Projection screen speckle reduction

Abstract

A method and apparatus for reducing speckle on an image projection screen is disclosed. Non-contact rocking or vibration of the projection screen can be achieved using lightweight materials. For example, a magnetic material such as iron powder (suspended in a binder material) can be coated on the screen, and one or more electromagnetic actuators can be positioned at a distance to generate a magnetic field that induces the vibration. A controller can generate and transmit a signal to the electromagnetic actuator, the signal configured to generate a magnetic field that causes the screen to vibrate at one or more prescribed frequencies. Such motion can at least partially mitigate the visual perceptibility of speckle.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 362,624, filed April 7, 2022, and European Application No. 22167096.1, filed April 7, 2022, all of which are incorporated by reference in their entireties.

[0002] 1. Field of disclosure The present disclosure relates generally to the field of image projection, and more specifically to enhancing displayed images on laser projection screens, and techniques disclosed herein are directed to mitigating speckle artifacts on the projection screen. [Background technology]

[0003] 2. Related Technologies Speckle refers to a visual artifact that can be perceived by an observer as a granular interference pattern. Speckle can occur when a rough surface (e.g., a projection screen) is illuminated by coherent light (e.g., a laser beam). The speckle pattern observable by an observer in the image plane of the surface is known as the "subjective speckle pattern". Subjective speckle is an artifact that appears as a static intense noise pattern. It does not necessarily occur on the projection screen itself, but between the screen and the observer's eye. Each observer may see a different subjective speckle pattern, although the overall characteristics may be similar. The subjective speckle pattern can and does change depending on the viewing conditions, such as the observer's motion, the size of the lens aperture, or the position of the imaging system.

[0004] While objective speckle caused by surfaces can often be addressed with fixed modifications to the optical design, subjective speckle is caused by interference between screen surface features and the human eye. Modifications to the projector optical system are therefore often ineffective, especially in large screen applications. Subjective speckle is highly annoying to observers, as the patterns can create visual noise and cause non-uniform reflectance across the screen. Subjective speckle thus plagues providers of projection and other display systems that utilize laser illumination due to the coherence of the laser light. Summary of the Invention [Means for solving the problem]

[0005] In one aspect of the present disclosure, a method for reducing speckle is disclosed. In some embodiments, the method may include generating and transmitting one or more signals to an electromagnetic actuator.

[0006] In some variations, the electromagnetic actuator is positioned at a distance from the magnetic material. In some variations, the magnetic particles are fixed in an extensible binder and disposed on the projection screen. In some variations, the electromagnetic actuator generates a magnetic field in response to one or more transmitted signals. In some variations, the generated magnetic field interacts with the magnetic material to move the projection screen to at least partially mitigate the visual perceptibility of speckle.

[0007] In another aspect of the present disclosure, a method is disclosed for obtaining a projection screen that can be vibrated by a non-contact magnetic driver to at least partially reduce the visual perceptibility of speckle. In some embodiments, the method can include applying a magnetic material to at least a portion of the projection screen.

[0008] In some variations, applying the magnetic material includes at least one of: coating at least a portion of the projection screen with an extensible binder, wherein the magnetic particles are fixed in the binder; fixing one or more sheets of the magnetic material in a roll form having a thickness of less than 0.1 mm; depositing the magnetic particles substantially uniformly across the projection screen; or spatially positioning the magnetic particles at a first non-zero density on a first portion of the projection screen and at a second non-zero density different from the first density on a second portion of the projection screen.

[0009] In another aspect of the present disclosure, a system for projection screen shaking is disclosed. In some embodiments, the system may include a projection screen including a magnetic material secured in an extensible binder; at least one electromagnetic actuator disposed at a distance from the screen and configured to vibrate the projection screen via a magnetic field; and a controller configured to signal communicate with the at least one electromagnetic actuator, the controller configured to generate and send one or more signals to the at least one electromagnetic actuator to cause the at least one electromagnetic actuator to generate the magnetic field, the generated magnetic field interacting with the magnetic material to vibrate the projection screen.

[0010] In another aspect of the present disclosure, a projection screen is disclosed. In some embodiments, the projection screen may include magnetic particles arranged in a spatial pattern on the projection screen, the magnetic particles being suspended in an expandable binder and affixed to at least a portion of the projection screen or coated onto at least a portion of the projection screen. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of an electromagnetic actuator useful for generating a magnetic field, thereby affecting nearby magnetic objects, according to some embodiments.

[0012] [Diagram 2] 1A-E show different variations of a pattern of magnetic material disposed on a projection screen.

[0013] [Diagram 3] 1 is a diagram of an electromagnetic actuator in a horseshoe configuration positioned relative to a field of magnetic particles, according to some embodiments.

[0014] [Figure 4] FIG. 1 is a diagram of a configuration of a non-contact electromagnetic actuator positioned stationary relative to a screen.

[0015] [Diagram 5] 1 illustrates a cross-sectional view of a projection screen configured to vibrate orthogonal to the plane of the screen, according to some embodiments.

[0016] [Figure 6] FIG. 8 shows a diagram of a configuration of a screen positioned relative to a current carrying circuit, useful for realizing a projection screen arrangement such as that shown in FIG. 5 or FIG. 7.

[0017] [Figure 7] 1 shows a cross-sectional view of a projection screen arrangement configured to vibrate laterally relative to the plane or surface of the screen, according to some embodiments.

[0018] [Figure 8] 1 is a flow diagram illustrating a method for reducing speckle, according to some embodiments.

[0019] [Figure 9] 1 is a flow diagram illustrating a method for obtaining a projection screen configured to enable speckle reduction, according to some embodiments.

[0020] [Figure 10]FIG. 1 is a block diagram illustrating example components of an apparatus capable of implementing various aspects of the disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Notation and Nomenclature Throughout this disclosure, including the claims, the term "system" is used broadly to denote a device, system, or subsystem.

[0022] Throughout this disclosure, including the claims, the term "processor" is used broadly to denote a system or device that is programmable or otherwise configurable (e.g., with software or firmware) to perform operations on data (e.g., audio, video, or other image data). Examples of processors include field programmable gate arrays (or other configurable integrated circuits or chipsets), digital signal processors programmed and / or otherwise configured to perform pipeline processing on audio or other sound data, programmable general-purpose processors or computers, and programmable microprocessor chips or chipsets.

[0023] Throughout this disclosure, including the claims, the terms "couple" or "coupled" (including "electrically coupled") are used to mean either a direct connection or an indirect connection. Thus, when a first device couples to a second device, the connection may be through a direct connection or through an indirect connection via other devices and connections.

[0024] Detailed Description of the Embodiments Efforts have been made to reduce subjective speckle. One approach is to use lower gain screens, since the manufacturing techniques used for higher gain screens also increase subjective speckle. However, this is often not a practical solution, since the power and cost of the laser system increase as the screen gain decreases, and many applications require high gain screens.

[0025] A potentially less costly solution is screen shaking or screen vibration. Screen vibration changes the shape and position of surface features over time, which in turn changes the spatial phase relationships and thus the speckle pattern over time. This causes the speckle noise pattern observed by a stationary observer to vary in time, reducing its overall visibility.

[0026] Shaking or vibrating a screen (such as a projection screen) to reduce artifacts can be accomplished in different ways, including via physical, acoustic, or electromagnetic means. For example, applying energy to an electromagnetic actuator can cause the actuator to move in a defined direction and move (e.g., vibrate) said at least a portion of the screen accordingly. However, if care is not taken, the physical components used to shake or vibrate the screen can create their own visible artifacts on the screen, such as visible dents.

[0027] Embodiments of the present disclosure use an arrangement of magnetic materials that can be configured to reduce or eliminate visible dips on the screen.

[0028] Given the following description, many embodiments of the present disclosure can be technically implemented to achieve the aforementioned solutions, and it will be clear to those skilled in the art how to implement them from the present disclosure.

