 serves as a kind of vacuum stretching tool with which the micro mirror surface can be created for a viewing screen according to FIG. 8. 5 The complete production process of a viewing screen according to variant 1 (FIG. 8) is now described briefly with the following production steps (production steps A-G): 11 Production Step A: An elastic metallic reflecting (vacuum metallized ) foil 43 is placed on the honeycomb-shaped lattice 44 and lightly drawn out to the edges of the gasproof frame construction 42. On the edges of the gasproof frame construction, the foil is then attached so that it is gasproof e.g. with S a sealant glue 47 and held in position with slight tension. Production Step B: After the metallic reflecting foil 43 is correctly brought into position on the frame construction 42 and fixed with slight tension, an underpressure 45 is generated inside the gasproof frame o construction 42 by means of a device to generate a predetermined pressure 46. In this way, the metallic reflecting foil 43 is stretched into the lattice openings of the honeycomb-shaped lattice 44, so forming a micro mirror surface structure, as described in FIG.12. Production Step C: 5 After the correct curvature of the micro mirrors is achieved in the gasproof frame construction 42 by setting a certain underpressure, the fixing of the foil with the curvatures and micro mirrors shaped in the individual lattice openings starts. During this process this underpressure is kept constant. Here the side of the foil 48 which is structured through the underpressure and which is orientated outwards (towards the ambient pressure) is sprayed with a material that hardens e.g. o with a fast-hardening resin 49. This can for example be done with automatic spray equipment 51. After that, a drying process using hot air can be added for faster hardening of the resin (not shown). Drawing D: 5 This drawing shows the foil structured through underpressure, with the fixed micro mirror surface structure 50. Production Step E / F: In these production steps, the foil with the fixed micro mirror surface structure 50 is fastened to 0 a support plate 55. This is done in a form press tool with press surfaces, which consists of a form press tool top 52 and a form press tool base 53. For the production of a viewing screen in accordance with variant 1 (FIG.8), preferably a form press tool with defined curved press surfaces and a support plate 55 with a predetermined curvature is used. Here, the first step is to spread a layer of even thickness of an adhesive substance 54 on the concave curved side of 5 the support plate 55. After that, the foil with the fixed micro mirror surface structure 50 is joined, by pressing together the form press tool top 52 and form press tool base 53. Drawing F shows a cross-section through the closed form press tool 57.

