Virtual Screen

Abstract

A method and system (including a computer program product) for creating a virtual screen (208) for displaying a visible image in air is provided. A virtual screen generator (206) is provided. The virtual screen generator (206) comprises one or more light sources (302), a scanning means (304) for scanning light from the light sources (302) over a predefined space in air, and a control means for controlling the operation of the light sources (302) and the scanning means (304). The virtual screen generator (206) receives image data to be displayed on the virtual screen (208) and, using the control means, directs light from the one or more light sources (302) such that a collection of emitting points in the visible range of the electromagnetic spectrum is generated in the predefined space in air, which together form an image corresponding to the received image data.

Description

[Technical field]

[0001] The present invention relates to the formation of visible images, and more particularly to the formation of visible images in gaseous or liquid media such as air or water. [Background technology]

[0002] Mobile devices such as mobile phones and tablet computers are becoming more prevalent in society. They are used for a variety of purposes, including taking photos, listening to music and podcasts, searching the Internet for information, and viewing images and videos. Manufacturers of these devices must balance the benefits of portability (i.e., the size of the device) against the ease of use of the device. This is especially true when it comes to the screen size of the device, since it is one of the main factors that affect the overall size of a device in general.

[0003] In many devices, the user interacts with the device through a touch-sensitive screen, which is also used to display information to the user. Because the screen size is limited by the overall size of the device, it can be difficult for a user to, for example, read information on a web page or see an image displayed on the screen of a small device such as a mobile phone. Most devices allow the user to enlarge the content displayed on the screen, but in this case, usually only a small portion of the text or image is displayed on the screen, and the user must scroll or move the image or text on the screen, and cannot see the entire web page or image at any time.

[0004] Additionally, users often want to share the contents of their screen with other users. Even if it is possible to fully display a web page or image on the display screen of a device, it is difficult for multiple people to gather around the device and have an unobstructed view of the screen at the same time. In order for everyone to be able to clearly see the display, the device must often be placed at a distance from the user, which often makes it impossible to clearly see the content on the display from a distance. Thus, there is a need for new and improved ways to display content in a larger format than is possible on portable devices, and in a manner that is more accessible to the user of the device as well as to those with whom the content may be shared. [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 illustrates a method for defining a virtual screen according to one implementation. [Diagram 2] FIG. 2 illustrates an exemplary architecture of a system for displaying content on a virtual screen according to one implementation. [Diagram 3] FIG. 3 illustrates a virtual screen generator according to one implementation. [Figure 4] FIG. 4 illustrates a virtual screen generator according to one implementation. [Diagram 5] FIG. 5 illustrates a virtual screen generator according to one implementation.

[0006] Like reference numbers in the various drawings indicate like elements. Summary of the Invention

[0007] In some embodiments, the technology described herein relates to a method of creating a virtual screen for displaying a visible image in air, comprising providing a virtual screen generator including one or more light sources, a scanning means for scanning light from the light sources over a predefined space in the air, and a control means for controlling operation of the light sources and the scanning means; receiving, by the virtual screen generator, image data to be displayed on the virtual screen; and using the control means to direct the light from the one or more light sources such that a collection of emitting points within the visible range of the electromagnetic spectrum is created within the predefined space in the air, the collection of points collectively forming an image corresponding to the received image data.

[0008] Various embodiments may include one or more of the following features: The displayed image data may be an enlarged version of an image displayed on a user electronic device, such as a laptop, a mobile phone, a tablet computer, etc. The virtual screen generator may be connected to the user electronic device by a wired or wireless network.

[0009] The one or more light sources may be lasers. The scanning means may include one or more moveable mirrors configured to move light from the light source in a raster-like pattern across a predefined space in air while switching the light source on and off to produce short pulses of light.

[0010] The virtual screen generator may comprise two or more light sources and a scanning means for each light source, where each light source and scanning means may be configured to cover a particular portion of a predefined space. The scanning means may comprise one or more diffractive optical elements or spatial light modulators, and the control means may be configured to control operation of the light sources and spatial light modulators to generate a two-dimensional pattern of light emitting points in the predefined space in air.

[0011] The predefined space in air can be defined by adjusting the focal position of one or more light sources to create an essentially vertical plane in air forming the virtual screen. The one or more light sources can operate at a frequency outside the visible range, and the light emitting points are generated by plasma discharge in the predefined space in air. The virtual screen generator can comprise a substance emission means configured to fill the predefined space with a non-toxic gaseous medium, in which the light emitting points are generated by fluorescence induced by light from the one or more light sources. The gaseous medium and the one or more light sources can be selected such that the fluorescence occurs at different wavelengths, generating a virtual screen with multiple colors.