[0029] FIG. 1 is a simplified diagram of an electromagnetic actuator 100 useful for generating a magnetic field and thereby affecting a nearby magnetic object, according to some embodiments. The electromagnetic actuator 100 can include a core 102 having a coil 104 wound around the core. For example, the core 102 is a rod-shaped magnetic material having a winding 106 wound around it. The magnetic material can be, for example, a material that has magnetic properties similar to iron and can be permanently magnetized. The core 108 can be fixed to a structure 108, for example, a wall, a platform, a part of a larger actuation system. In some cases, such a structure can be fixed to another structure and / or can be stationary or movable along with the core 102. In some variations, the core can be other shapes or configurations, such as rectangular or toroidal (with a gap), or a "horseshoe" configuration (with parallel and / or non-parallel sides).

[0030] In some implementations, the power source 110 may pass a current through the coil 104, thereby generating a magnetic field that can repel or attract other magnetic elements (from a distance d) depending on the direction of the current. That is, a magnetic field having a first direction may be generated when the current through the coil 104 travels from path 106a to 106b, and a magnetic field having a second direction opposite to the first direction may be generated when the current through the coil 104 travels from path 106b to 106a. The core 102 may be influenced by the magnetic field and generate an induced magnetic field having a directional electromotive force (e.g., magnetic force 114) according to at least Faraday's law of electromagnetic induction. Thus, the magnetic force 114 may be generated to affect an object (e.g., screen 116) across a distance d depending on the direction of the current. FIG. 1 shows an example of a current flow in a first direction. The amount, frequency, and duration of the current generated by the power source 110 may be driven or controlled by one or more signals generated by and transmitted from the controller 112.

[0031] In some embodiments, the power source 110 may be part of the electromagnetic actuator 100 (e.g., located in the same chassis or structure as the actuator). In some embodiments, the power source 110 may be external to the electromagnetic actuator 100. In some embodiments, the controller 112 may be part of the electromagnetic actuator 100 or may be external to the electromagnetic actuator 100. In some cases, the electromagnetic actuator 100 may include an interface, processor, and / or memory electrically coupled to the core 102 and / or coils 104 to receive signals from at least the controller 112 and act according to the signals.

[0032] This disclosure describes a non-contact screen vibration method and apparatus that reduces or eliminates visible dimples on the screen. More specifically, this disclosure describes an electromagnetic actuator that can operate without contacting a screen coated with a magnetic material 118, which avoids adding significant mass to the screen. In some embodiments, an air gap or dielectric material exists between such an electromagnetic actuator 100 and the screen 116, which allows direct physical contact between the actuator and the screen to be avoided.

[0033] In some embodiments, the magnetic material may include a ferromagnetic material. A ferromagnetic material has a large positive magnetic susceptibility to an external magnetic field and essentially has a substantially parallel magnetic alignment of adjacent atoms. It can retain its magnetic properties after the external field is removed. Examples of ferromagnetic materials include iron, nickel, and cobalt. Other examples include gadolinium, neodymium, and alnico, an aluminum-nickel-cobalt alloy. Another example of a ferromagnetic material includes ferromagnetic ceramics, such as those made from iron oxide and another metal (e.g., nickel, zinc).

[0034] In some implementations, the ferromagnetic material may be iron powder. In some cases, the iron powder may be particles having a diameter of about 1-100 μm. In some cases, the iron powder may be immobilized in a coating material. In some cases, the coating may be uniform across at least a portion of the screen or may be disposed in a periodic (uniformly repeating) pattern, such that the actuator may be located anywhere behind the screen. In some implementations, the ferromagnetic material may be in the form of iron oxide.

[0035] Examples of such patterns are shown in Figures 2A-D. According to various embodiments, the ferromagnetic material may be coated onto at least a portion of the screen in different patterns, such as exemplary patterns 202, 204, 206, or 208. Exemplary pattern 202 shows the magnetic material applied across the entire screen, such as via a coating. Exemplary pattern 204 shows the magnetic material applied in a crisscross pattern with a gap between the diagonal lines. Despite the light nature of the powder, the screen need not be covered in its entirety. Similarly, exemplary patterns 206 and 208 show the coating applied in diagonal and vertical lines, respectively.

[0036] In some cases, the coating can be localized to predetermined locations where the actuators will be located. An example of such a pattern 210 is shown in FIG. 2E, where the coating can be applied to locations 212a, 212b, ..., 212n where the actuators will be located proximate to the screen. Such locations can be uniformly or non-uniformly located depending on the location of the actuators. In some cases, the coating is applied to one surface of the screen, which is opposite the projection surface of the screen.

[0037] An advantage of these configurations is that the deposition density of the ferromagnetic material can be spatially varied, thereby allowing the effective shape and force of the actuators to be controllably customized (e.g., using a desired number of actuators and a desired magnitude of force at a desired frequency) to maximize speckle reduction and reduce visibility of the displacement.

[0038] In some embodiments, the magnetic material may include a diamagnetic material. A diamagnetic material has a weak negative magnetic susceptibility to a magnetic field. It has a weak or no intrinsic magnetic alignment, but can be induced to have an opposing magnetic field. It does not retain its magnetic properties when the external field is removed. Examples of diamagnetic materials include copper, silver, gold, mercury, and bismuth. In some embodiments, the diamagnetic material is in powder form similar to the ferromagnetic materials discussed above (e.g., iron oxide, iron powder) and may be coated over at least a portion of the screen as shown in Figures 2A-E.

[0039] In some embodiments, ferromagnetic and diamagnetic materials may be used in conjunction with one another. For example, the magnetic particles may be a mixture of ferromagnetic and diamagnetic materials. As another example, a ferromagnetic material may be deposited in one area of ​​the screen and a diamagnetic material may be deposited in another area of ​​the screen.

[0040] Those skilled in the art will recognize that any of the exemplary materials described above or other suitable materials can be used as ferromagnetic, diamagnetic, or other materials having magnetic properties (e.g., ferrimagnetic, paramagnetic, or superparamagnetic (e.g., nanoparticle) materials) to achieve the desired vibration and displacement of the screen.

[0041] The magnetic coating may be applied to the projection screen prior to mounting the screen to other scaffolding. Thus, in some embodiments, the magnetic coating may be stretchable so that the projection screen may be stretched during mounting, e.g., to remove wrinkles (e.g., the magnetic coating may be sufficiently stretchable to allow the projection screen to be stretched during mounting). In some embodiments, the magnetic coating may be a relatively stiff substrate material or may be applied onto such a substrate, e.g., a thin slab (e.g., about 1 mm thick or less) or tape.

[0042] In some implementations, to achieve the above, magnetic particles (e.g., iron powder) may be suspended in a stretchable binder or adhesive and / or coated onto the stretchable projection screen to maintain the stretchability of the underlying screen material. In some cases, the stretchable binder may be made of vinyl or other plastic (e.g., polyethylene terephthalate (PET), thermoplastic). In some cases, particles, e.g., ferrite particles, may be embedded in a binder, e.g., alkyd. In other cases, other types of resins for the magnetic coating may be used. The thickness of this coating may vary depending on the design requirements. In some variations, the thickness of the coating may range from 10 to 20 μm. In some embodiments, the magnetic coating may be painted, varnished, rubbed, or sprayed (e.g., as droplets) onto the projection screen. In some embodiments, the magnetic coating may be disposed on a substrate (e.g., tape) that can be glued, fixed, or otherwise applied to the projection screen. As used herein, "extensible" can refer to a structure having an elastic modulus of less than 300 megapascals (MPa), less than 200 MPa, less than 100 MPa, or in the range of 30-100 MPa, or in the range of 30-300 MPa, by way of example.

[0043] In some embodiments, the magnetic material may be a rolled, solid ferromagnetic (or diamagnetic or other material having magnetic properties) sheet, for example a thin foil having a thickness of less than 0.1 mm, 0.2 mm, 0.3 mm, or 0.5 mm. Such a continuous material may also advantageously provide the magnetic properties to the screen with little or no visible pitting.

[0044] Because large projection screens tend to move with air currents and can change position or shape depending on other factors such as temperature changes, the gap between the screen and the magnetic actuator(s) takes this into account in various embodiments. In some embodiments, the magnetic field lines are made sufficiently uniform so that they can cover the entire distance the screen can move without significant changes in magnetic field strength.