12 The joining process is carried out here with only slight pressure. The hardening process of the adhesive layer can be accelerated through a heated form press tool. The press surface of the press tool top 52 should also be somewhat elastic (e.g. rubber coated) to avoid damage to the micro mirror structure during the pressing process. 5 Production Step G: After the adhesive substance (adhesive layer) 54 is hardened, the finished viewing screen can be taken out of the form press tool. The finished viewing screen 56 is shown in the drawing. A non-metallized foil (e.g. a transparent foil) can also be used in the described production 0 process instead of a vacuum-metallized foil. In this case, the mirror-coating or better metal coating of the micro mirror surface structure would then be carried out after production step C or G. In a similar manner to the production process described, a production process is also conceivable that works with overpressure instead of underpressure. 5 The process described in FIG.13 can also be used for the production of so-called "prototype viewing screens" and can therefore serve as a basis for a further production process (3 production steps A - C). This process is not diagrammatically represented. Production Step A: o With the production process described in FIG.13 (production steps A-G), a so-called "prototype viewing screen" is produced, as described first. Production Step B: The "prototype viewing screen" produced in this way is then used as a form model (tool) from 5 which embossing plates 58 (not shown) are produced. Production Step C: The embossing plates 58 produced are then used in embossing tools for the mass production of viewing screens. Besides press tools with embossing plates, press tools with embossing Strollers 59 can also be used. For this, the embossing plates 58 produced are transformed into embossing rollers e.g. by fixing them on the peripheral surface of suitable rollers. With these embossing tools created in this way, the micro mirror surface structure of the embossing plates or embossing rollers 60 can be embossed in a fast production process e.g. into thermo-plastic plates or thermo-plastic foils. SThese embossed plates or foils which then have the same micro mirror surface structure as the "prototype viewing screen" then only have to be coated, for example by means of a vacuum metallization process 61 with a shining surface, through which the micro mirror surface structure 13 then attains its metallic reflecting surface 62. The metal-coated viewing screen plates or metal-coated viewing screen foils 63 created in this way can have additional coatings 64 depending on their use (e.g. protective coatings or coatings with optical properties). 5 The advantages of the viewing screen according to this invention are in particular as follows: The mirror-like surface of the micro mirror structure reflects the incoming projector light almost without losses. 10 The vertical reflection angle and the horizontal reflection angle of the viewing screen can in principle be defined very precisely through the exact definability of the reflection behavior of the micro mirror structure in accordance with the invention. As a result, almost every conceivable light amplification of the projected image is possible, though at the cost of the reflection angles. 15 The three-dimensional projection zone into which the projected image is reflected can be defined precisely through the combination of the predetermined reflection behavior of the micro mirrors and the defined spatial orientation of the optical axes of the micro mirrors. With a viewing screen according to the variant described in FIG.12, the entire reflection behavior of this o viewing screen can even be flexibly set in a wide range at any time. The spatial reflection behavior of the viewing screen can be specially designed for every special application in an optimal manner in order to achieve the maximum possible light amplification. 5 With a plane viewing screen corresponding to variant 2 or 3 in accordance to the invention, a foil-like or screen-like projection wall with a high light amplification can be achieved. This has not been previously possible with plane and rollable viewing screens. The vertical reflection angle of the viewing screen in accordance with the invention can be 0 chosen to be very small, which is highly advantageous because considerable light amplification can be achieved without restricting the horizontal reflection angle of the viewing screen, which is much more important for the viewers because the eye heights of all viewers lie approximately on the same horizontal plane. This is also because interference light, particularly the reflection from ceiling lights in the direction of the viewers, can be prevented to a large extent through a Small vertical reflection angle, which leads to a considerable increase in contrast in the screen.

14 The structure of the viewing screen is relatively simple because the reflection of the projected image is only effected through a metal-coated structured surface. Because of this the viewing screen can be mass-produced in large numbers in a very 5 economical way e.g. through the use of an embossing tool ( press tool with embossing-plates or embossing-rollers). The range of application of the viewing screen with the defined micro mirror surface structure in accordance with the invention is very versatile: 10 The viewing screen in accordance with the invention is most suited to image projection in brightly lit rooms or rooms affected by broad daylight or interference light. If the vertical reflection angle of the micro mirrors used is selected so that it is as small as possible, very high light amplifications, a very high contrast and a very small susceptibility to interference light are 15 attainable, which makes the viewing screen in accordance with the invention (in all variants) particularly suitable for this kind of application. A further interesting area of application of the viewing screen in accordance with the invention is the home theatre field. For this field the viewing screen variant 2 in accordance with the 20 invention seems to be especially well suited (plane viewing screen with a micro mirror surface structure divided into defined sectors). With this variant, plane foil-like or screen-like projection screens (which can be rolled up) with a high light amplification are possible, which can be mass-produced economically, for example through the use of an embossing technique und subsequent metal-coating ( vacuum-metallization) 25 An interesting area of application would also be the use of the viewing screen in accordance with the invention in a very small variant with a very fine micro mirror surface structure and very small micro mirror dimensions e.g. for projection purposes or generally for a defined-directed, fixed or adjustable diversion of light in the most varied of optical devices or multi media 30 machines. A further interesting option for application of the viewing screen in accordance with the invention would also be its use for lighting purposes or in general for the diversion of light. Here the viewing screen in accordance with the invention can, instead of using a video projector, be 35 exposed to rays from the most varied of light sources so that the viewing screen transforms the incoming light in each case almost without loss into a defined-directed bundle of light rays with a defined vertical and horizontal reflection angle.