[0012] The virtual screen generator may comprise a substance emitting means configured to fill a predefined space with a non-toxic gas-liquid mixture to provide a reflective virtual screen onto which different colored lights from one or more light sources can be projected and reflected to a viewer. The virtual screen generator may comprise a containment means configured to generate an electric, magnetic, or ultrasonic field to essentially confine the substance emitted by the substance emitting means to the predefined space in air while displaying the image. The virtual screen generator may comprise a particle emitter configured to emit small reflective particles into the predefined space in air, and the control means may control the movement of the small particles using the electric, magnetic, or ultrasonic field such that the particles can move around within the predefined space in air while being illuminated and reflecting light from one or more light sources towards the viewer. The method may include calibrating the virtual screen based on ambient light conditions.

[0013] In some embodiments, the technology described herein relates to a system for creating a virtual screen for displaying visible images in air, comprising a computing device and a virtual screen generator comprising one or more light sources, a scanning means for scanning light from the light sources across a predefined space in the air, and a control means for controlling operation of the light sources and the scanning means, the virtual screen generator being operable to communicate with the computing device over a network to receive image data to be displayed on the virtual screen, the virtual screen generator being operable using the control means to direct light from the one or more light sources such that a collection of light-emitting points within the visible range of the electromagnetic spectrum is formed within the predefined space in the air, the collection of points collectively forming an image corresponding to the received image data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] overview Various implementations of the present invention relate to a technique for defining a "virtual screen", i.e., a two-dimensional region or three-dimensional volume in space, and displaying two-dimensional or three-dimensional still or moving images (i.e., video) on the virtual screen. Typically, the images and videos correspond to those displayed on electronic devices such as laptops, mobile phones, tablet computers, etc.

[0015] The virtual screen can operate in any environment, indoors or outdoors. However, as one skilled in the art will recognize, the quality of the viewing experience will vary depending on the environment in which the virtual screen is used. For example, the viewing experience is generally better in environments with less ambient light (for the same reasons that movie theaters are typically dimmed), or where the "background" is plain and / or where there is less movement (i.e., fewer moving cars, people, trees, etc.). Also, the outdoor viewing experience will, as would be expected, be better in sunny weather than in inclement weather (although fog or haze may improve the viewing experience). Because the virtual screen is by definition transparent, there will be fewer "distractions" with respect to the content displayed on the virtual screen if the background is not busy. This also allows for reduced power to the equipment used to generate the virtual screen and the images displayed thereon, which can result in longer battery life and / or allow the equipment to be smaller and more portable.

[0016] The virtual screen can be embodied in many different implementations, but the implementations operate according to a general method, which will be described with reference to FIG.

[0017] Exemplary Method for Displaying Content on a Virtual Screen 1, a method 100 according to one implementation begins with step 102 of activating a virtual screen generator. The virtual screen generator is described in more detail below, but depending on the particular implementation, activation may be as simple as flicking an on / off switch or may require several steps and setting up various physical components.

[0018] Once the virtual screen generator is launched, it is connected to a computing device, such as a mobile phone, laptop, tablet, or Internet of Things (IoT) enabled device (step 104). Again, depending on the particular implementation at hand, the connection may be wired and / or wireless. The physical location of the computing device may be remote from the virtual screen generator or in close proximity to the virtual screen generator. In some implementations, the virtual screen generator and the computing device may be integrated into a single device. In other implementations, the virtual screen generator and the computing device may communicate over one or more wired or wireless networks.

[0019] Once the connection is established, a virtual screen application is loaded onto the computing device (step 106). The virtual screen application includes instructions for controlling the virtual screen generator to correctly display the content. Again, there are various implementations of the virtual screen generator, so typically there is one virtual screen application associated with each implementation of the virtual screen generator, although different virtual screen applications may be considered for the virtual screen to operate in different modes. The computing device may include several virtual screen applications for use with a wide variety of virtual screen generators, and may have the capability to download and run further virtual screen applications from the internet.

