Speckle mitigation for projection screens

Abstract

Methods and apparatus for mitigating speckle on an image projection screen are disclosed. A shaking or vibrating of the projection screen may be achieved using actuators mounted directly to a semi-flexible lacing bar or pressing on the screen near an outer frame member. The outer frame member or lacing bar may be rigidly mounted to structural members at mounting points, and the actuators may be mounted to the outer frame member or lacing bar at positions between those mounting points. A controller may generate and transmit signals toward the actuators, the signals configured to cause movements of the actuators that cause the screen to shake at one or more prescribed frequencies. Such motion may at least partly mitigate a visual perceptibility of the speckle.

Description

SPECKLE MITIGATION FOR PROJECTION SCREENSBACKGROUND1. Related Applications

[0001] This application claims the benefit of priority from US Provisional Patent Application No. 63 / 678,991, filed August 2, 2024 and US Provisional Patent Application No. 63 / 723,550, filed 21 November 2024, and EP application No. 25154433.4 filed January 28, 2025, each of which is incorporated by reference herein in its entirety.2. Background

[0002] The present disclosure relates generally to the field of image projection, and more specifically to enhancing displayed images on a laser projection screen, wherein techniques disclosed herein are directed to mitigation of speckle artifacts on the projection screen.3. Description of Related Art

[0003] Speckle refers to a visual artifact that can be perceived by a viewer as a granular interference pattern. Speckle may occur when a rough surface (e.g., a projection screen) is illuminated by a coherent light (e.g. a laser beam). A speckle pattern observable by the viewer in the image plane of the surface is known as a “subjective speckle pattern.” Subjective speckle is an artifact that appears as a static strong noise pattern. It does not necessarily occur on the projection screen itself, but between the screen and the eyes of the observer. Each observer may see a different subjective speckle pattern, although the overall characteristic might be similar. Subjective speckle patterns can and do change and depend on the viewing conditions, such as movement of the observer, size of lens aperture, or position of the imaging system.

[0004] While objective speckle that falls on a surface can often be addressed with fixed changes to the optical design, subjective speckle occurs due to interference between the screen surface features and the human eye. As such, changes to the projector optical system are often ineffective, particularly on large screen applications. Subjective speckle is highly objectionable for observers because the pattern creates visual noise and may cause uneven reflectivity across the screen. Subjective speckle thus plagues purveyors of projection and other display systems that utilize laser illumination, due to the coherence of laser light.SUMMARY

[0005] In one example, a system for screen shaking is provided. The system includes a projection screen having a viewing surface, a lacing bar, and first and second attachment structures rigidly connecting the lacing bar to external structural members. The first and second attachment structures are connected to the lacing bar at first and second points along a first edge of the projection screen. The system includes an actuator configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar at a position that is on the first edge and that is between the first and second attachment structures.

[0006] In another example, a system for screen shaking is provided. The system includes an outer frame and an inner frame formed from lacing bars. The system includes attachment structures rigidly connecting the inner frame to external structural members and a projection screen having a viewing surface. The projection screen is configured to be partially wrapped around the outer frame. The system includes attachment hardware coupling the projection screen to the lacing bars and coupling the outer frame to the lacing bars. The outer frame comprising an extending element that extends away from the outer frame towards a middle of the projection screen, and the extending element is in contact with a backside of the projection screen. The system includes an actuator configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the extending element.

[0007] In yet another example, a system for screen shaking is provided. The system includes a projection screen having a viewing surface, a lacing bar, and attachment hardware coupling the projection screen to the lacing bar. The system includes a plurality of attachment structures rigidly connecting the lacing bar to external structural members. The attachment structures are connected to the lacing bar at different points along a first edge of the projection screen. The system includes a plurality of shaking actuators configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar. All of the shaking actuators in the system are positioned along the first edge of the projection screen.

[0008] In this manner, various aspects of the present disclosure provide for systems for screen shaking, and effect improvements in at least the technical fields associated with movie theaters, projection screens, and speckle reduction.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1A is a diagram of an actuator mounted to a lacing bar of a screen to shake the screen, according to some embodiments.

[0010] FIG. IB is a perspective view of the actuator of FIG. 1A, according to some embodiments.

[0011] FIG. 2 is a picture of rear of a screen mounted a screen frame with a lacing bar, according to some embodiments.

[0012] FIG. 3 is a diagram of a screen showing locations of screen shaking actuators and of structural mounting points for the lacing bar, according to some embodiments.

[0013] FIG. 4 is a diagram of a screen where the screen shaking actuators press on the edge of the screen, according to some embodiments.

[0014] FIG. 5 is a flow diagram illustrating a method for mitigating speckle, according to some embodiments.

[0015] FIG. 6 is a block diagram that shows examples of components of an apparatus capable of implementing various aspects of this disclosure.NOTATION AND NOMENCLATURE

[0016] Throughout this disclosure including in the claims, the expression “system” is used in a broad sense to denote a device, system, or subsystem.