This defined-directed bundle of light rays with the defined reflection angle can then be used, for example, for lighting tasks. Here the viewing screen in accordance with the invention can, depending on the application, also reach quite big dimensions (length x width), with a substantially enlarged micro mirror structure (the micro mirror structure then becomes the 5 reflection mirror structure!) The screen can then even be used for very precise and purposeful lighting or for diversion of light if a viewing screen variant as described in FIG.12 is used, because of the infinitely variable adjustability of the reflection angles of the micro mirrors and also the adjustability of the curvature of the screen. The viewing screen in accordance with the invention, can, for example, be used in this way for the cost effective large-scale lighting of dark o10 areas of buildings by means of sunlight or for the lighting of rooms of a building, which are deep inside by means of sunlight. If the screen is additionally equipped here with automatic swivel drives on one or more axes, the screen can be orientated very precisely to a particular source of light (e.g. the sun). The orientation of the screen towards the source of light can be automated, for example, with the 15 help of control electronic and light sensitive sensors. In this way, the screen can automatically follow a moving source of light (e.g. the sun). In this way the screen can also be used, for example, for defined orientated diversion of sunlight in solar power plants, e.g. in a solar tower plant or generally in a solar power plant with concentration mirrors (e.g. a concentration mirror solar power plant in an earth-orbit). In these applications, the screen described can assume 20 quite enormous dimensions with micro mirrors (or even better, with reflection mirrors!), which can reach dimensions of several meters ! Furthermore, the viewing screen in accordance with the invention with a defined micro mirror surface structure can also be used as an advertizing board or as an information board (e.g. in 25 the road or railway traffic ). If on the micro mirror surface structure of the viewing screen, a coloured metallic reflecting image is put on in a thin layer (e.g. vacuum-metallized on it), then this coloured image can be seen very brightly if the screen is illuminated with a bright white light from a particular distance and if the viewer himself is located in the projection zone of the screen that is reflected back. 30 If the advertising board or information board described is orientated in the appropriate direction e.g. when used in the road and rail traffic, in relation to the oncoming vehicles (with switched on headlights!), then an image, symbol or text which appears almost self-illuminating can be created for the passenger in the vehicle, as the screen reflects the image lit up by the headlights back to the vehicle in a concentrated manner. 5

Claims (35)

1. A viewing screen having a viewing screen surface to achieve bright reflection of an image which is projected onto the viewing screen, the viewing screen surface 5 comprising micro mirrors being arranged such that they lie side by side on the screen surface to create a reflected image, the micro mirrors being either concave or convex mirrors and all micro mirrors of the viewing screen surface or all micro mirrors of at least one partial area of the scren surface having substantially the same outline shape. 10

2. A viewing screen according to claim 1, wherein all the micro mirrors of the screen surface or all the micro mirrors of at least one partial area of the screen surface have substantially the same predetermined curvature. 15

3. A viewing screen according to claim 1 or claim 2, wherein the micro mirrors of the screen surface are arranged in a predetermined manner side by side on the screen surface in such a way that the remaining area between the individual micro mirrors is minimal. 20

4. A viewing screen according to one of the preceding claims, wherein the micro mirrors have a longish outline shape, which is essentially equivalent to a predetermined ellipse (4) or a predetermined oval (65) or a predetermined polygonal line approximating an ellipse or an oval (66). 5

5. A viewing screen according to claim 4, wherein the micro mirrors are arranged on the screen surface in such a way that their respective long mirror half-axis (9) is orientated in the direction of the screen height or the vertical direction, if the viewing screen is located in the user position and that their respective short mirror half-axis (10) is orientated in the direction of the screen width or the horizontal 0 direction, if the viewing screen is located in the user position.

6. A viewing screen according to one of the preceding claims, wherein the micro mirrors are arranged on the screen in such a way that the optical axes of the micro mirrors have a predetermined spatial orientation.

7. A viewing screen according to claim 6, wherein the micro mirrors are arranged on the screen in such a way that the optical axes of all micro mirrors essentially intersect the centre normal (26) of the viewing screen at a predetermined point (18) of intersection or substantially at a predetermined straight line of intersection, which has a predetermined length, or that the optical axes of all the micro mirrors essentially intersect a narrow space around a predetermined point on the centre normal of the viewing screen (26).

8. A viewing screen according to claim 6 or claim 7, wherein the viewing screen surface has a curvature (21), and wherein the micro mirrors are arranged on the screen surface in such a way that the optical axes of the micro mirrors are perpendicular to the viewing screen surface.