[0020] The virtual screen is then calibrated in optional step 108. Calibration may be an optional feature of certain virtual screen generators and may be performed manually by a user or automatically by the virtual screen generator, possibly in cooperation with a computing device. The purpose of calibration is to adjust the virtual screen to the environment in which it will be used. For example, in a low light environment, the virtual screen generator may use less power compared to a bright environment and still achieve a clearly visible image on the virtual screen. Similarly, generating a virtual screen outdoors on a sunny day may require more power from the virtual screen generator compared to a foggy day. Various automatic calibration algorithms may be developed for different conditions, for example based on feedback from obtained ambient environment measurements and / or previous user viewing experiences.

[0021] Next, a program is loaded onto the computing device (step 110). The program typically contains content that is displayed on a virtual screen and can be a web browser, a messaging application, software for viewing online videos, drawing software, presentation software, essentially any software capable of displaying visual content -- essentially anything that can be viewed by one or more users.

[0022] Finally, the program content is displayed on the virtual screen (step 112). The virtual screen controller receives the program content from the computing device and instructions on how the program content should be displayed on the virtual screen. This completes process 100.

[0023] General System Architecture 2 illustrates an exemplary architecture of a system 200 for displaying content on a virtual screen as described above, according to one implementation. As can be seen in FIG. 2, the system 200 includes a computing device 202 that communicates over a network 204 with a virtual screen generator 206 that is used to generate a virtual screen 208 in air or some other gaseous or liquid medium for displaying still and / or moving images. As described above, in certain implementations, the computing device 202 and the virtual screen generator 206 are integrated into the same physical unit, and the network 204 is not required.

[0024] As mentioned above, the computing device 202 may be any type of computing device that includes a processor, memory, and some input / output capabilities. Typically, the computing device 202 is a portable consumer device such as a laptop, mobile phone, tablet computer, or the like, although in some implementations the computing device 202 may be a stationary computer that is permanently installed in some type of facility.

[0025] Generally, the computing device 202 has input / output (I / O) mechanisms coupled to a processor coupled to tangible, non-transient (non-transient) memory. Although Fig. 2 illustrates only one computing device 202, it should be understood that various implementations may include one or more auxiliary computing devices, and the invention is not limited to using only a single computing device. The illustrated computing device 202 includes instructions stored in memory for causing the virtual screen generator 206 to perform any one or more of the methodologies discussed herein.

[0026] In some implementations, such as shown in FIG. 2, the system of the present invention is network-deployed, with network 204 representing the Internet, a LAN, a Wi-Fi network, or a combination thereof. As mentioned above, in certain implementations, the system of the present invention is deployed using an application or a mobile app. For example, computing device 202 can be a handheld device, such as a tablet computer or a smartphone, capable of operating a mobile app and capable of operating the system of the present invention via the mobile app. In other implementations, computing device 202 can be a personal computer (PC), a tablet PC (e.g., iPad®, Samsung Galaxy tablet, Nexus 7 tablet computer sold by Google (Mountain View, Calif.)), a set-top box (STB), a personal digital assistant (PDA), a mobile phone or smartphone, a web appliance, a network router, a switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be performed by the machine, as necessary to perform the methodologies described herein.

[0027] In certain implementations, the computing device 202 is a custom device designed and constructed to perform the methodologies described herein, e.g., housed in a unique form factor or a form factor not typically associated with a laptop, desktop, or tablet computer.

[0028] A computing device 202 typically includes one or more input / output (I / O) devices, as shown in Figure 2. As mentioned above, the computing device 202 also includes other typical components, such as a screen, such as a touch screen, and a microphone, a speaker, a cellular radio frequency antenna, and a network interface device, which may be, for example, a network interface card (NIC), a Wi-Fi card, or a cellular modem. The I / O devices typically include ports, WiFi cards, microphones, speakers, touch screens, etc., and in some implementations may also include a virtual screen generator 306, as described below.

[0029] The computing device 202 generally includes at least one processor, as shown in Figure 2. A computer system or machine of the present invention includes one or more processors (e.g., a central processing unit (CPU), a graphics processing unit (GPU), or both), a main memory, and a static memory, which communicate with each other via a bus, as will be recognized by those skilled in the art as necessary or suitable for carrying out the methods of the present invention. Those skilled in the art will also recognize that the processor may be provided by one or more processors, including, for example, one or more single-core or multi-core processors.

