MX2010012257A - Projection screen and method of construction. - Google Patents

Abstract

A projection screen (2) having a retention member (3, 4) configured, in use, to be in contrast with at least one surface of the screen (2) along at least a portion of at least one edge of the screen. The projection screen (2) may comprise polymeric material, such as a biaxially oriented foil, and the retention member (3, 4) is bonded to the screen. The retention member (3, 4) may comprise a plurality of apertures (8) and a plurality of tensioning members (6) extending through the apertures (8) to apply tension to the screen (2). A portion of each tensioning member (6) that extends through one of the apertures (8) to contact the retention member (3, 4) may be flexible and non-resilient. The retention member (3, 4) may be configured to allow slidable engagement with the plurality of tensioning members (6). Each retention member (3, 4) may additionally comprise biasing means (54) configured to bias each retention member (3, 4) away from a neighbouring retention member, the biasing means (54) adjustable to vary the bias applied to the retention member (3, 4) when the screen (2) is in situ.

Description

PROJECTION SCREEN AND CONSTRUCTION METHOD DESCRIPTIVE MEMORY The invention relates to a projection screen and its method. More particularly, but not exclusively, it refers to a projection screen attached to a retention member and to a method for constructing said screen.; The projection of an image on a partially reflecting and transparent screen in such a way that it can be seen by an observer in front of the screen is known as the "Pepper Ghost" arrangement at fairs.

Pepper's Ghost projections have been used in advertising and in promotional displays, where a presenter is behind a partially reflective and transparent slanted screen, usually a stretched film, on which an image of, for example, is projected. example, a motorized vehicle, by means of at least one reflective surface, see for example EP 0799436. The location of the presenter behind the projected image has a series of inherent advantages over those systems where the presenter becomes delarité of a screen, not forgetting that the presenter must not obscure the projected image while walking through the projected image. In addition, the use of a tilted screen makes the viewer perceive the image perceived in the background instead of capturing it as a two-dimensional image, for example when a motor vehicle is seen turning on a platform rotating However, current imaging devices have a series of problems associated with them, for example, the assembly of the blade sheet can be difficult, which in turn leads to uneven tension of the sheet and wrinkles in the sheet, which deteriorate the quality of the image seen . It is well known in the art that wrinkles are formed and inevitably on a screen over time with a distortion I resulting from the projected image. In fact, a wrinkle-free screen can be mounted at night and, for the next morning, wrinkles will have appeared as a result of loosening of the screen. In addition * a change in conditions, such as humidity or temperature, can cause wrinkling in minutes. In practice, it has been found that due to the thickness of large sheets (for example, the sheets of 4 meters long are 88-110 microns thick and the sheets of 5.5 meters long are approximately 50 microns thick). Loosening, the screen often only occurs after approximately 48 hours. When wrinkles appear, it is necessary to retighten the screen and, in particular, the required voltage levels exceed those that are obtained only with the strength of the user. | WO 2005/096095 (Musion Systems Limited) provides an apparatus capable of providing a uniform tension of the sheet by applying pressure in a plurality of positions along the length of minus one edge of the screen. This device requires placing an edge of the screen between jaws and pass a bolt through the screen. A nut it is then screwed onto the bolt and tightened to keep the screen jentre the jaws. The tensioning is provided by means of straps that are attached to the jaws. Each of the tension belts can be individually tightened or clamped to allow the application of uniform tension over the entire screen.

It is becoming a growing need [the projections of Pepper's ghost in more unusual places and the same I! mode a great need for projection images that require sizes larger screen sizes (such as those greater than 5 meters length). This imposes an increasing burden on the complexity of construction of a projection apparatus capable of projecting an image of high quality. 1 Thus, according to a first aspect of the invention, provides a polymeric projection screen having a retention member configured, during use, to be in contact with at least a surface of the screen along at least a portion of the minus one edge of said screen, wherein the retention member: is glued to the screen.