[0017] Throughout this disclosure including in the claims, the term “processor” is used in a broad sense to denote a system or device programmable or otherwise configurable (e.g., with software or firmware) to perform operations on data (e.g., audio, or video or other image data). Examples of processors include a field-programmable gate array (or other configurable integrated circuit or chip set), a digital signal processor programmed and / or otherwise configured to perform pipelined processing on audio or other sound data, a programmable general purpose processor or computer, and a programmable microprocessor chip or chip set.

[0018] Throughout this disclosure including in the claims, the term “couples” or “coupled” (including “electrically coupled”) is used to mean either a direct or indirect connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections.

[0019] Throughout this disclosure including in the claims, numerous details are set forth, such as device configurations, timings, operations, and the like, in order to provide an understanding of one or more aspects of the present disclosure. It will be readily apparent to one skilled in the art that these specific details are merely exemplary and not intended to limit the scope of this application.DETAILED DESCRIPTION OF EMBODIMENTS

[0020] There have been efforts to mitigate subjective speckle. One approach is to use lower- gain screens, as the manufacturing techniques used for higher-gain screens also increase subjective speckle. However, this is often not a practical solution because the power and cost of the laser system increases as the screen gain decreases, and many applications require high gain screens.

[0021] A potentially less costly solution is screen shaking or screen vibration. Screen shaking changes the shape and location of the surface features over time, which in turn changes the spatial phase relationship, and thus the speckle pattern over time. This makes the speckle noise pattern change temporally as observed by a stationary observer, which reduces its overall visibility.

[0022] Shaking or vibrating the viewing area of a screen (such as a projection screen) to reduce artifacts can be achieved in different ways, including via physical, acoustic, or electromagnetic means. For instance, applying energy to voice coil actuators can cause the actuators to move in prescribed directions and cause at least portions of the screen to move (e.g., vibrate) accordingly.

[0023] Shaking or vibrating a screen becomes increasingly difficult as the size of the screen increases. Screens with widths of 50 feet, 60 feet, 100 feet, or larger may have a large damping force and traditional shaking mechanisms generally require actuator mechanisms that press directly on the screen’s viewing area. Additionally, certain materials used in screen construction have higher damping properties. As an example, vinyl projection screens typically have a high damping coefficient. In typical screen shaking systems, it is generally necessary to place vibrating actuators in many locations, spaced across the viewing area of the screen. One consequence of this geometry is that the waves emanating from each point tend to interfere constructively and destructively. These areas will have flat or no movement of the screen which results in no speckle reduction. These areas appear as veins of high speckle and can often be more distracting than uniform areas of high speckle. The likelihood of this interference goes up as the number of actuators increases, so fewer actuators can be beneficial.

[0024] As the damping force must be overcome to achieve sufficient speckle mitigation, there is a high risk of the actuators’ contact points on the screen to be visible - particularly with larger and higher gain screens (e.g., screen with a gain of 2.0 or more). Thus, there is a need for screen shaker systems, including actuators and mechanisms for coupling actuators to screens, that can shake the screen with sufficient force to achieve sufficient movement of the screen and thus achieve sufficient speckle reduction, but without causing poke-through artifacts.

[0025] Another challenge is to create enough screen movement to be effective at speckle reduction without causing excessive noise to the audience. To further complicate the challenge, HVAC pressure changes or opening and closing of exit doors in the auditorium and screen sagover the lifetime of the screen can cause the screen to bellow in or out by six or more inches. The variation is generally greatest in the middle of the screen. This variation of screen position is very difficult to accommodate by any vibration mechanism that is in direct contact with the back of the screen or that relies on being in close proximity to the back of the screen.

[0026] Waves generated from the edge of the screen that travel mostly or completely across the screen are very effective for reducing speckle. A mechanical actuator can shake the screen directly at the edge of the screen or indirectly by shaking the frame with enough force to generate waves that travel across the entire screen as opposed to a distributed array of shakers across the screen that propagate waves out from each device (and often canceling each other). The benefit of the traveling wave motion can be explained by an analogy with a jump rope. If one person holds one end of a jump rope and the other starts to move his end up and down, waves are easily generated from one end to the other. One flick of the wrist easily creates a traveling wave. In fact, it works best with some slack on the rope. The phenomenon is not reliant on high tension of the rope. Similarly, traveling waves across the screen are not reliant on tension of the screen. While it is counterintuitive to place the actuators far from the predominant viewing area, the traveling waves may be generated best from the edge.

[0027] By attaching actuators to the screen frame, ample force can be applied to produce waves that travel completely across the screen - even if the screen is large, high-gain, and / or built with high damping materials - with sufficient amplitude to mitigate speckle and without creating poke- through artifacts. Alternatively, ample force can be applied by actuators that are positioned directly on the screen but only at the very edge where the frame is also in direct contact with the screen so that the actuator’s contact patch(es) is indistinguishable from the contact point(s) of the frame and result(s) in minimal or no poke-through artifacts. Furthermore, any poke-through artifacts will only be present at the very edge of the screen where it is less consequential or entirely inconsequential to the quality of the viewing experience.