[0030] The computing device 202 generally includes a memory, which is also shown in FIG. 2. A memory is generally a machine-readable medium and may generally exist in the form of a random access memory (RAM), a read-only memory (ROM), or a combination thereof. A memory generally refers to one or more storage devices, such as semiconductor, magnetic, magneto-optical, or optical disks, for storing data or carrying information. Information carriers for memory suitable for embodying computer program instructions and data include any suitable form of memory that is tangible, non-transient, non-volatile, or a combination thereof. In a specific implementation, the device of the present invention includes a tangible and non-transient computer-readable medium for memory. Exemplary devices for use as memory include semiconductor memory devices and flash memory devices, and may be built into or external to the computing device 202. Other examples of memory devices include magnetic disks (e.g., built-in hard disks or removable disks), magneto-optical disks, and optical disks (e.g., CD and DVD disks).

[0031] Next, some examples of virtual screen generators 206 are described. In general, virtual screen generators 206 can be divided into two broad categories: passive screens, i.e., those that generate a virtual screen onto which light is projected and which can be reflected or scattered back to the viewer's eye, and active screens, i.e., those that generate a virtual screen in which visible light is generated on the screen itself so that it can be observed by the viewer. It should be noted that the examples given below in no way form an exhaustive list of virtual screen generators 206, but should be considered as illustrative of possible implementations. Many modifications are possible for those skilled in the art. Furthermore, it is believed to be within the capabilities of those skilled in the art to modify parameters and substitute individual components in order to improve the performance of the system and optimize it for a particular environment. Thus, a wide range of modifications are believed to fall within the scope of the appended claims. Furthermore, it should be noted that while the virtual screen generator 206 and the virtual screen 208 are illustrated in the context of air, similar principles can be applied to other gaseous media. Thus, the principles described below are not limited to air alone.

[0032] Virtual Screen Generator for Creating Active Plasma Screens In a first implementation, as shown in FIG. 3, the virtual screen generator 206 includes one or more lasers 302, a scanning means 304 for scanning the lasers over an area forming a virtual screen 308, and a controller 306 for controlling the individual lasers and the scanning means 304.

[0033] In operation, the controller 306 directs the scanning means 304, e.g., one or more movable mirrors, to move the laser beam (laser light) so that it rapidly moves across an area corresponding to the virtual screen 308 in a raster-like pattern, much like that done on old-fashioned cathode ray tube (CRT) type monitors. However, instead of tracing a continuous pattern in the air, the laser 302 switches on and off to generate only brief pulses at certain times. When a pulsed laser beam is generated, if it is of high enough intensity, a plasma discharge is generated in the air (or another gas) at a point on the virtual screen, which is seen by the human eye as a flash of light. If the scanning frequency is high enough, the human eye does not distinguish between individual flashes, but instead integrates the individual flashes into a pattern that forms a line. As a result, a "line drawing" can be generated in the air, such as the image of a dog and a cat displayed on the virtual screen 308. If the virtual screen 308 is too large for a single laser to move across it fast enough, multiple lasers can be used. For example, a first laser may generate the top third of the virtual screen 308, a second laser may generate the middle third of the virtual screen 308, and a third laser may generate the bottom third of the virtual screen 308.

[0034] In some embodiments, the scanning means 304 may be replaced by a diffractive optical element or spatial light modulator (SLM), which, as mentioned above, can directly create the desired two-dimensional pattern on the virtual screen 308 without the need for line-by-line scanning. As is well known in the art, an SLM is an electronically programmable device that can modulate its light output based on a specific fixed spatial pattern (pixels), essentially projecting light that is controlled either in amplitude only, phase only, or both (phase amplitude). SLMs are often used in overhead projectors. SLMs are also well suited for the purpose of generating moving images on the virtual screen 308, as the projected pattern can be changed over time.

[0035] The distance of the virtual screen 308 from the virtual screen generator 306 (i.e. the "depth" of the screen) can be adjusted by adjusting the focal position of the laser, for example by using various lenses or mirrors, or a combination thereof. All plasma discharges occur at a distance from the laser 302, thereby creating in effect a plane that forms the virtual screen 308. In order not to interfere with the flash of light from the plasma, the laser used preferably operates at a frequency outside the range of human visibility, such as in the infrared region. Examples of lasers operating in this frequency range include CO2 lasers and Nd:YAG lasers. The ability to adjust the distance, and more generally the position, of the virtual screen 308 from the virtual screen generator 306 is also important from a safety point of view to prevent people or animals from accidentally entering the area of ​​the virtual screen 308.