The invention therefore provides a simplified arrangement with respect to that described in WO 2005/096095 and in other projection screens. For example, a screen width of 12 meters would require I approximately 44 holes in the screen. This not only consumes a lot of time but there is a high probability that the screen will tear, damage or weaken the overall resistance of the screen. In contrast, the present invention provides a simplified arrangement wherein the retention members can simply stick to the screen at any point without the need to create holes in the screen and to weaken the screen. The screen lamina - thus, a m an m m m m requires ograms and deformation to the break to be applied) required to completely eliminate the wrinkles without suffering damages. j It will be appreciated that the retention member may comprise two separate retention members placed on either side of the retention member. the screen in such a way that contact is achieved with both surfaces of the screen. However, in an alternative embodiment, the retention member comprises a single extruded retention member as a substantially U-shaped member such that contact is achieved on both surfaces of the screen. For example, the retention member comprises a I channel through which the screen can pass before sticking to it. In a further alternative embodiment, the retention member comprises a single retention member such that contact is achieved on a single surface of the screen.

It will be appreciated that the retention member can be constructed of a variety of desirable materials capable of withstanding the high pressures that will be exerted on the screen during the tensioning process. In one embodiment, the retaining member is constructed of a lightweight metal (aluminum, for example) or a plastic material. The retaining member can be made of a flexible material, so that the retaining member fixed to the screen can be wound around a cylinder, for example, a cylinder having at least a diameter of 50 cm and j. preference with a diameter between 80 to 100 cm. This is advantageous, since the retention member can be connected to the screen at one location and compacted to be delivered at another location by winding the screen and the attached retention members around a cylinder. At the delivery site the screen and the retention member can simply be unrolled and raised without the need to connect the members of I retain and have the necessary tools to fix the retention members at the place of delivery. The retention members can be left with a plastic material that can be extruded. Extrude retention members! it is convenient since very long retention members can be formed, for example 100 m long, so that there is no need to join separate retention members to form a screen. Joining separate retention members, such as steel retention members, can produce undesirable wrinkles on the screen. In another modality, the member 'of Retention is constructed from a plastic material, such as a plastic material (e.g., polyethylene terephthalate, PET).

The polymeric projection screen can be constructed of a light weight material, such as polyester. The use of light weight material is uni tain because it allows easy manipulation and mounting of the screen on a stage.

It will be appreciated that the joining process will usually comprise any means for sticking the retention member to the screen without the need to make holes in the screen. In one modality, the bonding will be irreversible. I In a modality the bonding comprises a sticking what! It is suitable for use with polymeric materials, for example, the use of solder as ultrasonic welding.

In one embodiment, gluing can be achieved by a single, continuous welding or a series of welds in a plurality of positions. The application of a continuous weld requires the screen to extend over a flat surface, which is not always possible or convenient for large screens in places with limited space. Thus, in a preferred embodiment, the gluing is provided by a series of welds (eg, spot welding) in a plurality | of positions. Spot welding (for example, varying in size from about 2 to 3 mm in diameter or greater, such as approximately 10 x 15 mm) can be applied by portable welding equipment (for example example, ultrasonic welding equipment). Said equipment is easily available and will usually provide ultrasonic energy at a resonance frequency i between 20 and 40 kHz. This allows a simple attachment of a retention member to an edge of the screen.

In an alternative embodiment the gluing comprises the use of a chemical agent (eg, an adhesive). It will be appreciated that the chemical agent can be applied in a manner analogous to that of the ultrasonic welding described above (i.e., either in a single application, continuous or a series of applications in a plurality of positions).

In an alternative mode, even additional, the gluing I It includes the use of vacuum bonding. Said modality will be based on the use of a material that when applying pressure to the screen and to the retention member cricket. It will be appreciated that vacuum bonding can be provided by directly attaching the retention member to the screen or can be provided by indirectly attaching the retention member to the screen i? by the presence of an additional rubber substrate between the retaining member and the screen. This modality offers significant advantages over! the other forms of bonding mentioned above in which the bonding is reversible and it can be used again Positioning retention members along an edge of the screen evenly can be a difficult task and vacuum bonding will allow rearrangement to ensure that; the retention members are placed in the optimal position. Furthermore, the bonding properties will be maintained even when subjected to the influences of heat and humidity. In addition, the pressure necessary to form the vacuum bonding is very low, so that the screen is subjected to a lower pressure to the traction and is less likely to suffer damage during the bonding process. Although constructed in a totally different manner to the screen apparatus described in WO 2005/096095, this document describes the presence of an abrasive coating (such as sandpaper) between the screen and the retaining member to improve the grip on the screen. This abrasive coating causes significant scratching on the screen and in view of the thinness of the screen is very likely to damage the screen and weaken the overall strength of the material. On the other hand, if insufficient force is applied between the retention member and the screen, then the screen will slide and cause undesirable wrinkles on the screen. Therefore, the abrasive coating provides a series of disadvantages, each of which is solved by the gluing arrangement of the invention (in particular, the vacuum gluing mode).