[0028] Shaking mechanisms distributed in the middle of the screen generally require a large number of distributed shaking mechanisms and struggle to apply sufficient force without creating poke-through artifacts. Having a large number of distributed shaking mechanisms also tends to result in areas of destructive interference between the mechanisms - which appear as veins of speckle. By attaching shaking mechanisms directly to the screen frame, or to the screen but near the frame, the number of shaking mechanisms can be reduced and the risk of destructive interference and speckle veins can be reduced. Additionally, the frequencies of the edge-mounted shaking mechanisms can be offset from each-other, to further reduce the likelihood of destructiveinterference (i.e., portions of the screen not moving and exhibiting speckle because waves from one or more shaking mechanisms destructively interfere).

[0029] Screens are often curved in the horizontal plane to create an effect of enveloping the audience. Screens configured this way are first tensioned in the vertical direction (along top and bottom edges of the screen frame) from the middle out to the sides, and then slightly tensioned in the horizontal direction (sides of the screen frame). This technique of tensioning the screen plus the force of gravity creates higher tension in the vertical direction of the screen. In such situations, screen shaking may be more effective when the actuators are placed along the bottom edge of the screen where they are also conducive to installation and service. Projection screens described herein have a viewing surface that may be, for example, a planar viewing surface, a curved viewing surface, a surface having at least partially a cylindrical curvature, or the like.

[0030] The appearance of speckle is dependent on viewing distance and luminance. Closer viewing distances and higher luminance generally result in higher perceived speckle. Screens with gain of greater than 1.0 have an associated hot spot where the luminance is highest at locations when the viewer is at an angle of reflection of the light from the screen equal to the angle of incidence of the projected light on the screen. Cinema screens typically have a gain of more than 2.0. The geometry of cinema auditoriums results in the hot spot being at different locations on the screen for different viewing positions. The worst location for the hot spot is generally in the front row. In most cases, the hot spot in the front row is directly in front of the viewer and the viewer is very close to the screen. This is a bad combination of distance and luminance.

[0031] Voice coils or unbalanced motors placed along the bottom edge of the screen may have the greatest effect near the bottom of the screen where the speckle problem is most challenging. Accessibility for installation and service of voice coils along the bottom edge of the screen is generally desirable over actuators that are placed high up in hard-to-reach locations. The viewing position from the middle rows is still close enough for the speckle to be a problem in the hot spot, but also close enough to the bottom edge of the screen frame such that the actuators mounted at the bottom edge still have a meaningful impact on speckle reduction. The viewing position from the back row is significantly far away from the screen such that less screen shaking is required at the hot spot location or top of the screen where the shakers are the farthest away.

[0032] There are generally two types of screen mounting techniques. The first screen type involves wrapping the screen around a fixed frame and tensioning the screen on the back side to some inboard frame structure. This first type of screen is often used to create an aesthetic of a floating screen that is mounted slightly off the back wall of the theater. The second screen type is involves lacing the screen to a frame that is larger than the screen. This type of mounting requiresa screen mask to conceal the frame, lacing and eyelets of the screen. Both screen types may use stretchable cord to tension the screen. Both screen types can be spaced off the front wall of the theater to accommodate speakers and other equipment.

[0033] One or more actuators can be attached directly to the frame of the screen, or a lacing bar of the screen, to shake the screen indirectly with ample force to overcome screen damping forces. An integrated flexible portion of the frame can be designed to maximize the transfer of vibration from the actuator. Speckle reducing waves are thus generated on the screen that travel across the entire screen. The vibrating mechanism may be a voice coil or an unbalanced motor, etc. These designs benefit from not needing to touch the back of the screen and thus avoid causing visible artifacts on the front side of the screen. The mechanisms generally do not require adjustment to compensate for bellowing of screen due to changes in air pressure due to HVAC cycles, exit doors opening and closing or screen sag over time. A relatively low number of shakers can transmit vibrations through some or all of the frame structure - since a much higher force can be applied at the frame or edge of the screen where it does not create a poke-through artifact on the viewing side. Fewer shaking devices result in lower chances of interference that cause speckle veins. Multiple mechanisms along one edge may be in phase to create constructive interference and increase the amplitude of the wave. The frequencies of two or more devices may be offset to prevent interference of the waves. The frequencies of the device(s) may be swept over a range to prevent interference of the waves. The screen shaking mechanisms may be able to be retrofitted onto existing screens.

[0034] Embodiments of the present disclosure use arrangements of screen shaking mechanisms mounted directly to a screen frame, or mounted to the screen but only near the frame, which can be arranged to reduce or eliminate speckle while reducing or eliminating any visible indentations on a screen.

[0035] Many embodiments of the present disclosure are technologically possible to implement to achieve the foregoing solutions given the following descriptions. It will be apparent to those of ordinary skill in the art from the present disclosure how to implement them.