[0045] 3 is a simplified diagram of an electromagnetic actuator 300 in a horseshoe configuration positioned relative to a field of magnetic particles, according to some embodiments. In some embodiments, the electromagnetic actuator 300 may include multiple (e.g., at least three) core portions 302, 304, 306 defined based on an angle between the core portions (e.g., the angle between core portions 302 and 304). In some embodiments, the electromagnetic actuator 300 may include a curved core portion without corners.

[0046] In some embodiments, at least some of the core portions may have coils wound therearound. For example, FIG. 3 shows coil 308 wound around core portion 304 and coil 310 wound around core portion 306. In some implementations, core portion 304 may extend to core portion 305, and core portion 306 may extend to core portion 307. In some cases, core portions 305 and 307 may be at a different angle than core portions 304 and 306. As discussed above, coils 308 and 310 may carry a current and generate a magnetic field, indicated by magnetic field lines 312, around electromagnetic actuator 300.

[0047] 3 further illustrates an exemplary configuration of ferromagnetic material disposed on the screen along the plane of the screen, simplified with four magnetic elements located at positions A1, B1, B2, A2. In some embodiments, each of the magnetic elements is a coating of ferromagnetic material (e.g., iron powder suspended in a binder), or a strip or tape or other type of substrate to which a coating is applied. In some embodiments, these magnetic elements may be arranged as vertical lines (e.g., exemplary pattern 208 of FIG. 2D where each line is a magnetic element) or at positions corresponding to actuator positioning (e.g., exemplary pattern 210 of FIG. 2E).

[0048] In some embodiments, there may be fewer or more than four magnetic elements (e.g., 2, 10, 64, 100, 600, or more). In some embodiments, the screen may have a magnetic coating applied and disposed uniformly across the screen or a portion thereof. In some embodiments, the magnetic elements are representations of areas of the screen that have a magnetic coating applied across at least a portion of the screen.

[0049] 3, the magnetic material in area 314 corresponding to locations A1 and A2 closest to the core (e.g., closest to core portions 305 and 307) may experience a greater electromotive force than the magnetic material in area 316 corresponding to locations B1 and B2 that are farther away from the core. Thus, this configuration can create a curved profile for actuation on the screen. In particular, the electromagnetic actuator 300 remains at a distance, e.g., a prescribed distance, that allows for magnetic interaction with the screen without physical contact with the screen.

[0050] In various implementations, the geometry of the actuators can be adjusted to generate different profiles. However, the density of the magnetic material (e.g., density of magnetic particles) can also be adjusted to control the spatial profile of actuation on the screen. For example, in some configurations, the magnetic material may only be present at positions A1 and A2 of the screen, since positions B1 and B2 are not as strongly affected by the magnetic field. In some other configurations, the density of particles at positions B1 and B2 may be greater than the density of particles at positions A1 and A2, such that the screen experiences a generally uniformly applied electromotive force.

[0051] A myriad of similar configurations of magnetic material and actuator(s) portions may be possible, as desired. For example, positions A1, B1, B2, A2 may be positioned horizontally or vertically (or diagonally at any angle in between). As another example, the ends of the "horseshoe" may be positioned azimuthally or in elevation (or at any orientation in between).

[0052] In some embodiments, a controller (not shown) can provide actuation signals to the electromagnetic actuator 300. The actuation signals can range from simple waveforms (sine, triangular, square, etc.) to complex or pseudo-random waveforms. In some cases, these control signals can be synchronous or asynchronous with other actuators that affect the screen.

[0053] In some embodiments, the controller may provide an actuation signal that causes a power source (not shown) to generate a current with defined parameters. In some implementations, the controller (e.g., via an actuation signal) may cause the power source to generate a current for a series of actuators that is timed to operate at one or more defined frequencies. For example, the actuators may operate at two frequencies, e.g., 32 Hz and 35 Hz. The two frequencies may be slightly offset between the rows of actuators to avoid standing waves. In some cases, the actuators may be configured such that adjacent units differ by 3-4 Hz, e.g., 32 Hz and 35 Hz, or 32 Hz and 36 Hz. In some implementations, the frequency may range from 30 Hz up to, e.g., 36 Hz. Thus, the screen may vibrate at different frequencies in different positions (e.g., one side vibrates at 32 Hz and the other side vibrates at 35 Hz). The frequency may be selected between 30-36 Hz based on the perceptibility of undesirable audibility or noise from the screen movement. However, in other implementations, the frequency may be outside the range of 30-36 Hz, for example a frequency in the range of 25-100 Hz may be used.

[0054] In some implementations, the actuation signal may send a current that generates a defined magnitude of vibration or displacement of the screen via the magnetic force generated by the actuator(s). This is based on the fact that the electromotive force generated by an electromagnetic actuator is proportional to the magnitude of the current provided to it. In some embodiments, the displacement may be sufficient to remove speckle from the observer's perception (e.g., 1 mm movement). However, excessive movement (e.g., more than 10 mm) may be perceptible and / or noisy and thus distracting to the observer. Furthermore, causing excessive movement may involve impractical levels of energy or power. In some implementations, the actuation signal may send a current that causes the screen to vibrate in a particular direction, e.g., from left to right, from top to bottom, diagonally, or vice versa, or a combination thereof. That is, the movement of the screen may be an oscillatory movement at a particular frequency (e.g., 30-36 Hz) and / or a particular displacement (e.g., 1 mm). In some implementations, the density of the magnetic material deposited on the screen may also affect the pattern of the screen's movement.

[0055] Thus, advantageously, vibrating or shaking the screen at a defined frequency and / or displacement can reduce speckle or other interference artifacts perceived by an observer of the screen.

[0056] FIG. 4 illustrates a configuration of a non-contact electromagnetic actuator 402 positioned stationary relative to a screen 404. In some embodiments, one or more cables 406 are held in tension. Each cable 406 may have an electromagnetic actuator 402 attached thereto. The cables 406 may be positioned away from the screen 404 such that the electromagnetic actuator 402 does not contact the screen. In some embodiments, the electromagnetic actuator 402 may be an example of the electromagnetic actuator 100 as shown in FIG. 1 or the electromagnetic actuator 300 as shown in FIG. 3. The screen 404 may be an example of the screen 116 of FIG. 1 or any of the screens 202-210 as shown in FIGS. 2A-E. According to various implementations, the screen 404 may have magnetic material applied or affixed to the screen in the form described above, such as a coating (e.g., ferrite particles embedded in a binder such as an alkyd), a strip or tape having such a coating, or a rolled sheet (e.g., a foil).

[0057] FIG. 5 shows a cross-sectional view of a projection screen apparatus 500 configured to vibrate in a direction perpendicular to the plane or surface of the screen, according to some embodiments. In some embodiments, the projection screen apparatus 500 can include (i) a screen 502 impregnated with, embedded with, or covered with a magnetic material (e.g., embedded in a binder or coated with a ferromagnetic material such as iron powder on a substrate, or a rolled metal sheet), and / or (ii) a layer 504 having one or more magnetic elements 505 (e.g., thin rubber permanent magnet strips). In some implementations, the layer 504 can be optional. In some implementations, the screen 502 can be captured and held by permanent magnets, which can be held stationary by cables, poles, stands, or other scaffolding such as a wall.

[0058] In some embodiments, the permanent magnet strips 505 of the layer 504 have a prescribed maximum energy product (BH max, in units of Megagauss-Oersted (MG-Oe) and / or a specified magnetic flux density associated therewith, e.g., 60 mT (in units of millitesla). In some embodiments, the permanent magnet strip 505 can have a relatively thin thickness, e.g., 0.5 mm. In some implementations, the layer 504 can be the same color as the screen 502, e.g., white, to allow for optical transparency.