In an alternative embodiment, gluing comprises a first retention member composed of a magnetic material in collaboration with. a second retention member composed of a material either metallic or magnetic. This modality of magnetic union offers the significant advantage of guaranteeing a strong union when inserting the screen between two i retention members, in addition to providing a reversible union process. It will be appreciated that the magnetic material will be any suitable magnet capable of strong fixation with a corresponding metallic or magnetic material. Examples of magnetic materials are iron ore (magnetite or magnet stone), cobalt, nickel, gadolinium, dysprosium and rare earth magnets, such as samarium (for example, samarium and cobalt) and neodymium (for example, neodymium magnets). iron-boron (NIB)). In one embodiment, the magnetic material is neodymium (for example, neodymium-iron-boron man (NIB)). In addition to the embodiment of the magnetic retention member, it is also envisaged that pre-existing metal retention members can be secured to a screen using magnetic pins made of a magnetic material as described above for the magnetic joining mode. For example, the nut and bolt arrangement could be replaced with a single magnetic bolt that holds the screen firmly in place without the need to tighten a bolt nut.

In one embodiment, the retention member is located along two opposite sides of the screen. However, it will be appreciated that the retention member does not have to run all along the edge of the screen. For example, in one embodiment, the length of the retention member may correspond to the length of the screen. In an alternative embodiment, the retention member may comprise a further series of lengths cuts along the entire length of the screen. These modalities would find application in a wide range of different sizes and screen shapes, in particular, unconventional shapes such as triangular, pentagonal, hexagonal or octagonal.

Once the retention member has been attached to the screen as defined, the screen is then tensioned to eliminate all wrinkles. The tensioning process typically encompasses the attachment of a plurality of tensioning members to the screen at one end of the tension member, with the other end of the tensioning member being attached to a frame or tie member. Tension members usually include a strap or cable that has a ratchet or friction locking buckle. The tensioning members will then be tightened or loosen to result in a wrinkle free screen.

The great advantage of the joining mode of the invention is provided when the screen is tensioned on two opposite sides. If a wrinkle appears later, then the attached retention member described herein can be adapted to the screen on any of the remaining sides of the screen in order to eliminate the wrinkle simply and efficiently. For example, the pressure could be applied in a different direction to the one applied previously, which is more likely to eliminate wrinkles than the simple application of increased pressure in the current direction. This provision of on-site addition of additional retention members and I Tensioning members would not have been possible with the provisions without completely dismantling the apparatus. The invention therefore represents a significant advance in terms of current projection arrangements.

In one embodiment, the screen has one or more portions of I cutout or openings. These portions will be non-reflective and normally ; i will allow to position a projector so that the image can be . i. directed through the clipping portion (or window). This arrangement has the important advantage that the "cornerstone effect" (the creation of elongated or distorted images that occur due to the projection angle) is reduced. Clipping portions can also allow you to place various struts in a live setting that can protrude through the pantyhose and create a more realistic three-dimensional environment. Prior to the invention, these cutting portions would not have been possible due to the restricted tensioning measures. The provision of the addition on the members' site; Individual retention in any position around the screen provides an effective way of tensioning a screen to be wrinkle free, even when trimming portions are present.

In one embodiment, the retention members comprise means for securing a plurality of tensioning members. In one embodiment, the fixing means comprise a plurality of apertures Therefore, according to a second aspect of the invention, a projection screen having a member is provided. retaining j configured, in use, to be in contact with at least one screen surface along at least a portion of at least one edge of said screen, the retaining member comprises a plurality of openings, and a plurality of tensioning members that extend through the openings to apply tension to the screen, where (a I portion of each tensioning member that extends through one of the openings to be in contact with the retaining member is flexible non-elastic. In this way, the forces applied by the tensioning members are substantially in a plane of the screen. In particular, any deviation of the tensioning members between a fixing point and the plane of the screen causing a rotation of the tensioning member does not result in excessive torsional forces applied to the screen. For example, if the tensioning member composed of a rigid portion passing through the opening to contact the retaining member, the twisting of the tensioning member due to the deflection could result in the rigid portion being jammed. through the opening, resulting in the transmission of torsional forces to the screen. Such torsional forces could create imperfections, such as wrinkles, on the screen.