[0036] FIG. 1A is a diagram of a screen shaking actuator mounted to a lacing bar of a screen 100. As shown in FIG. 1 A, an actuator 110 may be mounted to the lacing bar 102 of screen 100. FIG. IB is a perspective view of the actuator 110. The actuator 110 may include a component 112 that is attached to lacing bar 102. The lacing bar 102 and the actuator 110 may be situated on a backside of the screen 100. The component 112 may be rigidly fixed to the lacing bar 102, such that movement generated by the actuator 110 in response to electrical signals is converted into motion of the lacing bar 102. The actuator 110 may be configured to shake (i.e., move) the lacingbar 102 in a direction normal to the plane of the screen 100 (e.g., shake along axis X of FIG. IB). Such movement causes a vector normal to the plane of the screen 100 to vary in direction. The actuator 110 may not be otherwise mounted to a structure (i.e., may be free floating), but may have sufficient mass that actuation of the actuator 110 is able to push and pull on the screen 100 and induce sufficient screen shaking to mitigate speckle. In some alternative embodiments, the actuator 110 may be rigidly mounted, such as on side 114, to a fixed structural member (e.g., a static structural member, building framing, or the like). The actuator 110 has a diameter of L, such as, for example, 2.5 inches, 3 inches, 3.5 inches, or the like.

[0037] FIG. 2 is a picture of the rear of a laced screen 200 - in which the screen 200 is wrapped around an outer frame (not shown), then pulled taught with an inner frame 202 (often referred to as a lacing bar). The lacing bar 202 of the screen 200 may be rigidly secured at attachment point 204. Because of the typical construction of the lacing bar 202, the lacing bar 202 is generally rather flexible along axis 203 (i.e., directions normal to the plane of the screen) - especially in areas further from attachment points such as attachment point 204. FIG. 2 also illustrates how the outer frame is mounted to the lacing bar 202 using stretchable cords 205 or other such mechanisms, while the lacing bar 202 is mounted to rigid structure at attachment point 204 (i.e., the lacing bar 202 is mounted to fixed building structure, while the outer frame is suspended off the lacing bar 202). While the figures illustrated herewith illustrate mounting a screen 200 to the lacing bar 202 with stretchable cords 205, in general any desired attachment hardware may be used including, but not limited to, springs, stretchable cord, non- stretchable cord, hooks, wire, clips, brackets, screws, adhesives, bolts, nuts, or other fasteners or any desired combination thereof.

[0038] FIG. 3 is a diagram of a screen system 300 that may include a screen 302 wrapped around an outer frame 304, and then tensioned to a lacing bar 306. FIG. 3 illustrates that, in some embodiments of the present invention, screen shaking actuators 310 (which may be voice coils) are mounted to the lacing bar 306 along the bottom of screen 302, and at positions that are between mounting points 312. The actuators 310 may be substantially similar to the actuators 110 of FIG. 1. The mounting points 312 (e.g., attachment structures) are positions where the lacing bar 306 is rigidly or semi-rigidly mounted to structural member(s) that support the entire screen system 300. In other words, the mounting points 312 are positions where the lacing bar 306 is held in place with attachments to structural members (where said structural members may be affixed to, or be a part of, a building’s structural members). As shown in FIG. 3, it may be desirable to position actuators 310 between the mounting points 312, as the lacing 306 is flexible between the mounting points 312 - enabling the actuators 310 to sufficiently shake the screen to reduce speckle. The screen 302 may be significantly less flexible, or immobile, at or near the mounting points 312. Inthe example of FIG. 3, the mounting points 312 include a first mounting point 312A on a first side (or edge) of the screen 302, a second mounting point 312B on a second side (e.g., the bottom) of the screen 302, a third mounting point 312C on the second side of the screen 302, a fourth mounting point 312D on the second side of the screen 302, a fifth mounting point 312E on the second side of the screen 302, and a sixth mounting point 312F on a third side of the screen 302. In further examples, additional mounting points 312 may be provided, and mounting points 312 may be provided along a fourth side (e.g., the top) of the screen 302. Additionally, in the example of FIG. 3, an actuator 310 is situated between the second mounting point 312B and the third mounting point 312C, and an actuator 310 is situated between the fourth mounting point 312D and the fifth mounting point 312E. In other examples, multiple actuators 310 may be situated between mounting points 312 (for example, another actuator 310 may be situated between the second mounting point 312B and the third mounting point 312C). Additionally, in other examples, actuators 310 may be situated on sides of the screen 302 other than, or in addition to, the bottom of the screen 302.

[0039] In some alternative embodiments, actuators 310 may be placed along one or both sides of the screen 302, or along the top side of the screen 302 - either in addition to or instead of having actuators along the bottom of the screen 302. While bottom-mounted actuators 310 may be more serviceable and effective at hot spot reduction in general, there may be benefits to mounting actuators 310 along the top and / or sides in certain situations. As an example, if a cinema were laid out with the projector below the first row rather than above the last row, top-mounting the actuators 310 may provide more hot spot reduction than bottom mounting. As another example, if a cinema utilized one or more projectors on one or more sides, mounting the actuators 310 on the side(s) where the projector(s) is mounted may provide more hot spot reduction than bottom mounting.

[0040] Note that FIG. 3 illustrates only a portion of lacing bar 306, and the upper portions of lacing bar 306 are omitted from the illustration. In practice, lacing bar 306 may extend around the entire perimeter of the screen 302.