[0059] The projection screen apparatus 500 may be configured to magnetically interact with the layer 506 having one or more current carrying circuit elements 506a. In some embodiments, the current carrying circuit elements 506a may be electromagnetic actuators. In some cases, the current carrying circuit elements 506a may be circular in shape (the illustrated example), but may also be square or rectangular in shape, or other shapes. In some cases, there may be a single or multiple current carrying circuit elements 506a in the layer 506. In some embodiments, the layer 506 (including the one or more current carrying circuit elements 506a) may be electromagnetic actuators. In some implementations, the current carrying circuit elements may include coils, traces, or other conductive wires embedded in a flexible circuit material. For example, the layer 506 is made of or includes flexible strips or layers that sandwich the current carrying circuit elements 506a. In some cases, there may be two or more flexible strips or layers. In some cases, the current carrying circuit elements 506a may be powered by a power source (not shown) through a wall, cable, or other scaffolding. The power source may be controlled by a controller (not shown). In some implementations, the layer 506 may be separate from the screen 502, fixed or otherwise held stationary (e.g., to a wall, cable, pole, stand, or other scaffolding) and substantially parallel to the screen 506, and the current carrying circuitry 506a may not be directly attached to the screen 502.

[0060] To that end, in some embodiments, there may be a gap 508 separating the layers 504 and 506. In some implementations, the gap 508 may include an air gap, a low hardness material (e.g., gel, rubber, plastic with a low hardness (durometer)), a dielectric material, or another damping medium between the layers 504, 506. Such a gap 508 prevents contact between the projection screen apparatus 500 and the layer 506 with the current carrying circuitry 506a, allowing only magnetic influences to cause movement of the screen 502.

[0061] In some embodiments, one or more current carrying circuit elements 506a may be disposed in a plane substantially parallel to the plane of the projection screen arrangement 500 (including, for example, the plane of the screen 502 or the layer of magnetic elements 504). The current carrying circuit elements 506a are shown in two ways: (i) in cross-sectional views 506a-i as part of the layer 506, with inbound current flow "x" (current entering perpendicular to the plane of the page) and outbound current flow "o" (current exiting perpendicular to the plane of the page); and (ii) in front views 506a-ii. That is, the inbound portion 506a-1 of the current carrying circuit element 506a from the front view may correspond to the inbound "x" of the cross-sectional view, and the outbound portion 506a-2 of the current carrying circuit element 506a from the front view may correspond to the outbound "o" of the cross-sectional view. Thus, the cross-sectional views 506a-i show the opposite direction of current flow.

[0062] In some embodiments, (i) axis 510 may be associated with inbound portion 506a-1, (ii) axis 512 may be associated with outbound portion 506a-2, and (iii) axis 514 may be associated with a magnetic element 505 (e.g., a permanent magnet strip with a defined magnetic polarity or orientation) disposed proximate to current carrying circuit element 506a (e.g., through the center of the magnetic element). Each of these axes 510, 512, 514 may be substantially parallel to one another.

[0063] In some embodiments, the axes 510, 512 associated with the inbound and outbound portions of the current carrying circuit 506a may be offset from the axis 514 associated with the magnetic element 505, meaning that the axes are parallel but do not have to overlap.

[0064] In some embodiments, the current in the current carrier circuit 506a may be controlled or varied to modulate the net force applied to the screen 502. In such embodiments, the flow of current through the current carrier circuit 506a may generate a magnetic field that causes the screen 502 to move orthogonally to the plane of the screen 502. Because the traces of the current carrier circuit 506a are offset from the screen 502 and the permanent magnet strips 505, the generated magnetic field may induce the screen 502 and / or the permanent magnet strips 505 to be repelled or attracted to the current carrier circuit 506a. In some embodiments, the permanent magnet strips 505 provide a permanent magnetic field B that interacts with the current applied to the coils of the current carrier circuit 506a. More directly, the configuration of the current carrier circuit 506a and the magnetic field generated by the permanent magnet strips 505 are adaptations of Ampere's law and Faraday's law. According to Ampere's circuit law, for any closed loop path, (i) the sum of the effective length segments of the conductors times (ii) the magnetic field in the direction of the length segments is equal to the product of the magnetic permeability and the current produced in the closed loop. When an oscillating magnetic field is produced by a current-carrying conductor placed under the magnetic field, an electromotive force is produced (in accordance with Faraday's law, referred to elsewhere herein) resulting in an oscillatory motion of the screen 502.

[0065] In some embodiments, the strength of the permanent magnet strip 505 and the number of turns of the coil of the current carrying circuit 506a may depend on the size of the screen 502 and its inertia. For example, the larger the screen, the greater the strength or number of permanent magnets used, the magnitude of the current, or the number of turns of the coil. In some embodiments, the presence of the magnetic element 505 may amplify the effect of the magnetic flux generated by the current carrying circuit element 506a, for example, by causing a stronger electromotive force to be applied to the screen 502, allowing for greater or more controlled magnetically induced motion. The current through the current carrying circuit 506a may alternate direction based on an actuation signal from a controller to cause a rocking or vibration in the orthogonal directions with a desired pattern, frequency, duration, and / or magnitude (displacement). The rocking or vibration resulting from these characteristics may thus reduce speckle or other interference artifacts perceived by an observer of the screen.

[0066] FIG. 6 illustrates a configuration of a screen 602 disposed relative to current carrying circuits useful for implementing a projection screen apparatus such as projection screen apparatus 500 or 700. In some embodiments, the screen 602 may be an example of the screen 502 of FIG. 5 and may have a magnetic material applied thereto (such as an iron powder coating, tape, etc. as described elsewhere herein). In some implementations, the screen 602 may include additional magnetic elements, such as permanent magnet strips 505. In some embodiments, these current carrying circuits may be an example of current carrying circuit elements 506a and may be embedded in the flexible circuit material (e.g., one or more strips 606). In some embodiments, there may be an air gap 608 between the screen 602 and the strips 606. However, in some embodiments, other damping media may be disposed at least partially between the screen 602 and the strips 606. In some embodiments, the strips 606 may be secured to one or more cables 604 which may be held stationary at position 610, e.g., via tension (or other attachment means, e.g., to the floor and ceiling, or to a wall or other support), such that the strips 606 are supported (or restrained) by the cables 604 and held stationary relative to the screen 602.

[0067] In some embodiments, the current carrying circuit elements embedded in the strips may be electrically connected to each other, to a power source (not shown), and / or to a controller (not shown). In some implementations, the connections may be made by connections, e.g., wires, that are threaded through or passed along the cable 604 or other scaffolding.

[0068] When a current (e.g., alternating at a prescribed frequency and duration) is driven through one or more of the strips 606 having current carrying circuit elements, the screen 602 can move relative to the strips, for example vibrating or oscillating orthogonally (e.g., according to the embodiment described with respect to FIG. 5) or laterally (e.g., according to the embodiment described with respect to FIG. 7 described below) relative to the strips.

[0069] 7 shows a cross-sectional view of a projection screen apparatus 700 configured to vibrate laterally relative to the plane or surface of the screen, according to some embodiments. In some embodiments, the projection screen apparatus 700 can include a screen 702 impregnated with, embedded with, or coated with a magnetic material (e.g., embedded in a binder or coated with a ferromagnetic material such as iron powder on a substrate, or a rolled metal sheet), and / or (ii) a layer 704 having one or more magnetic elements 705 (e.g., thin rubber permanent magnet strips). In some implementations, the screen 702 can be captured and held by permanent magnets, which can be held stationary by cables, poles, stands, or other scaffolding such as a wall.

[0070] In some embodiments, the permanent magnet strips 705 of the layer 704 have a prescribed maximum energy product (BH max , in Megagauss-Oersted (MG-Oe) and / or may have a specified magnetic flux density associated therewith (e.g., 60 mT). In some embodiments, the permanent magnet strip 505 may have a relatively thin thickness, e.g., 0.5 mm. In some implementations, the layer 704 may be the same color as the screen 702, e.g., white, to allow for optical transparency.

[0071] The projection screen apparatus 700 may be configured to magnetically interact with the layer 706 having one or more current carrying circuit elements 706a. In some embodiments, the current carrying circuit elements 706a may be electromagnetic actuators. In some embodiments, the layer 706 (including the one or more current carrying circuit elements 706a) may be electromagnetic actuators. In some implementations, the current carrying circuit elements may include flat coils, traces on a substrate, or other conductive wires embedded in a flexible circuit material. For example, the layer 706 is made of or includes flexible strips or layers that sandwich the current carrying circuit elements 706a. In some cases, there may be two or more flexible strips or layers. In some cases, the current carrying circuit elements 706a may be powered by a power source (not shown) via a wall, cable, or other scaffolding. The power source may be controlled by a controller (not shown). In some implementations, layer 706 may be fixed or otherwise held stationary (e.g., to a wall, cable, pole, stand, or other scaffolding) separate from and substantially parallel to screen 702, and current carrying circuitry 702a may not be directly attached to screen 702. To that end, in some embodiments, there may be a gap 708 separating layers 704 and 706. Gap 708 may be one example of gap 508 of FIG.