In this embodiment, a tensioning member can be threaded through the opening and pressure can be applied to both ends of the tensioning member in the same direction. This provision establishes! a simplified fixing mechanism that also has the advantage of being lightweight . i due to the presence of the openings. In one embodiment, the openings are circular, oval or elongated slots. In a preferred embodiment, the openings are elongated slots.

Each tensioning member may encompass a more flexible and non-elastic portion away from a point of contact with the retaining member. In this way, the tensioning member can rotate between the attachment point and the retaining member to compensate for any deviation.

The tensing members can be belts, such as canvas belts, rope or the like. In an alternative embodiment, the retention members are configured to allow sliding engagement with the tensioning members.

Therefore, according to a third aspect of the invention, there is provided a projection screen having a retaining member configured, in use, to be in contact with at least one surface of the screen along with less a portion of at least one edge of said screen, wherein the retaining member is configured to allow a slidable coupling with a plurality of tensioning members configured to apply tension to the screen.

Such an arrangement offers the advantage that the tensioning members can be moved to any position. This system solves the problem of eliminating a wrinkle that appears between the positions of two fixed tensioning members. In this embodiment of the invention, a sliding tension member can be loosened, slid in the wrinkle position and immediately tensioned to eliminate wrinkling.

According to a further aspect of the invention, there is provided a projection screen having a plurality of retention members configured, in use, to be in contact with at least one surface of the screen substantially around the periphery of said screen, wherein each retention member further comprises diverting means configured to deflect each retention member away from a neighboring retention member, the deflection means are adjustable to vary the deflection thereof.

Retention member will result in a wrinkle free screen. The detour can be adjusted to eliminate / prevent the appearance of wrinkles. For example, wrinkles can be produced by changes in conditions, such as changes in humidity or temperature and / or due to the relaxation of screen tension over time. On the other hand, this aspect of the invention does not require a separate frame. The retention members around the periphery of the screen allow a self-supporting screen that does not require mounting to a frame or the addition of independent tensioning devices with respect to conventional projection devices and they have been achieved optimal results with this aspect of the invention when the screen is circular.

In one embodiment, the diverting means will comprise a spring or other resilient member. In an alternative embodiment, the bypass means will comprise mechanical means for manually increasing the bypass force exerted between each retention member. Such mechanical means may comprise a threaded nut that is capable of extending or retracting the distance between each retaining member in order to adjust the desired amount of diverting force applied between each retaining member.

It will be appreciated that the retaining member of the self-tensioning aspect of the invention may comprise any suitable retention member (either described above or conventionally available). In one embodiment, the retaining member comprises two components that hold the screen in place by a jaw action. ! It will be appreciated that the retaining members described herein constitute separate items of trade of the screen itself and therefore represent additional embodiments of the invention. In particular! the retaining member described for the self-tensioning aspect of the invention comprising the diverting means also represents a separate aspect of the invention.

In one embodiment, the screen is a sheet. In another embodiment, the screen comprises a partially reflecting layer at least on surface. In one modality, the panther is constructed with the same matejrial as the retention member. In an additional embodiment, the screen is constructed from a plastic material (for example, polyethylene terephthalate, PET). In a further embodiment, the screen is constructed from a biaxially oriented plastic sheet.

According to a further aspect of the invention, a projection screen comprising a biaxially oriented polymer sheet is provided. j The biaxial stretching that occurs in polymer extrusion and polyester during manufacturing improves the mechanical properties of stiffness and resistance by orienting the molecules in the sheet. Of importance is the fact that this stretching process ensures that the mechanical properties are similar in the longitudinal direction (along the length of the screen roll) and in the direction transverse to the width of the sheet. It is this property of the screen that allows the mounting of the screens when a general tension is applied in one direction only, for example from the background : 1 to the top or from side to side. Since the sheet has similar properties in both directions, wrinkles are removed with some ease as long as the sheet remains stable in orientation from top to bottom. lower as tension is applied.

If the sheet is not biaxially oriented the wrinkles would be more difficult to remove when the tension is applied only in one direction, since the sheet would tend to narrow across its width. East Narrowing across its width (or length if the tension is applied only from side to side) can be greatly stabilized by the use of retaining members applied to intercalate the edge region of a sheet. The retaining members may have bolts that pass through the sheet or have abrasive or bonding materials applied to their inner faces which, once the retaining member is applied, prevent slippage (or contraction) of the sheet, preferably not only in the sense in which the tension is applied, but in all directions. In addition, the control; Sliding can be extended to the corners removed from the sheet.