[0041] While FIG. 3 illustrates just two actuators 310, each being between a different pair of mounting points 312, this is merely illustrative and other configurations may be implemented. As examples, there may be multiple actuators 310 between pairs of mounting points 312, there may be one or more actuators 310 between every pair of mounting points 312 along the bottom edge, there may be one or more actuators 310 along other edges such as the sides and / or top, there may more or fewer mounting points 312 along any edge, etc.

[0042] FIG. 4 is a diagram of a screen 401 where the screen shaking actuators press on the edge of the screen 401. As shown in FIG. 4, an actuator 400 may be mounted on a rigid shakingarm 402 (e.g., an extending element), where the shaking arm 402 extends outwardly from the outer frame 410. The actuator 400 may be substantially similar to the actuator 110 of FIG. 1. The shaking arm 402 may be an integral part of the outer frame 410, or may be a separate component attached to the outer frame 410 (as illustrated in FIG. 4). In some embodiments, a buffer element 404 (such as a piece of foam, a sponge, or other material) may be placed between the shaking arm 402 and the screen 401 to reduce the visibility of poke-through artifacts. In other embodiments, buffer element 404 may be omitted. In some embodiments, additional filler-segments 406 may be provided that extend partly or fully across the bottom edge of the screen 401 in order to help conceal the contact patch of shaking arm 402. The filler segments 406 may, in some embodiments, extend the width of shaking arm 402 such that shaking arm 402 extends mostly or entirely between adjacent rigid mounting points. As an example, such as in the context of FIG. 3, the filler segments 406 associated with a given actuator 310 may extend along the bottom of the screen 302 mostly or entirely from the mounting point 312 on one side of the given actuator 310 to the mounting point 312 on the other side of the given actuator 310. In other embodiments, filler segments 406 may be a single piece that extends mostly or all the way across the bottom of the screen 302, 401 and is coupled to multiple actuators 310, 400.

[0043] As shown in the FIG. 4 embodiment, the shaking arm 402 may extend inwardly from the outer frame 410. In some embodiments, the shaking arm 402 may press only on the outermost portions of the screen 401. As an example, the shaking arm 402 may extend inwardly less than the lacing bar (shown, but not labeled in FIG. 4).

[0044] While FIGS. 1-4 generally illustrate screens of the first screen type (a screen wrapped around a frame and then tensioned to an inboard frame structure), the embodiments described herein can also be implemented in screens of the second screen type (where screens are laced to a frame larger than the screen). In screens of the second screen type, the actuators can still be mounted directly to the lacing bar at positions between where that lacing bar is mounted to structural or framing members. In some embodiments, the actuators can be attached to the lacing itself (for screens of both the first and second types) and can shake the screen by shaking the lacing. Significant screen movement can be achieved with elastic lacing material such as commonly available shock cord. Similarly, the actuators can still be configured to press directly on the screen, but near the frame, but utilizing elements such as the shaking arm 402 and, if desired, the filler segments 406 of FIG. 4. When the embodiment of FIG. 4 is implemented in screens of the second screen type, it should be noted that the outer frame 410 would be the “lacing bar” (i.e., the bar the screen is laced and tensioned to), but the functionality would otherwise be similar.Methods

[0045] FIG. 5 is a flow diagram illustrating a method 500 for mitigating speckle, according to some embodiments. One or more of the functions of the method 500 may be performed by a computerized apparatus or system. Means for performing the functionality illustrated in one or more of the steps shown in FIG. 5 may include hardware and / or software components of such computerized apparatus or system, such as, for example, a device, a computer system, or a computer-readable apparatus including a storage medium storing computer-readable and / or computer-executable instructions that are configured to, when executed by a processor apparatus, cause the at least one processor apparatus or another apparatus to perform the operations. Example components of a computerized apparatus or system are illustrated in FIG. 6, which are described in more detail below. A controller may be one example of the computerized apparatus or system.

[0046] It should also be noted that the operations of the method 500 may be performed in any suitable order, not necessarily the order depicted in FIG. 5. Further, the method 500 may include additional or fewer operations than those depicted in FIG. 5 to perform the speckle mitigation.

[0047] In some embodiments, the speckle includes a plurality of interference artifacts on a projection screen. In some embodiments, the projection screen may include actuators mounted to a lacing bar between structural mounting points or pressing on the screen near an outer frame member.

[0048] At step 502, the method 500 may include generating and transmitting one or more signals to one or more actuator(s). In some embodiments, the actuator(s) may be directly coupled to a lacing bar between structural mounting points of that lacing bar. For example, with reference to FIG. 3, the actuators 310 are directly coupled to lacing bar 306 between mounting points 312. In some other embodiments, the actuator(s) may directly press on an edge of the screen, near an outer frame member (i.e., a lacing bar in a screen of the second type, or an outer frame member in a screen of the first type). For example, with reference to FIG. 4, the actuator 400 presses on an edge of the screen 401 near outer frame 410.