[0072] In some embodiments, one or more current carrying circuit elements 706a may be disposed in a plane substantially parallel to the plane of the projection screen arrangement 700 (e.g., including the plane of the screen 702 or the layer of magnetic elements 704). The current carrying circuit element 706a is shown in cross-sectional views 706a-i (with inward and outward directions of current flow) and in isometric views 706a-ii. Similar to cross-sectional views 506a-i of FIG. 5, opposite directions of current flow are shown by inbound portion 706a-1 and outbound portion 706-2. In some embodiments, at least some of the current carrying circuit elements 706a may include a trace pattern in which the current flow is alternated and spaced apart by, for example, 6 mm to 25 mm.

[0073] In some embodiments, (i) axis 710 may be associated with outbound portion 706a-2 and magnetic element 505a (e.g., a permanent magnet strip with a magnetic polarity or orientation), and (ii) axis 712 may be associated with outbound portion 706a-1 and magnetic element 505b (e.g., another permanent magnet strip with the same magnetic polarity or orientation). Axes 710, 712 may be substantially parallel to each other. That is, each of axes 710, 712 (associated with inbound and outbound portions of current carrier circuit 706a) may be aligned with its respective current carrier circuit 706a and magnetic element (e.g., permanent magnet strip 705a or 705b) to provide alignment of magnetic polarities. In other words, the current driven through current carrier circuit 706a may be "in phase" with one or more magnetic elements. When an alternating current is applied to the coil of current carrier circuit 706a, electromotive forces may cause the screen 702 to undergo an oscillatory displacement.

[0074] In some embodiments, the current in the current carrying circuit 706a may be controlled or varied to modulate the net force applied to the screen 702. In such embodiments, the flow of current through the current carrying circuit 706a may generate a magnetic field that causes the screen 702 to move laterally relative to the plane of the screen 702. Because the traces of the current carrying circuit 706a are aligned with the permanent magnet strips 705, the generated magnetic field may induce the screen 702 and / or the permanent magnet strips 705 to move laterally. The strength of the permanent magnet strips 705 and the number of turns of the coils of the current carrying circuit 706a may depend on the size of the screen 702 and its inertia. For example, the larger the screen, the greater the strength or number of permanent magnets used, the magnitude of the current, or the number of turns of the coils may be. In some embodiments, the presence of the magnetic element 705 may amplify the effect of the magnetic flux generated by the current carrying circuit element 706a, for example by causing a stronger electromotive force to be applied to the screen 702, allowing for greater or more controlled magnetically induced movement. The current through the current carrier circuit 706a may alternate direction based on an actuation signal from a controller to induce the lateral in-plane oscillation or vibration in a desired pattern, frequency, duration, and / or magnitude (displacement). The oscillation or vibration resulting from these characteristics may thus reduce the perception of speckle or other interference artifacts by a viewer of the screen.

[0075] method FIG. 8 is a flow diagram illustrating a method 800 for reducing speckle, according to some embodiments. One or more of the functions of the method 800 may be performed by a computerized device or system. Means for performing the functions illustrated in one or more of the steps illustrated in FIG. 8 may include hardware and / or software components of such a computerized device or system, such as, for example, a device, a computer system, a computer readable device, etc. The computer readable device includes a storage medium having stored thereon computer readable and / or computer executable instructions configured to cause at least one processor device or another device to perform an operation when executed by a processor device. Exemplary components of a computerized device or system are illustrated in FIG. 10 and described in more detail below. A controller may be an example of a computerized device or system.

[0076] It should also be noted that the operations of method 800 may be performed in any suitable order, not necessarily in the order shown in Figure 8. Additionally, method 800 may include additional or fewer operations than those shown in Figure 8 to perform speckle reduction.

[0077] In some embodiments, the speckle comprises a plurality of interference artifacts on the projection screen, hi some embodiments, the projection screen may comprise magnetic particles disposed on at least a portion of the projection screen.

[0078] In step 802, the method 800 may include generating and transmitting one or more signals to an electromagnetic actuator. In some embodiments, the electromagnetic actuator may be positioned at a distance from magnetic particles disposed on the projection screen. In some implementations, the magnetic particles disposed on the projection screen may include ferromagnetic particles or diamagnetic particles, or the magnetic particles may be a combination of ferromagnetic and diamagnetic particles, or other types of materials with magnetic properties (e.g., ferrimagnetic, paramagnetic, or superparamagnetic (e.g., nanoparticle) materials). In some implementations, the magnetic particles may include iron powder. In some implementations, the iron powder may be suspended in a binder. In some cases, the binder may include a resin, e.g., an alkyd, and may be coated on the projection screen.

[0079] The coating or application / spraying of magnetic particles can be in various patterns, such as those shown in Figures 2A-E. In some variations, the pattern can be a non-uniform pattern of deposition of the magnetic particles at a first density in a first portion of the projection screen and at a second density in a second portion of the projection screen, the second density being different from the first density. For example, locations 212a and 212n as shown in Figure 2E can have ferromagnetic particles deposited at different densities or concentrations (e.g., per area or per volume). In some variations, the pattern can be a uniform pattern, where the magnetic particles are deposited substantially uniformly across at least a portion of the projection screen. In some variations, the magnetic particles are deposited across the entire projection screen, or at least across the entire active image area of ​​the projection screen, the active image area including the area configured for use as a projection screen, but excluding any peripheral support areas that provide some other function (such as physically supporting the active image area).

[0080] In some embodiments, the electromagnetic actuator may include a core and one or more coils disposed about at least a portion of the core. In some implementations, the core may have a bar configuration (as shown in FIG. 1) or a horseshoe configuration (as shown in FIG. 3). Various other shapes and configurations may be possible.

[0081] In some embodiments, the electromagnetic actuator may be a planar element, such as a current carrying circuit having a trace or wire coiled in a flexible strip or layer. Examples of current carrying circuits are shown in FIG. 5 and FIG. 7. In some implementations, the screen may include one or more magnetic elements (e.g., permanent magnet strips), and the current carrying circuit may be disposed substantially parallel to the screen. Each of the one or more current carrying circuits may include at least a first trace portion carrying a current in a first direction and at least a second trace portion carrying a current in an opposite second direction. In some variations, the first and second trace portions may be aligned in an offset configuration with respect to the one or more magnetic elements. In some variations, the first and second trace portions may be aligned with the one or more magnetic elements.

[0082] 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 source configured to drive a current through the electromagnetic actuator, e.g., through a coil thereof. In some cases, the power source may be external to the electromagnetic actuator, or may be internal to and 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, processor, and / or memory electrically coupled to the core and / or coil to receive and act on signals from at least the controller.

[0083] At step 804, method 800 may include causing the electromagnetic actuator to generate a magnetic field based on the transmitted one or more signals. In some embodiments, the controller may transmit a signal (e.g., via a power source) configured to cause a current to flow through a coil or trace associated with the electromagnetic actuator, thereby generating a magnetic field that can repel or attract other magnetic elements depending on the direction of the current. For example, a projection screen may be positioned a distance from the electromagnetic actuator.

[0084] In step 806, the method 800 may include inducing a motion of the projection screen via an interaction of the generated magnetic field with the magnetic particles across the distance. The motion at least partially mitigates visual perceptibility of speckle. The motion of the projection screen may be a vibration motion at a specific frequency (e.g., 30-36 Hz) and / or a specific displacement (e.g., 1 mm). In some embodiments, the motion of the projection screen may include multiple frequencies. For example, the motion may include a motion at a first frequency at a first position of the projection screen and a motion at a second frequency at a second position of the projection screen, the first and second frequencies including different frequencies selected from a range.

[0085] In some embodiments, the motion of the projection screen may include motion in a direction perpendicular to the projection screen, hi some embodiments, the motion of the projection screen may include motion lateral to the projection screen.