An additional aspect to the elimination of wrinkles on the screens is the need for high voltage loads. The screens therefore need to have sufficient mechanical properties to withstand these loads otherwise the screens will stretch and tear. The molecular stretching process in the manufacture of biaxially oriented polymer sheets results in better mechanical properties that are able to withstand the higher mounting loads. Screens made of biaxially oriented plastics are also superior to those made of blown or cast film due to these better mechanical properties.

The biaxial sheet may comprise a silver coating. The biaxial sheet may be a contrasté sheet (a sheet sheet having a gray or black dye).

According to a further aspect of the invention, it is provided; an image projection apparatus comprising a light emitting device, a frame, and at least one partially transparent screen as defined, the frame being arranged to maintain the screen under tension, such that the screen is inclined at an angle to the A plane of light emission of the light emitting device, the screen has a front surface arranged in such a way that the light emitted from the device of deployment is reflected from there, and the light-emitting device is arranged It will be appreciated that the light emitting device is any light source that is capable of being reflected from a screen at least partially transparent. Examples of light-emitting devices include a projector, a liquid crystal display (LCD), a thin-film transistor (TFT) screen, a plasma screen or a light-emitting diode wall (LED) (for example, a high-gloss LED wall with variable dot density between 2-30mm between each LED).

The light-emitting device can also include design objects from the set and stage illuminated by a light that does not have to I , I show image processing capabilities.; | According to a further aspect of the invention | A method for constructing a projection screen comprising the steps of: (A) bringing a retention member into contact with at least one surface of the screen along at least a portion of at least one edge of said screen; Y (B) joining the retention member to the screen.

In another embodiment, the method further comprises the steps of: (c) fixing the at least one portion of at least one edge of said screen to a frame or stringer member by one or more members of i tensed; Y (d) applying tensile force to one or more tensioning members.

The retention member can be made of a material In addition, the method can also comprise winding the projection screen around a cylinder. In this way, the projection screen! It can be delivered at a desired location.

According to a further aspect of the invention, method of constructing a projection screen comprising a) extruding polymeric retention members configured, for use, to be in contact with at least one surface of a screen and b) attaching the retention members to the screen.

The method may comprise cutting the extruded retention members to an appropriate length for the screen before gluing the retention members to the screen. . i It will be appreciated that the features and elements of the invention described above for the screen are also applicable to the method described above.

For example, it will be appreciated that the method of the invention not only finds application in the initial construction of the screen, but also in the in situ tensioning of the screen after its construction with the firl of I Remove wrinkles during the loosening process.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a front and side view of the ultrasonic gluing mode of the invention; i Figure 2 shows a front and side view of the ultrasonic gluing mode of the invention with the addition of a retention member in situ; Figures 3 and 4 show a front and side view of the . i method of vacuum bonding of the invention; Y Figures 5 to 7 show different views of the embodiment of the retention member with self-tensioning of the invention.

Referring first to Figure 1, a projection apparatus that is generally shown as 100, consists of a polymeric projection screen 2, retention members 3, 4, tensioning brackets 5, tensioning belts 6 and a series of welds per ultrasonic point 7. The screen 2 is shown as a sheet and the retention members 3 are shown. show each one as an extruded plastic clamping bar or molded (eg PET), although it will be appreciated that they could contemplate other means of construction.

During use, the screen 2 is inserted into the extruded channel 30, 40 of each of the retention members 3, 4 and then stick by 1 ultrasound to create the spot of welds by points 7. The peg 1ado Ultrasonic will be created using a portable ultrasonic welding device comprising an ultrasonic horn backed by a small anvil of hand. The horn is connected by a cable to a generator high frequency ultrasonic capable of generating ultrasonic energy in the scale from 20 to 40 kHz. Each spot welding can usually vary approximately 2 to 3 mm in diameter or greater and takes 1 to 2 seconds to be created. Tensioning brackets 5 are configured to fasten to the profiled cross-section of the retaining members 3, 4 and then tensile force can be applied to the screen by Tensioning straps 6. Tensioning mode shown in Figure 1 It comprises the sliding coupling mode. For example, yes wrinkles appear after loosening of the screen, a strap) tensioned can be released, slide to a suitable position and then turn to tense to eliminate the wrinkle. It will be appreciated that the arrangement slides ^ of the corbels which finds applicability in other ways of fixing the screen and the retention member. | Figure 2 shows a projection apparatus generally shown as 200, comprising a polymeric projection screen 2, retaining members 3, 4, tensioning belts 6, a series of ultrasonic spot welds 7 and a series of elongated grooves 8 in each row of the retention members 3, 4. Screen 2 is shown as a sheet and 7. In particular, according to a portion of the belt 6 extending through the openings 8 is flexible and elastic the belts do not apply significant lateral forces to the retaining member in the event that a torsion of the belt 6 occurs. The forces applied by the tensioning straps 6 to the screen 2 are substantially in the plane of the screen 2.