[0036] In some implementations, a single laser may not have enough power by itself to generate plasma in air. In such a setup, two or more lasers are used in combination, and only when their focal positions coincide can they produce enough power to generate plasma in air. Such a setup requires more sophisticated control mechanisms of the dual lasers compared to what is required for a single laser, but can be advantageous from a safety standpoint since the power of each laser can be reduced. It is also possible to introduce a gas (other than air) to form the virtual screen 308, in which the plasma discharge can be generated at a lower intensity than is required to generate the plasma discharge in air.

[0037] In some implementations, various types of prisms can be used to create copies of the virtual screen 208 and project them to different locations in space, such as in two orthogonal directions. The virtual screen generator 206 can also be placed on a moving platform (e.g., rotating) so that the virtual screen 208 can rotate 360 ​​degrees in space and be viewable from essentially any location, or to create a virtual screen with a cylindrical or hemispherical projection "surface" similar to what can be experienced in an Omnimax theater, planetarium, etc.

[0038] This plasma generating implementation may prove very useful for displaying text messages or simple drawings, for example to provide warning messages or guidance. Given the high power required for a laser to generate plasma in air, this implementation is particularly suitable for virtual screens that are located at some distance from people, such as in the sky, where people do not interfere with the laser beam. For environments where people are closer, there are other alternative implementations that may be more suitable, as will be explained.

[0039] Virtual screen generator for generating active fluorescent screens As mentioned above, there may be situations where it is desirable to create a virtual screen 208 that is closer to the user and in an environment where other people may be present, and therefore where it may be impractical or unsafe to have a plasma-based virtual screen 208. In such situations, the virtual screen generator 206 may instead rely on another physical phenomenon: fluorescence. Fluorescence generally refers to a material that absorbs light or other electromagnetic radiation, emitting the light a short time after absorption. In most cases, the emitted light has a longer wavelength and lower photon energy than the absorbed light. Perceptible instances of fluorescence occur when the absorbed radiation is in the ultraviolet range of the spectrum (not visible to the human eye) and the emitted light is in the visible range. This causes fluorescent materials to have a distinct color that can only be seen when exposed to ultraviolet (UV) light. In contrast to phosphorescent (phosphorescent) materials, which emit light for a while, fluorescent materials stop emitting light almost instantly when the radiation source is stopped. Fluorescence can be induced by different types of light sources, such as lasers (so-called laser-induced fluorescence, "LIF") and light-emitting diodes (LEDs). By selecting materials that emit specific desired wavelengths and selecting a light source (e.g., a laser or LED) that can induce fluorescence in those materials, it is possible for the virtual screen generator 206 to generate a color virtual screen 208.

[0040] Fig. 4 is a schematic diagram of a virtual screen generator 206 for generating a virtual screen 208 capable of reproducing a color image using fluorescence. The general operating principle is the same as that described above with respect to the system of Fig. 3, but in this implementation, the virtual screen generator 306 also includes a substance emitter 402. The substance emitter 402 is configured to emit one or more non-toxic gases of a preferred substance into the air until a sufficient substance concentration is reached to emit fluorescent light visible to the human eye when illuminated by one or more light sources 404. The light sources 404 can be one or more lasers, LEDs, or other suitable light sources for exciting the substance and inducing fluorescence.

[0041] As an example, consider a scenario in which the virtual screen generator 206 has a material emitter 402 that contains three different materials: A, B, and C. When illuminated, material A emits red light, material B emits green light, and material C emits blue light. The material emitter 402 emits a "cloud" of the three materials that disperse evenly in the air near the material emitter 402, creating a three-dimensional space in which any point can be triggered by a corresponding light source to emit either red, green, or blue light. This can essentially be thought of as a high-resolution virtual screen. As described above, when scanning this space, the red, green, and blue light materials at the focus of the light source can emit in various combinations, and the human eye perceives the light similarly to how it perceives light from an RGB pixel or voxel in a conventional display.

[0042] Since the light from the light source 404 excites any material it passes through on its way from the virtual screen generator 206 to the virtual screen 208, it is desirable to have a high concentration of material at the location of the virtual screen 208 and a low concentration of material between the light source 404 and the virtual screen 208 in order to avoid as much as possible interference from fluorescence outside the virtual screen 308. Various mechanisms can be used to achieve such spatial containment and concentration differences of materials, such as electric and magnetic fields, laminar flow, etc. Furthermore, the colors are of course not limited to red, green, and blue. Since gases can fluoresce at a great many wavelengths, this implementation of the virtual screen generator 306 can be used to generate essentially any combination of colors, which can provide a much richer color experience to the viewer than being limited to various combinations of red, green, and blue.