[0049] In some embodiments, the one or more signals may be generated by a controller. In some implementations, the one or more signals may be transmitted to a power supply configured to drive current through the electromagnetic actuator, e.g., through its coils. In some cases, the power supply may be external to the electromagnetic actuator, or interior to and be part of the electromagnetic actuator. In some implementations, the one or more signals may be transmitted directly to the electromagnetic actuator. The electromagnetic actuator may have an interface, a processor, and / or memory electrically coupled to the core and / or the coils to receive signals from at least the controller and operate according to the signals.

[0050] At step 504, the method 500 may include coupling motion from the actuator into the projection screen based on the transmitted one or more signals. In some embodiments, the controller may send signals configured to cause an electrical current (e.g., via the power supply) to flow through coils or traces associated with the electromagnetic actuator. The motion of the projection screen may be an oscillating motion at a particular frequency (e.g., 30-36 Hz) and / or at a particular displacement (e.g., 1 mm). In some embodiments, the motion of the projection screen may include multiple frequencies. For instance, the motion may include a motion at a first frequency at a first location of the projection screen, and a motion at a second frequency at a second location of the projection screen, the first and second frequencies comprising different frequencies selected from a range.

[0051] In some embodiments, the motion of the projection screen may include a motion in a direction normal to the surface of the projection screen. In some embodiments, the motion of the projection screen may include a motion in a direction within the plane of the surface of the projection screen.Apparatus

[0052] FIG. 6 is a block diagram that shows examples of components of an apparatus capable of implementing various aspects of this disclosure. As with other figures provided herein, the types and numbers of elements shown in FIG. 6 are merely provided by way of example. Other implementations may include more, fewer and / or different types and numbers of elements. According to some examples, the apparatus 600 may be configured for performing at least some of the methods disclosed herein. In some implementations, the apparatus 600 may be, or may include, a device configured to control an electromagnetic actuator for causing motion of a projection screen. In some implementations, the apparatus 600 may be, or may include, a device that includes an electromagnetic actuator for causing motion of the projection screen.

[0053] In this example, the apparatus 600 includes an interface system 605 and a control system 606. The interface system 605 may, in some implementations, be configured for communication with one or more other devices. The interface system 605 may, in some implementations, be configured for exchanging control information and associated data. The control information and associated data may, in some examples, pertain to one or more software applications that the apparatus 600 is executing.

[0054] The interface system 605 may include one or more network interfaces and / or one or more external device interfaces, such as one or more universal serial bus (USB) interfaces. According to some implementations, the interface system 605 may include one or more wirelessinterfaces. In some examples, the interface system 605 may include one or more interfaces between the control system 606 and a memory system, such as the optional memory system 615 shown in FIG. 6. However, the control system 606 may include a memory system in some instances. The interface system 605 may, in some implementations, be configured for receiving signal input or providing signal to, e.g., an actuator or a power supply.

[0055] The control system 610 may, for example, include a general purpose single- or multichip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, and / or discrete hardware components. A controller apparatus may be an example of the control system 610 or a portion of the control system 610.

[0056] In some implementations, the control system 610 may reside in more than one device. For example, in some implementations a portion of the control system 610 may reside in a device within one of the environments depicted herein and another portion of the control system 610 may reside in a device that is outside the environment, such as a server, a mobile device (e.g., a smartphone or a tablet computer), etc. In other examples, a portion of the control system 610 may reside in a device within one environment and another portion of the control system 610 may reside in one or more other devices of the environment. For example, a portion of the control system 610 may reside in a device that is implementing a cloud-based service, such as a server, and another portion of the control system 610 may reside in another device that is implementing the cloudbased service, such as another server, a memory device, etc. The interface system 605 also may, in some examples, reside in more than one device.

[0057] In some implementations, the control system 610 may be configured for performing, at least in part, the methods disclosed herein. According to some examples, the control system 610 may be configured to cause an electromagnetic actuator to generate an shaking force by transmitting or receiving control signals, or the like.

[0058] Some or all of the methods described herein may be performed by one or more devices according to instructions (e.g., software) stored on one or more non-transitory media. Such non- transitory media may include memory devices such as those described herein, including but not limited to random access memory (RAM) devices, read-only memory (ROM) devices, etc. The one or more non-transitory media may, for example, reside in the optional memory system 615 shown in FIG. 6 and / or in the control system 610. Accordingly, various innovative aspects of the subject matter described in this disclosure can be implemented in one or more non-transitory media having software stored thereon. The software may, for example, include instructions for determining gain parameters, applying gain transition functions, determining inverse gaintransition functions, applying inverse gain transition functions, distribution bits for gain control with respect to a bitstream, etc. The software may, for example, be executable by one or more components of a control system such as the control system 610 of FIG. 6.

[0059] Some aspects of present disclosure include a system or device configured, e.g., programmed, to perform one or more examples of the disclosed methods, and a tangible computer readable medium, e.g., a disc, which stores code for implementing one or more examples of the disclosed methods or steps thereof. For example, some disclosed systems can be or include a programmable general purpose processor, digital signal processor, or microprocessor, programmed with software or firmware and / or otherwise configured to perform any of a variety of operations on data, including an embodiment of disclosed methods or steps thereof. Such a general purpose processor may be or include a computer system including an input device, a memory, and a processing subsystem that is programmed (and / or otherwise configured) to perform one or more examples of the disclosed methods (or steps thereof) in response to data asserted thereto.