In use, the screen is glued to retention members 3, 4 of I identical to that described for the embodiment of Figure 1. The tensioning arrangement in Figure 2 differs from Figure 1 in that a tension bracket 1 i separated is not necessary. Each tensioning strap 6 passes directly through the opening 8 present in the retaining members 3, 4. Another difference between figures 1 and 2 is the presence of a separate retaining member which can be glued after the initial construction of the apparatus i 2. 3 of projection. In the event that a wrinkle appears after loosening of the screen, an additional retaining member 22 can be ultrasonically bonded to the screen 2 with spot welds 21 in the exact position of the screen 2, which could facilitate eliminating the wrinkle. The The screen can be tensioned by passing a tensioning strap 24 through an opening 23 present in the retaining member 22 and by applying a pulling force to the screen 2 to remove the wrinkle. It will be appreciated that the tensioning arrangement comprising openings constitutes an inventive feature It is additional and finds applicability in other ways of fixing the screen and the retention member.

Figure 3 shows a projection apparatus shown! in general with the 300, which comprises a projection screen 2, retaining members 3a, 3b, 4a and 4b, tension brackets 5, tensioning belts 6 and rubber vacuum forming strips 10, 11, 12 and 13. screen 2 is shown as a sheet and retaining members 3a, 3b 4a and 4b are each shown as extruded aluminum fastener bars, although it will be appreciated that other means of construction could be contemplated.

In use, a rubber vacuum forming strip 10 is placed against the retaining member 3a and an additional rubber vacuum forming strip 11 is placed against the retaining member 3b. An edge of the screen 2 is then placed between the retaining members 3a and 3b (such that the rubber vacuum forming strips 11 and 12 are sandwiched between the retaining members and one surface of the screen). Pressure is then applied to the edge of the screen in order to stick the screen of 2 to the retaining members 3a and 3b through a vacuum bonding process from the vacuum forming strips in rubber 10 and 11. the same process is repeated for an opposite edge of the screen 2 using rubber vacuum forming strips 12 and 13 and the retaining members 4a and 4b.

The tensioning mode shown in Figure 3 comprises the sliding coupling mode exactly as described in Figure 1.

Figure 4 shows a projection apparatus generally shown with the 400, comprising a projection screen 2, retention members 3a, 3b, 4a and 4b, tensioning straps 6, a series of elongated slots 8 within each of the retaining members 3a, 3b, 4a and 4b and rubber vacuum forming strips 10, 11, 12 and 13. The screen 2i is shown as a sheet and the retaining members 3a, 3b 4a and 4b are each shown as extruded aluminum fastening bars, although it will be appreciated that other means of construction could be contemplated. The bonding process can be carried out exactly as described in Figure 3 and the tensioning process can be carried out exactly as described in Figure 2.

; I In an alternative mode, the vacuum forming strips,! in The rubber 10, 11, 12 and 13 can be inserted between retention members in conventional projection apparatuses (for example, in one which uses the drawback holes with bolts). In this mode, the rubber strips will simply replace the abrasive coating used previously to solve the aforementioned problems. It will be appreciated that in the case that the fixing bolts and holes are present, in particularly with the sliding tensioning arrangement, that the heads of the bolts will be embedded within the retaining member to allow the sliding of the tensioning bracket.

Figure 5 shows the self-tensioning aspect of the invention.

The retaining member 50 comprises two components 51, 52 which are configured to intersperse the screen with a jaw action exerted by the screw 53. The C-couplers 61 join the members 51 and 52. The diverting means 54 are shown in greater detail in Figure 6, where ! It can be seen that they comprise two fixing means 55, 56 for fixing the diverting means 54 to two neighboring retention members 50. The means of deflection 54 also comprise a spring 59, which is held against a threaded nut 60. The diverting means 54 also comprise orifices of 58 for receiving a pin 57 for biasing the fastening means 55 in a fixed position, if desired.