[0086] 9 is a flow diagram illustrating a method 900 for obtaining a projection screen configured to enable speckle reduction, according to some embodiments. One or more of the functions of method 900 may be performed by a computerized device or system.

[0087] Method 900 may include additional or fewer operations than those illustrated in FIG. 9 to perform acquisition of a projection screen configured to enable speckle reduction.

[0088] At step 902, method 900 may include applying a magnetic material (e.g., a ferromagnetic material and / or a diamagnetic material) to at least a portion of the projection screen. In some embodiments, the ferromagnetic material may be applied to enable a magnetic field from a non-contact magnetic driver to impart a force to the screen, resulting in vibration of the projection screen (step 904), to at least partially mitigate the visual perceptibility of speckle.

[0089] In some implementations, the force can be an electromotive force that affects an object (having magnetic properties, e.g., having a magnetic material disposed on the object) from a distance. In some cases, applying the ferromagnetic material can include coating at least a portion of the projection screen with a suspension including ferromagnetic particles. In some variations, the ferromagnetic particles can include or be based on alloys including iron, nickel, cobalt, or combinations thereof. In some variations, other types of ferromagnetic particles can be used, e.g., ferromagnetic ceramics such as those made from gadolinium, neodymium, and / or alnico, or iron oxide and another metal (e.g., nickel, zinc).

[0090] In some embodiments, applying the ferromagnetic material may include securing one or more sheets of ferromagnetic material in a rolled form. Variations in the sheets may be implemented, such as sheets having thicknesses of less than 0.1 mm, 0.2 mm, 0.3 mm, or 0.5 mm.

[0091] In some embodiments, applying the ferromagnetic material may be non-uniform or substantially uniform across at least a portion of the projection screen. In some implementations, the ferromagnetic particles may be spatially arranged at a first density in a first portion of the projection screen and at a second density in a second portion of the projection screen, the second density being different from the first density.

[0092] Device FIG. 10 is a block diagram illustrating an example of components of an apparatus capable of implementing various aspects of the disclosure. As with other figures provided herein, the types and numbers of elements shown in FIG. 10 are provided merely as examples. Other implementations may include more, fewer, and / or different types and numbers of elements. According to some examples, the apparatus 1000 may be configured to perform at least some of the methods disclosed herein. In some implementations, the apparatus 1000 may be or include a device configured to control an electromagnetic actuator for causing a movement of the projection screen. In some implementations, the apparatus 1000 may be or include a device that includes an electromagnetic actuator for causing a movement of the projection screen. In some implementations, the apparatus 1000 may be or include a device configured to apply or cause the application of a magnetic material to at least a portion of the projection screen.

[0093] In this example, the device 1000 includes an interface system 1005 and a control system 1010. The interface system 1005, in some implementations, may be configured to communicate with one or more other devices. The interface system 1005, in some implementations, may be configured to exchange control information and associated data. The control information and associated data, in some examples, may relate to one or more software applications that the device 1000 is executing.

[0094] The interface system 1005 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 1005 may include one or more wireless interfaces. In some examples, the interface system 1005 may include one or more interfaces between the control system 1010 and a memory system, such as the optional memory system 1015 shown in FIG. 10 . However, the control system 1010 may include a memory system in some examples. The interface system 1005 may be configured in some implementations to receive signal inputs or provide signals, for example, to an electromagnetic actuator (e.g., 100, 300, 402, 506, 506a, 706, 706a) or a power source.

[0095] The control system 1010 may include, for example, a general purpose single-chip or multi-chip 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 device may be an example of the control system 1010 or a portion of the control system 1010.

[0096] In some implementations, the control system 1010 may reside in more than one device. For example, in some implementations, a portion of the control system 1010 may reside in a device within one of the environments illustrated herein, and another portion of the control system 1010 may reside in a device outside of 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 1010 may reside in a device within one environment, and another portion of the control system 1010 may reside in one or more other devices of the environment. For example, a portion of the control system 1010 may reside in a device implementing a cloud-based service, such as a server, and another portion of the control system 1010 may reside in another device implementing a cloud-based service, such as another server, a memory device, etc. The interface system 1005 may also reside in more than one device, in some examples.

[0097] In some implementations, the control system 1010 may be configured to at least partially perform the methods disclosed herein. According to some examples, the control system 1010 may be configured to cause an electromagnetic actuator to generate an electromotive force, such as by sending or receiving a control signal. According to some examples, the control system 1010 may be configured to apply or cause the application of a magnetic material (e.g., ferromagnetic powder) to at least a portion of a projection screen to obtain a projection screen constructed such that it can be used with the embodiments and implementations described herein. According to other examples, the control system 1010 may be configured to obtain the applicable magnetic material, such as by mixing the magnetic material with a resin.

[0098] Some or all of the methods described herein may be performed by one or more devices according to instructions (e.g., software) stored in 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, and the like. The one or more non-transitory media may be present, for example, in optional memory system 1015 and / or control system 1010 shown in FIG. 10. Thus, various inventive aspects of the subject matter described in this disclosure may be implemented in one or more non-transitory media having software stored thereon. The software may include, for example, instructions for determining gain parameters, applying a gain transition function, determining an inverse gain transition function, applying the inverse gain transition function, allocation bits for gain control on a bitstream, and the like. The software may be executable by one or more components of a control system, such as, for example, control system 1010 of FIG. 10.

[0099] Some aspects of the disclosure include systems or devices, e.g., programmed, configured to perform one or more examples of the disclosed methods, and tangible computer-readable media, e.g., disks, that store code for implementing one or more examples of the disclosed methods or steps thereof. For example, some disclosed systems may 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 embodiments of the disclosed methods or steps thereof. Such a general-purpose processor may be or include a computer system that includes 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 asserted data.

[0100] Some embodiments may be implemented as a configurable (e.g., programmable) digital signal processor (DSP) configured (e.g., programmed and otherwise configured) to perform the necessary processing on the audio signal(s), including performing one or more examples of the disclosed methods. Alternatively, embodiments of the disclosed system (or elements thereof) may be implemented as a general-purpose processor, such as a personal computer (PC) or other computer system or microprocessor, which may include input devices and memory, and which is programmed and / or otherwise configured with software or firmware 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, the system also including other elements. The other elements may include one or more loudspeakers and / or one or more microphones. The 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, for example, a mouse and / or a keyboard. The general-purpose processor may be coupled to a memory, a display device, etc.

[0101] Another aspect of the disclosure is a computer-readable medium, such as a disk or other tangible storage medium, that stores code for performing one or more examples of the disclosed methods or steps thereof, e.g., by a coder executable to perform the same.

[0102] While particular embodiments of and applications of the present disclosure have been described herein, it will be apparent to those skilled in the art that many variations on the embodiments and applications described herein are possible without departing from the scope of the present disclosure as described and claimed herein. Although certain forms of the present disclosure have been illustrated and described, it will be understood that the present disclosure should not be limited to the specific embodiments described and illustrated, or to the specific manner described.

[0103] Various aspects of the present invention can be understood from the following enumerated example embodiments (EEE).

[0104] [EEE1] 1. A method for reducing speckle, the speckle comprising a plurality of interference artifacts on a projection screen, the projection screen comprising a magnetic material disposed on at least a portion of the projection screen, the method comprising: generating and transmitting one or more signals to an electromagnetic actuator, the electromagnetic actuator positioned at a distance from the magnetic material, the magnetic material comprising magnetic particles, the magnetic particles secured in an extensible binder, and disposed on the projection screen, the electromagnetic actuator generating a magnetic field in response to the transmitted one or more signals, the generated magnetic field interacting with the magnetic material to move the projection screen to at least partially reduce visual perceptibility of the speckle.

[0105] [EEE2] The method of EEE1, wherein the magnetic particles disposed on the projection screen include ferromagnetic particles or diamagnetic particles, or a combination thereof, deposited in a pattern that is at least partially defined on one side of the projection screen.

[0106] [EEE3] The method of EEE1 or 2, wherein the defined pattern includes a non-uniform pattern of deposition at a first non-zero density in a first portion of the projection screen and a second non-zero density in a second portion of the projection screen, the second density being different from the first density.