9. A viewing screen according to claim 8, wherein the viewing screen surface has a spherical curvature. II

10.A viewing screen according to claim 8, wherein the viewing screen has a paraboloidal curvature.

11. A viewing screen according to claim 8, wherein the viewing screen has an 5 ellipsoidal curvature.

12. A viewing screen according to one of the preceding claims, wherein the viewing screen surface is divided into at least two sectors, the micro mirrors being arranged on the screen surface in such a way that the optical axes of the micro 10 mirrors of each sector (24) have a uniform spatial orientation (27).

13. A viewing screen according to claim 12, wherein the micro mirrors are arranged on the screen surface in such a way that the optical axes of the micro mirrors, which are located in the centers of the sectors, essentially intersect the viewing 15 screen centre-normal (26) at a point of intersection (18) or on a straight line of intersection which is located at the viewing screen centre-normal (26) at a predetermined distance in front of the screen surface.

14.A viewing screen according to claim 12 or claim 13, wherein the division of the 20 screen surface into sectors is a division into quadratic or rectangular sectors (30).

15. A viewing screen according to claim 12 or claim 13, wherein the division of the viewing screen surface into sections is a division into concentric rings of circular, elliptical, oval or polygonal shape, the centre of which are at the centre of the 6 screen, wherein the sector positioned in the screen centre has a circular, elliptical or oval shape, respectively, or a polygonal shape, which is similar to an ellipse or an oval, wherein the ring shaped sectors surrounding the sector in the centre of the screen further are divided into several sectors representing predetermined segments of the rings (31, 32), and wherein the longitudinal half-axis of the _0 sector located in the centre of the screen surface is orientated along the direction of the screen width.

16.A viewing screen according to claim 6, wherein all the micro mirrors are arranged on the surface of a substantially plane viewing screen (23) in such a way that the 5 optical axes of all the micro mirrors intersect the centre-normal (26) of the viewing screen substantially at a point of intersection (18) or substantially on a straight line of intersection, wherein the point of intersection and the straight line of intersection are located at a predetermined distance in front of the screen surface on the centre-normal (26).

17.A viewing screen according to one of the claims 1 to 11 or claim 16, wherein all the micro mirrors essentially have identical dimensions.

18.A viewing screen according to one of the claims 12 to 15, wherein all the micro mirrors of one sector (24) essentially have identical dimensions.

19.A viewing screen according to one of the claims 4 to 18, wherein the three dimensional shape of the reflecting surface of the micro mirrors essentially is equivalent to the inner or outer surface of a cap-like part, cut out of a predetermined hollow ellipsoid, ovaloid, rotation ellipsoid or rotation ovaloid (71).

20. A viewing screen according to one of the preceding claims, wherein the micro mirrors are arranged in a predetermined pattern (3) on the screen surface.

21.A viewing screen according to claim 20, wherein the outline shape of the micro 5 mirrors is a predetermined hexagon (5), which is stretched in the direction of the screen height, or a predetermined ellipse (4).

22.A viewing screen according to one of the preceding claims, wherein the viewing screen is made in such a way that the curvature of the micro mirrors (11,12) is 10 able to be increased or decreased in an infinitely variable manner, in order to change the horizontal and the vertical reflection angles (13,14) of the micro mirrors.

23.A viewing screen in according to claim 22, wherein the viewing screen comprises 15 a device for generation of an electrostatic or electromagnetic field (67) which is in active conjunction with the micro mirrors, the micro mirrors being made in such a way that the curvature of the micro mirrors is changed by changing the electrostatic or electromagnetic field. 20

24.A viewing screen according to claim 22, wherein the viewing screen comprises at least one chamber and a device for the generation of a predetermined pressure (46), which device is in active conjunction with the chamber, and the micro mirrors being made in such a way that the curvature of the micro mirrors changes when the pressure inside the chamber is changed.

25.A viewing screen according to claim 24, wherein the viewing screen comprises a channelling system which contains a fluid (45), the channelling system being made in such a way that the device for the generation of a predetermined pressure (46) is in active conjunction with the chamber by means of the fluid (45) 3o in such a way that a predetermined pressure can be generated in the chamber.