Figure 7 shows the self-tensioning mode fixed to a Wrinkles are produced on the screen or a higher level of tension than that exerted naturally by the spring 59 is required, then manual adjustment can be made by tightening or loosening the threaded nut 60.

It will be understood that the self-tensioning aspect of the invention is not limited to circular screens, but can be applied to other screen shapes.

In one embodiment, the projection screen is a biaxially oriented polyester film.

Claims (23)

NOVELTY OF THE INVENTION CLAIMS

1 .- A polymeric projection screen that has a member of retention configured, during its use, to be in contact with the meoos I a surface of the screen along at least a portion of the : i minus one edge of said screen, where the retention member! this stuck to the screen. '

2. - The screen according to claim 1, characterized further because the retention member is a member substantially U-shaped

3. - The screen according to claim 1 or claim 2, further characterized in that the retaining member is weld to the screen.

4. - The screen according to claim 3, characterized in that said welding comprises a series of welds in a plurality of positions. i I

5. - The screen according to claim; 1 o claim 2, further characterized in that the retention member is stuck to the vacuum to the screen.

6. - The screen in accordance with the claim and claim 2, further characterized in that said gluing comprises a first retention member composed of a magnetic material in collaboration with a second retention member composed of a material either metallic or magnetic.

7. - The screen in accordance with any of the ; i above claims, further characterized in that it comprises one or more trimming portions or openings.

8. - The screen in accordance with any claim I above, further characterized in that the retaining members comprise means for securing a plurality of tensioning members.

9. - The screen according to claim 8, further characterized in that the fixing means comprise a plurality of openings.

10. - A projection screen having a retention member configured, in use, to be in contact with at least one surface of the screen along at least a portion of at least one edge of said screen, the retention member comprises a plurality of openings, and a plurality of tensioning members extending through the openings to apply tension to the screen, wherein a portion of each tensioning member extending through one of the openings to be in contact with the retention member is flexible non-elastic.

11. - The screen according to claim 10, further characterized in that the tensioning members comprise belts, cables or the like.

12. - A projection screen that has a member | retainer configured, in use, to be in contact with at least one surface of the screen along at least a portion of at least one edge of said screen, the retaining member is configured to allow a slidable engagement with a plurality of tensioning members configured to apply tension to the screen. :

13. - A projection screen having a plurality of retention members configured, in use, to be in contact with at least one surface of the screen substantially around the periphery of said screen, each retention member further comprising ; diversion means configured to deflect each retention member; away from a neighboring retention member, the deflection means are adjustable to vary the deflection applied to the retention member when the screen is in place.

14. - The screen according to claim 13, further characterized in that the bypass members comprise a spring or other elastic member.

15. - The screen according to claim 13 : | further characterized in that the diverting means comprise means 30 mechanics to manually increase the deflection force exerted between each retention member.

16. - A projection screen comprising a biaxially oriented polymeric sheet.

17. - A retention member as defined in any of claims 6 or 13 to 15.

18. - The screen according to any of the preceding claims, further characterized in that it is a sheet.

19. - The screen according to any of claims 1 to 16, further characterized in that it additionally comprises a partially reflective layer on at least surface.

20. - An image projection apparatus comprising a light-emitting device, a frame, and at least a partially transparent screen according to any of claims 1 to 1; 16 and, 18 to 19, the frame being arranged to maintain the screen under tension, such that the screen is inclined at an angle to a plane of emitting light from the light emitting device, the screen has a front surface arranged in such a way that the light emitted from the light-emitting device is reflected from there, and the light-emitting device is arranged to project :, t an image so that the light from the light emitting device impinges on the screen so that a virtual image is created from the light reflected from the screen, the virtual image appearing as located behind the screen.

21. - A method for constructing a projection screen comprising the steps of: (a) bringing a retention member into contact with at least one surface of the screen along at least a portion of at least one edge of said screen; and i (b) attaching the retention member to the screen.

22. - The method according to claim 21, further characterized in that it additionally comprises the steps of: (c) fixing the at least one portion of the at least one edge of said screen to a frame or strut member by one or more tensioning members; Y! (d) applying tensile force to one or more tensioning members.

23. - The method according to claim 21, further characterized in that it also comprises winding the projection screen with retaining members glued thereto around a cylinder.