[0107] [EEE4] A method according to any one of EEE1 to 3, wherein the magnetic particles comprise iron powder suspended in the extensible binder, the extensible binder comprises a resin and is coated onto the projection screen.

[0108] [EEE5] The method of any one of EEE1 to EEE4, wherein the resin comprises an alkyd.

[0109] [EEE6] The method of any one of EEE1 to EEE5, wherein the movement of the projection screen includes movement in a direction perpendicular to the projection screen.

[0110] [EEE7] ​​A method according to any one of EEE1 to 6, wherein the electromagnetic actuator comprises a substantially planar element substantially parallel to the projection screen, the substantially planar element comprising one or more current carrying circuits aligned in a defined configuration relative to the magnetic material.

[0111] [EEE8] A method according to any one of EEE1 to 7, wherein the movement of the projection screen includes lateral movement relative to the projection screen.

[0112] [EEE9] A method according to any one of EEE1 to 8, wherein the electromagnetic actuator comprises a substantially planar element substantially parallel to the projection screen, the substantially planar element comprising one or more current carrying traces aligned in a defined configuration relative to the magnetic material.

[0113] [EEE10] The method of any one of EEE1 to EEE9, wherein the electromagnetic actuator has a ferromagnetic core and one or more coils disposed about at least a portion of the ferromagnetic core.

[0114] [EEE11] A method according to any one of EEE1 to 10, wherein generating and transmitting one or more signals to the electromagnetic actuator comprises generating and transmitting one or more signals that vibrate the projection screen at one or more defined frequencies, each defined frequency being between 30 Hz and 36 Hz (inclusive).

[0115] [EEE12] The method of any one of EEE1 to 11, wherein the movement of the projection screen includes movement at a first position of the projection screen at a first frequency and movement at a second position of the projection screen at a second frequency, the first and second frequencies including different frequencies selected from the range of 30 Hz to 36 Hz (inclusive).

[0116] [EEE13] The method of any one of EEE1 to 12, further comprising positioning the projection screen at a distance from an electromagnetic element configured to generate a magnetic field.

[0117] [EEE14] The method of any one of EEE1 to 13, wherein the extensible binder has an elastic modulus of 30 to 100 megapascals.

[0118] [EEE15] The method of any one of EEE1 to EEE14, wherein the extensible binder is sufficiently extensible to allow the projection screen to be stretched during installation.

[0119] [EEE16] A method for obtaining a projection screen that can be vibrated by a non-contact magnetic driver to at least partially reduce the visual perceptibility of speckle, the method comprising: applying a magnetic material to at least a portion of the projection screen, the applying of the magnetic material comprising at least one of: coating the at least a portion of the projection screen with an extensible binder having magnetic particles fixed to the binder; fixing one or more sheets of the magnetic material in a roll having a thickness of less than 0.1 mm; depositing magnetic particles substantially uniformly across the projection screen; or spatially distributing magnetic particles at a first non-zero density on a first portion of the projection screen and at a second non-zero density on a second portion of the projection screen, the second density being different from the first density.

[0120] [EEE17] The method of EEE16, wherein the magnetic material comprises a ferromagnetic material.

[0121] [EEE18] The method of any one of EEE16 to 17, wherein the magnetic particles comprise an alloy containing iron, nickel, cobalt, or a combination thereof.

[0122] [EEE19] A method according to any one of EEE16 to 18, wherein applying the magnetic material comprises applying the one or more sheets of the magnetic material in a roll having a thickness of less than 0.1 mm.

[0123] [EEE20] The method of any one of EEE16 to 19, wherein the projection screen includes an active image area, and applying the magnetic material to at least a portion of the projection screen includes depositing the magnetic particles substantially uniformly across the active image area of ​​the projection screen.

[0124] [EEE21] A method according to any one of EEE16 to 20, wherein applying the magnetic material to at least a portion of the projection screen comprises spatially positioning the magnetic particles at the first non-zero density in the first portion of the projection screen and at the second non-zero density in the second portion of the projection screen.

[0125] [EEE22] A system for vibrating a projection screen, comprising: a projection screen including a magnetic material fixed in an extensible binder; at least one electromagnetic actuator positioned at a distance from the screen and configured to vibrate the projection screen via a magnetic field; and a controller configured in signal communication with the at least one electromagnetic actuator, the controller configured to generate and send one or more signals to the at least one electromagnetic actuator to cause the at least one electromagnetic actuator to generate the magnetic field, the generated magnetic field interacting with the magnetic material to vibrate the projection screen.

[0126] [EEE23] The system described in EEE22, wherein the magnetic material includes ferromagnetic particles arranged in a non-uniform or periodic pattern on one side of the projection screen, the non-uniform or periodic pattern including a first density of the ferromagnetic particles in a first portion of the projection screen and a second density of the ferromagnetic particles in a second portion of the projection screen.

[0127] [EEE24] The system described in EEE22 or 23, wherein the at least one electromagnetic actuator includes a ferromagnetic core and one or more coils disposed around at least a portion of the ferromagnetic core.

[0128] [EEE25] The system of any one of EEE22 to 24, wherein the projection screen further comprises one or more magnetic elements, the at least one electromagnetic actuator having a substantially planar element substantially parallel to the projection screen, the at least one electromagnetic actuator having one or more current carrying circuits, each of the one or more current carrying circuits having a first trace carrying current in a first direction and a second trace carrying current in an opposite second direction, the first and second traces being aligned in an offset configuration relative to the one or more magnetic elements, and the vibration of the projection screen comprises movement in an orthogonal direction relative to the projection screen.

[0129] [EEE26] The system of any one of EEE22 to 25, wherein the projection screen further comprises one or more magnetic elements, the at least one electromagnetic actuator comprises a substantially planar element substantially parallel to the projection screen, the actuator comprises one or more current carrying traces, each of the one or more current carrying traces having a first portion carrying current in a first direction and a second portion carrying current in an opposite second direction, the first and second portions being aligned with the one or more magnetic elements, and the vibration of the projection screen comprises a lateral movement relative to the projection screen.

[0130] [EEE27] A system described in any one of EEE22 to 26, wherein the controller is configured to generate and send one or more signals to the at least one actuator that vibrates the projection screen at a frequency of 30 to 36 Hz without contact between the projection screen and the at least one actuator.

[0131] [EEE28] The system of any one of EEE22 to 27, wherein the controller is further configured to generate and send to the at least one actuator one or more signals that cause the projection screen to vibrate at a first frequency of 30 Hz to 36 Hz in a first position and at a second frequency of 30 Hz to 36 Hz in a second position, the second frequency being different from the first frequency.

[0132] [EEE29] A projection screen comprising magnetic particles arranged on the projection screen in a spatial pattern, the magnetic particles being suspended in an extensible binder and either affixed to at least a portion of the projection screen or coated on at least a portion of the projection screen.

[0133] [EEE30] The projection screen according to EEE29, wherein the magnetic particles comprise iron powder and the expandable binder comprises an alkyd.

[0134] [EEE31] A projection screen described in EEE29 or 30, wherein the spatial pattern comprises a non-uniform pattern of the magnetic particles, the non-uniform pattern comprising a first density of the magnetic particles in at least a first region of the projection screen and a second density of the magnetic particles in at least a second region of the projection screen.

[0135] [EEE32] A projection screen according to any one of EEE29 to 31, wherein the spatial pattern comprises a uniform pattern of the magnetic particles across at least a portion of the projection screen.

[0136] [EEE33] The projection screen of any one of EEE29 to 32, wherein the extensible binder has an elastic modulus of 30 to 100 Megapascals.

[0137] [EEE34] A projection screen as described in any one of EEE29 to 33, wherein the extensible binder is sufficiently extensible to allow the projection screen to be stretched during installation.

Claims

1. 1. A system for vibrating a projection screen, the system comprising: A projection screen including a magnetic material fixed in an extensible binder; at least one electromagnetic actuator positioned at a distance from the screen and configured to vibrate the projection screen via a magnetic field; and a controller configured in signal communication with the at least one electromagnetic actuator, the controller comprising: configured to generate and transmit one or more signals to the at least one electromagnetic actuator to cause the at least one electromagnetic actuator to generate the magnetic field, the generated magnetic field interacting with the magnetic material to vibrate the projection screen. system.