[0060] Some embodiments may be implemented as a configurable (e.g., programmable) digital signal processor (DSP) that is configured (e.g., programmed and otherwise configured) to perform required processing on audio signal(s), including performance of one or more examples of the disclosed methods. Alternatively, embodiments of the disclosed systems (or elements thereof) may be implemented as a general purpose processor, e.g., a personal computer (PC) or other computer system or microprocessor, which may include an input device and a memory, which is programmed with software or firmware and / or otherwise configured to perform any of a variety of operations including one or more examples of the disclosed methods. Alternatively, elements of some embodiments of the inventive system are implemented as a general purpose processor or DSP configured (e.g., programmed) to perform one or more examples of the disclosed methods, and the system also includes other elements. The other elements may include one or more loudspeakers and / or one or more microphones. A general purpose processor configured to perform one or more examples of the disclosed methods may be coupled to an input device. Examples of input devices include, e.g., a mouse and / or a keyboard. The general purpose processor may be coupled to a memory, a display device, etc.

[0061] Another aspect of present disclosure is a computer readable medium, such as a disc or other tangible storage medium, which stores code for performing, e.g., by a coder executable to perform, one or more examples of the disclosed methods or steps thereof.

[0062] While specific embodiments of the present disclosure and applications of the disclosure have been described herein, it will be apparent to those of ordinary skill in the art that manyvariations on the embodiments and applications described herein are possible without departing from the scope of the disclosure described and claimed herein. It should be understood that while certain forms of the disclosure have been shown and described, the disclosure is not to be limited to the specific embodiments described and shown or the specific methods described.

[0063] Various aspects of the present invention may be appreciated from the following enumerated example embodiments (EEEs):

[0064] EEE1. A system for screen shaking, the system comprising: a projection screen having a viewing surface; a lacing bar; first and second attachment structures rigidly connecting the lacing bar to external structural members, wherein the first and second attachment structures are connected to the lacing bar at first and second points along a first edge of the projection screen; and an actuator configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar at a position that is on the first edge and that is between the first and second attachment structures.

[0065] EEE2. The system of EEE1, further comprising: a third attachment structure rigidly connecting the lacing bar to the external structural members, wherein the third attachment structures is connected to the lacing bar at a third point along the first edge of the projection screen; and an additional actuator configured to vibrate in the direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar at an additional position that is on the first edge and that is between the first and third attachment structures.

[0066] EEE3. The system of EEE 1 or EEE2, wherein the first edge comprises a bottom edge of the projection screen.

[0067] EEE4. The system of EEE1 or EEE2, wherein the first edge comprises a top edge of the projection screen.

[0068] EEE5. The system of EEE1 or EEE2, wherein the first edge comprises a side edge of the projection screen.

[0069] EEE6. The system of EEE1, further comprising: third and fourth attachments structure rigidly connecting the lacing bar to external structural members, wherein the third and fourth attachment structures are connected to the lacing bar at third and fourth points, respectively, along a second edge of the projection screen; and an additional actuator configured to vibrate in the direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar at an additional position that is on the second edge and that is between the third and fourth attachment structures.

[0070] EEE7. The system of any one of EEE1 to EEE6, wherein the viewing surface comprises a planar vie wing surface.

[0071] EEE8. The system of any one of EEE 1 to EEE6, wherein the viewing surface comprises a curved viewing surface.

[0072] EEE9. The system of any one of EEE1 to EEE6, wherein at least a portion of the viewing surface has a cylindrical curvature.

[0073] EEE10. The system of any one of EEE1 to EEE9, wherein the attachment hardware comprises at least one selected from a group consisting of springs, stretchable lacing, and hooks.

[0074] EEE11. A system for screen shaking, the system comprising: an outer frame; an inner frame formed from lacing bars; attachment structures rigidly connecting the inner frame to external structural members; a projection screen having a viewing surface, wherein the projection screen is configured to be partially wrapped around the outer frame; attachment hardware coupling the projection screen to the lacing bars and coupling the outer frame to the lacing bars; wherein the outer frame comprises an extending element that extends away from the outer frame towards a middle of the projection screen, and wherein the extending element is in contact with a backside of the projection screen; and an actuator configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the extending element.

[0075] EEE 12. The system of EEE11, wherein the extending element is an integral part of the outer frame.

[0076] EEE13. The system of EEE11, wherein the extending element is rigidly connected to the outer frame.

[0077] EEE14. The system of any one of EEE11 to EEE13, wherein the extending element comprises a rigid structure in contact with the backside of the projection screen.

[0078] EEE15. The system of any one of EEE11 to EEE14, wherein the extending element is positioned along a bottom edge of the projection screen.

[0079] EEE16. The system of any one of EEE11 to EEE15, wherein, when viewed from the frontside of the screen, portions of the projection screen in contact with the extending element appear visually indistinguishable from portions of the projection screen not in contact with the extending element.