26.A viewing screen according to claim 25, wherein the surface of the viewing screen including the micro mirrors is created by an elastic metallically reflecting foil (43), which lies gasproof on a lattice (44) forming the front side of a gasproof 5 frame construction (42), wherein the lattice is supported by a substructure (69), which is a part of the frame construction and which is either plane or has a curvature, and wherein the lattice (44) has openings with outline shapes, which correspond to the outline shape of the micro mirrors. 0

27. A viewing screen according to one of the preceding claims, wherein the lattice is a honeycomb-shaped lattice (44), the outline shape of one honeycomb being a predetermined stretched hexagon (70), which is stretched into the direction of the viewing screen height. 5

28. Procedure for producing a viewing screen according to one of the preceding claims, comprising the following production steps: a) laying an elastic metallically reflecting foil (43) onto a lattice (44), which forms the front side of a gasproof frame construction (42) and is connected . with it, and fixing the foil to the circumference of this frame construction in a gasproof manner, 19 b) generating an underpressure (45) inside the gasproof frame construction in such a way that the foil (43) obtains a predetermined curvature in the individual openings of the lattice (44), which forms the front side of the frame construction, 5 c) fixing of the foil (43), with the curvatures shaped in the individual lattice openings.

29. Procedure for producing a viewing screen according to claim 28, wherein the fixing of the foil, in production step c) is carried out in such a way that a material 10 that can harden is applied to the outside of the structured foil which is exposed to the ambient pressure, while maintaining the underpressure (45) inside the gasproof frame construction (42).

30. Procedure for producing a viewing screen according to claim 29, wherein for 15 fixing the foil a fast hardening resin (49) is applied to the outside of the foil (43) as the material that can harden.

31. Procedure for producing a viewing screen according to one of the claims 28, 29 or 30, wherein a further procedural step is added: 20 - joining of the foil having the fixed surface structure (50) with a support plate (55) by using a form press tool having plane or curved press areas (57), the form press tool consisting of a form press tool top (52) and a form press tool base (53), whereby the support plate with the side not equipped 25 with an adhesive substance (54) is put on to the press area of the form press tool base and the foil with the fixed surface structure (50) is put on the press area of the form press top and wherein, when closing the form press tool, the foil is joined to the support plate. 3o

32. Procedure for producing a viewing screen according to one of the claims 1 to 27, further comprising these steps: a) production of a prototype-viewing screen based on one of the procedures according to one of the claims 28 to 31, b) moulding of embossing plates (58) by means of the prototype screen, c) production of a viewing screen by means of the embossing plates (58). 0

33. Procedure for producing a viewing screen according to claim 32 wherein in production step c) embossing rollers (59) are used.

34. Use of a viewing screen according to one of the claims 1 to 27 for deflecting light beams, especially for illumination tasks, wherein the viewing 5 screen may be illuminated with a source of light, and wherein the screen may additionally be equipped with swivel drives.