2. 2. The system of claim 1, wherein the magnetic material comprises ferromagnetic particles arranged in a non-uniform or periodic pattern on one side of the projection screen, the non-uniform or periodic pattern comprising a first density of the ferromagnetic particles in a first portion of the projection screen and a second density of the ferromagnetic particles in a second portion of the projection screen.

3. The system of claim 1 or 2, wherein the at least one electromagnetic actuator includes a ferromagnetic core and one or more coils disposed around at least a portion of the ferromagnetic core.

4. the projection screen further comprises one or more magnetic elements; the at least one electromagnetic actuator having a substantially planar element substantially parallel to the projection screen, the at least one electromagnetic actuator having one or more current carrying circuits, each of the one or more current carrying circuits having a first trace carrying current in a first direction and a second trace carrying current in an opposite second direction, the first and second traces being aligned in an offset configuration with respect to the one or more magnetic elements; the vibration of the projection screen includes motion in an orthogonal direction relative to the projection screen; The system of claim 1 .

5. the projection screen further comprises one or more magnetic elements; the at least one electromagnetic actuator has a substantially planar element substantially parallel to the projection screen, the actuator having one or more current carrying traces, each of the one or more current carrying traces having a first portion carrying current in a first direction and a second portion carrying current in an opposite second direction, the first and second portions being aligned with the one or more magnetic elements; The system of claim 1 , wherein the vibration of the projection screen comprises lateral movement relative to the projection screen.

6. The system of claim 1 , wherein the magnetic material comprises iron powder suspended in the expandable binder, the expandable binder comprising a resin and coated onto the projection screen.

7. The system of claim 1 , wherein the resin comprises an alkyd.

8. 2. The system of claim 1, wherein generating and transmitting one or more signals to the electromagnetic actuator comprises generating and transmitting one or more signals that vibrate the projection screen at one or more defined frequencies, each defined frequency being between 30 Hz and 36 Hz inclusive.

9. 2. The system of claim 1, wherein the movement of the projection screen comprises movement of the projection screen at a first position at a first frequency and movement of the projection screen at a second position at a second frequency, the first and second frequencies comprising different frequencies selected from a range of 30 Hz to 36 Hz inclusive.

10. The system of claim 1 , wherein the extensible binder has a modulus of elasticity of 30 to 100 megapascals.

11. The system of claim 1 , wherein the extensible binder is sufficiently extensible to allow the projection screen to be stretched during installation.

12. The system of claim 1 , wherein the magnetic material comprises ferromagnetic or diamagnetic particles, or a combination thereof, deposited in a defined pattern at least partially on one side of the projection screen.

13. 1. A method for reducing speckle, the speckle comprising a plurality of interference artifacts on a projection screen, the projection screen comprising a magnetic material disposed on at least a portion of the projection screen, the method comprising: generating and transmitting one or more signals to an electromagnetic actuator; the electromagnetic actuator is positioned at a distance from the magnetic material, the magnetic material including magnetic particles; the magnetic particles are immobilized in an extensible binder and disposed on the projection screen; the electromagnetic actuator generating a magnetic field in response to the transmitted one or more signals; the generated magnetic field interacts with the magnetic material to move the projection screen to at least partially mitigate the visual perceptibility of the speckle. method.

14. 14. The method of claim 13, wherein the magnetic particles disposed on the projection screen comprise ferromagnetic particles or diamagnetic particles or a combination thereof deposited in a pattern defined at least partially on one side of the projection screen.

15. 15. The method of claim 14, wherein the defined pattern comprises a non-uniform pattern of deposition at a first non-zero density on a first portion of the projection screen and at a second non-zero density on a second portion of the projection screen, the second density being different from the first density.

16. The method of claim 13 , wherein the magnetic particles include iron powder suspended in the expandable binder, the expandable binder including a resin, and is coated onto the projection screen.

17. 17. The method of claim 16, wherein the iron powder has a diameter of 1 to 100 μm.

18. The method of claim 16 , wherein the resin comprises an alkyd.

19. The method of claim 13 , wherein the movement of the projection screen comprises movement in a direction perpendicular to the projection screen or movement lateral to the projection screen.

20. 14. The method of claim 13, wherein the electromagnetic actuator comprises a substantially planar element substantially parallel to the projection screen, the substantially planar element including one or more current carrying circuits aligned in a defined configuration relative to the magnetic material.

21. The method of claim 13 , wherein the electromagnetic actuator comprises a ferromagnetic core and one or more coils disposed about at least a portion of the ferromagnetic core.

22. 14. The method of claim 13, wherein generating and transmitting one or more signals to the electromagnetic actuator comprises generating and transmitting one or more signals that vibrate the projection screen at one or more defined frequencies, each defined frequency being between 30 Hz and 36 Hz inclusive.

23. 14. The method of claim 13, wherein the movement of the projection screen comprises movement of the projection screen at a first position with a first frequency and movement of the projection screen at a second position with a second frequency, the first and second frequencies comprising different frequencies selected from the range of 30 Hz to 36 Hz inclusive.

24. The method of claim 13 , further comprising positioning the projection screen a distance from an electromagnetic element configured to generate a magnetic field.

25. The method of claim 13, wherein the extensible binder has a modulus of elasticity of 30 to 100 megapascals.

26. 14. The method of claim 13, wherein the extensible binder is sufficiently extensible to allow the projection screen to be stretched during installation.

27. 1. A method for obtaining a projection screen that can be vibrated by a non-contact magnetic driver to at least partially reduce the visual perceptibility of speckle, the method comprising: applying a magnetic material to at least a portion of the projection screen, the applying of the magnetic material comprising at least one of: coating the at least a portion of the projection screen with an expandable binder having magnetic particles secured thereto; securing one or more sheets of the magnetic material in a roll having a thickness of less than 0.1 mm; depositing magnetic particles substantially uniformly across the projection screen; or spatially distributing magnetic particles at a first non-zero density on a first portion of the projection screen and at a second non-zero density on a second portion of the projection screen, the second density being different from the first density. method.

28. The method of claim 27 , wherein the magnetic material comprises a ferromagnetic material.

29. 29. The method of claim 27 or 28, wherein the magnetic particles comprise an alloy comprising iron, nickel, cobalt, or a combination thereof.

30. 28. The method of claim 27, wherein applying the magnetic material comprises applying the one or more sheets of the magnetic material in a roll having a thickness of less than 0.1 mm.

31. 30. The method of claim 27, wherein the projection screen includes an active image area, and applying the magnetic material to the at least a portion of the projection screen includes depositing the magnetic particles substantially uniformly across the active image area of ​​the projection screen.

32. 28. The method of claim 27, wherein applying the magnetic material to at least a portion of the projection screen comprises spatially positioning the magnetic particles at the first non-zero density in the first portion of the projection screen and at the second non-zero density in the second portion of the projection screen.

33. 1. A projection screen comprising magnetic particles arranged on the projection screen in a spatial pattern, the magnetic particles being suspended in an extensible binder and affixed to at least a portion of the projection screen or coated on at least a portion of the projection screen.

34. 34. The projection screen of claim 33, wherein the magnetic particles include iron powder and the expandable binder includes an alkyd.

35. 35. The projection screen of claim 33 or 34, wherein the spatial pattern comprises a non-uniform pattern of the magnetic particles, the non-uniform pattern comprising a first density of the magnetic particles in at least a first region of the projection screen and a second density of the magnetic particles in at least a second region of the projection screen.

36. 34. The projection screen of claim 33, wherein the spatial pattern comprises a non-uniform pattern of the magnetic particles, the non-uniform pattern comprising a first density of the magnetic particles in at least a first region of the projection screen and a second density of the magnetic particles in at least a second region of the projection screen.

37. 34. The projection screen of claim 33, wherein the spatial pattern comprises a uniform pattern of the magnetic particles across at least a portion of the projection screen.

38. 34. The projection screen of claim 33, wherein the extensible binder has a modulus of elasticity between 30 and 100 megapascals.

39. 34. The projection screen of claim 33, wherein the extensible binder is sufficiently extensible to allow the projection screen to be stretched during installation.

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