[0080] EEE17. The system of any one of EEE11 to EEE16, wherein the inner frame is separated from the outer frame by a first distance, wherein the extending element extends a second distance towards the middle of the projection screen, and wherein the second distance is less than the first distance.

[0081] EEE18. A system for screen shaking, the system comprising: a projection screen having a viewing surface; a lacing bar; attachment hardware coupling the projection screen to the lacing bar; a plurality of attachment structures rigidly connecting the lacing bar to external structuralmembers, wherein the attachment structures are connected to the lacing bar at different points along a first edge of the projection screen; and a plurality of shaking actuators configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar, wherein all of the shaking actuators in the system are positioned along the first edge of the projection screen.

[0082] EEE19. The system of EEE18, wherein the first edge comprises a bottom edge of the projection screen.

[0083] EEE20. The system of EEE18 or EEE19, wherein each of the shaking actuators is positioned between a different pair of attachment structures from the plurality of attachment structures.

[0084] EEE21. The system of EEE18 or EEE19, wherein the plurality of shaking actuators include at least two shaking actuators positioned between a pair of attachment structures along the first edge of the projection screen.

[0085] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.

[0086] All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

[0087] The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments incorporate more feature than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

Claims

CLAIMS1. A system for screen shaking, the system comprising: a projection screen having a viewing surface; a lacing bar; first and second attachment structures rigidly connecting the lacing bar to external structural members, wherein the first and second attachment structures are connected to the lacing bar at first and second points along a first edge of the projection screen; and an actuator configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar at a position that is on the first edge and that is between the first and second attachment structures.

2. The system of claim 1 , further comprising: a third attachment structure rigidly connecting the lacing bar to the external structural members, wherein the third attachment structures is connected to the lacing bar at a third point along the first edge of the projection screen; and an additional actuator configured to vibrate in the direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar at an additional position that is on the first edge and that is between the first and third attachment structures.

3. The system of claim 1 or claim 2, wherein the first edge comprises a bottom edge of the projection screen or comprises a top edge of the projection screen or comprises a side edge of the projection screen.

4. The system of claim 1 , further comprising: third and fourth attachments structure rigidly connecting the lacing bar to external structural members, wherein the third and fourth attachment structures are connected to the lacing bar at third and fourth points, respectively, along a second edge of the projection screen; and an additional actuator configured to vibrate in the direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar at an additional position that is on the second edge and that is between the third and fourth attachment structures.

5. The system of any of claims 1 to 4, wherein the viewing surface comprises a planar viewing surface or a curved viewing surface or wherein at least a portion of the viewing surface has a cylindrical curvature.

6. The system of any of claims 1 to 5, wherein the attachment structure comprises at least one selected from a group consisting of non-stretchable cord, hooks, clips, brackets, screws, bolts, and nuts.

7. The system of any of claims 1 to 6, wherein the system further comprises a projector, wherein the actuator is configured to be mounted on a side of the projection screen where the projector is configured to be mounted.

8. The system of any of claims 1 to 7, wherein the system further comprises: a plurality of attachment structures rigidly connecting the lacing bar to external structural members, wherein the attachment structures are connected to the lacing bar at different points along the first edge of the projection screen; and a plurality of shaking actuators configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the lacing bar, wherein all of the shaking actuators in the system are positioned along the first edge of the projection screen.

9. The system of claim 8, wherein each of the shaking actuators is positioned between a different pair of attachment structures from the plurality of attachment structures.

10. The system of claim 8, wherein the plurality of shaking actuators includes at least two shaking actuators positioned between a pair of attachment structures along the first edge of the projection screen.

11. A system for screen shaking, the system comprising: an outer frame; an inner frame formed from lacing bars; attachment structures rigidly connecting the inner frame to external structural members;a projection screen having a viewing surface, wherein the projection screen is configured to be partially wrapped around the outer frame; attachment hardware coupling the projection screen to the lacing bars and coupling the outer frame to the lacing bars; wherein the outer frame comprises an extending element that extends away from the outer frame towards a middle of the projection screen, and wherein the extending element is in contact with a backside of the projection screen; and an actuator configured to vibrate in a direction perpendicular to the viewing surface and being rigidly coupled to the extending element.

12. The system of claim 11, wherein the extending element is an integral part of the outer frame or wherein the extending element is rigidly connected to the outer frame.

13. The system of claim 11 or claim 12, wherein the extending element comprises a rigid structure in contact with the backside of the projection screen and / or wherein the extending element is positioned along a bottom edge of the projection screen.

14. The system of any of claims 11 to 13, wherein, when viewed from the frontside of the screen, portions of the projection screen in contact with the extending element appear visually indistinguishable from portions of the projection screen not in contact with the extending element.

15. The system of any of claims 11 to 14, wherein the inner frame is separated from the outer frame by a first distance, wherein the extending element extends a second distance towards the middle of the projection screen, and wherein the second distance is less than the first distance.

16. The system of any of claims 1 to 15, wherein the projection screen is configured to have an oscillating motion including a motion at a first frequency at a first location of the projection screen, and a motion at a second frequency at a second location of the projection screen, the first and second frequencies comprising different frequencies selected from a range.

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