35. Use of a viewing screen according to one of the claims 1 to 27 as an advertising board or as an information board, wherein a unicoloured or a _ multi-coloured metallically reflecting image or text, as a thin layer, is further applied to the surface structure of the viewing screen, and wherein the viewing screen is illuminated by a light source. 20 Designations reference list: 1 viewing screen 2 micro-mirror surface structure 3 pattern with a honey-comb-lattice-like structure 4 micro mirrors with a defined elliptical outline shape 5 micro mirrors with a defined stretched hexagonal outline shape 6 projector light 7 elliptical or oval light cone 8 approximately elliptical or approximately oval light cone 9 long half-axis of micro mirror 10 short half-axes of micro mirror 11 ( slight ) vertical curvature 12 ( strong ) horizontal curvature 13 vertical reflection angle of micro mirror ( ay) 14 horizontal reflection angle of micro mirror ( ax) 15 horizontal reflection angle of the viewing screen 16 vertical reflection angle of the viewing screen 17 projection zone ( spatial overlaying zone of all reflected light cones emanating from the micro mirrors) 18 point of intersection of the optical axes of the micro mirrors 19 loss-space ( non-usable part of the reflected light) 20 most optimal area of the projection zone 21 curved viewing screen 22 sphere centre point of the spherical curved viewing screen 23 plane viewing screen 24 sectors 25 different spatial orientation of the micro mirrors 26 centre normal of the viewing screen (surface normal of the viewing screen centre) 27 uniform spatial orientation of the micro mirrors 28 corner sectors of the viewing screen 29 sector in the viewing screen centre 30 square or rectangular sectors 31 sectors with a circular-shaped, ellipse-shaped or oval-shaped ring-segment shape 32 sectors with a polygon-shaped ring-segment shape 33 stair-like displacement of the micro mirrors 34 interference light source 21 35 micro mirror on the upper edge of the viewing screen 36 micro mirror on the lower edge of the viewing screen 37 interference light cone caused by the micro mirror on the upper edge of the viewing screen 38 interference light cone caused by the micro mirror on the lower edge of the viewing screen 39 uncritical angle area 40 critical angle area 41 orientation angle of the optical axis of the micro mirror, dependent on the position of the micro mirror on the viewing screen 42 gasproof frame construction 43 elastic metallic reflecting ( metal-coated ) foil 44 ( honeycomb-shaped ) lattice 45 underpressure + fluid ( e.g. air) 46 device for the generation of a predetermined pressure 47 sealant glue 48 foil which is structured through the underpressure 49 fast-hardening resin 50 structured foil with fixed micro mirror surface structure 51 automatic spray equipment 52 form press tool top 53 form press tool base 54 adhesive substance ( adhesive layer) 55 support plate 56 finished viewing screen 57 form press tool ( closed) 58 embossing plates ( prress tool with embossing plates) 59 embossing rollers ( press tool with embossing rollers) 60 micro mirror surface structure of the embossing plates or embossing rollers 61 vacuum-metallisation process 62 metallic reflecting surface 63 metal-coated viewing screen plates or viewing screen foils 64 additional coatings ( e.g. protective coatings or coatings with optical properties) 65 micro mirrors with a defined oval outline shape 66 micro mirrors with an outline shape which corresponds with a defined polygon (line) which approximates to an ellipse or an oval 67 device for the generation of an electrostatic or electromagnetic field 68 device for the generation of a predetermined pressure 69 substructure 22 70 hexagon which is stretched in the direction of the viewing screen height 71 the inner or outer surface (depending on the use of concave or convex mirrors) of a cap-like part, cut out of a defined hollow (or thin-walled) ellipsoid, ovaloid, rotation ellipsoid or rotation ovaloid 72 concave curvature ( concave mirror) 73 convex curvature ( convex mirror) 74 projector 75 micro mirrors with a circular outline shape (for comparison !) 76 circular light cone 77 optical axes of micro mirrors 78 coarse division into sectors 79 fine division into sectors 80 enlargement of the details in the section-views ( small circles in the section-views) 81 distance to the projector 23 Summary: Viewing screen to achieve a spatially exactly defined image projection of high light intensity with a big horizontal reflection angle but a small vertical reflection angle. The viewing screen 1 consists of a plate-like or a foil-like basic material whose surface comprises concave or convex mirrors of the same size and with the same mirror curvatures lying side by side. The micro mirrors of the micro mirror surface structure 2 created in this way preferably have an elliptical outline shape 4 or a stretched hexagonal outline shape 5. The micro mirrors are arranged on the screen surface in a predetermined pattern 3 with a honeycomb-lattice-like structure in such a way that their long mirror half-axis is orientated in the vertical direction. Because the micro mirrors have different curvatures in the horizontal and vertical direction, the projected light 6 is reflected in the form of an elliptical light cone 7 or in the form of an approximately elliptical light cone 8. The micro mirrors are orientated spatially in such a way that their optical axes intersect at a defined point of intersection 18 on the centre-normal of the viewing screen 26. In this way a spatial overlaying zone 17 of all light cones reflected by the micro mirrors is created, in which the reflected image can be seen. In loss areas 19 outside this overlaying zone 17, only very small amounts of light or no light is reflected. In this way, a viewing screen of high light intensity with very good contrast is created, as the viewing screen is relatively insensitive to interference light sources (e.g. ceiling light) because of the small vertical reflection angle.