[0043] A virtual screen generator that uses a mixture of liquid and gas to generate passive screens This implementation of the virtual screen generator 206 is similar to the screen generator 206 described above for generating the fluorescent virtual screen 208. However, instead of emitting a gas, the substance emitter 402 emits a gas-liquid mixture, such as an aerosol or mist. The position of this liquid-gas mixture can be controlled, for example, using some type of electromagnetic field, ultrasound, or a fan that creates a laminar flow, or by controlling the nozzle that emits the liquid-gas mixture so that only droplets of a certain size are emitted in a particular desired direction.

[0044] The result is a virtual screen 208 that is denser compared to the surrounding air and therefore also reflects light. Thus, the virtual screen 208 can be illuminated with one or more lasers 302 having one or more different colors, and the light reflects off the virtual screen 308 and reaches the viewer's eyes. A similar effect is observed when driving a car on a foggy day, but because the virtual screen generator 206 has the ability to control both the characteristics of the "fog" itself (e.g., size and / or color of the droplets) and the characteristics of the light used to illuminate the fog, it is possible to provide a virtual screen 208 with a variety of qualities rather than just a "white wall" of reflected light.

[0045] A virtual screen generator that generates passive screens using moving particles In this implementation, shown diagrammatically in FIG. 5 , the virtual screen generator 206 includes one or more lasers 302, a scanning means 504, a controller 306 for controlling the individual lasers and the scanning means 504, and a particle emitter 506.

[0046] This implementation is based on the concept that small particles can be suspended in the air and controlled by light or sound to move them very precisely around a three-dimensional space. The particles can be solid particles made of, for example, plastic, metal, or droplets of some type of liquid, such as oil. In operation, the controller 306 instructs the scanning means 504 to move the particles to "outline" a shape in space. If the particles change position fast enough, the human eye will "integrate" the particle's position into a line rather than discrete positions, much like what was described above for the implementation shown in FIG. 3.

[0047] Additionally, particles can be illuminated with a laser and reflected to the observer's eye, making the particles appear colored. For example, a white particle tracing the outline of a square can be illuminated with a red laser while tracing the top and bottom lines of the square, and a green laser while tracing the sides of the square, resulting in a red-green square to the observer's eye. Thus, in this implementation, not only are the particles controlled by the scanning means 504, but the scanning means 504 also controls one or more lasers, similar to those described above.

[0048] Moreover, the particle motion can be controlled in any direction, so of course, as described above, the particles can be made to rapidly move in a raster-like pattern across an area corresponding to the virtual screen 208, illuminating specific locations with specific colors. As with the plasma and fluorescent implementations described above, the particle motion will be integrated by the human observer's eye and will therefore appear to form lines that can blend together into a color image.

[0049] If the virtual screen 208 is too large for a single particle to traverse fast enough, multiple particles can be used and controlled independently. For example, a first particle can generate the top third of the virtual screen 208, a second particle can generate the middle third of the virtual screen 208, and a third particle can generate the bottom third of the virtual screen 208.

[0050] Taking these techniques a step further, in some implementations, tens, hundreds, or even thousands of small particles can be used, and rather than being moved in a raster fashion, they can be positioned and repositioned in various patterns by acoustic fields (e.g., acoustic waves similar to those that can be seen when sand is placed on a vibrating drum), electric and / or magnetic fields, or standing waves resulting from electric and / or magnetic fields, or various combinations thereof. It should also be noted that not all particles need to be of the same type, but rather a mixture of different particles can be provided that respond differently to different types of fields. Some such mixtures may include particles that respond only to acoustic fields and others that respond only to electric / magnetic fields. In this way, different fields can control different particles, resulting in more complex patterns. Additionally, while the particles have been described as having reflective properties, it should be understood that the particles themselves may also be luminous, reducing or completely avoiding the use of light sources such as the laser 302 in FIG. 5. Many variations can be envisioned by those skilled in the art.

[0051] As one skilled in the art will further appreciate, if the particles are suspended in the air and controlled by light, sound, or electric or magnetic fields, they are by definition very light. This makes them very susceptible to disturbances around them, such as wind gusts (indoors as well as outdoors). Thus, to prevent the particles from falling, an optional enclosure 508 can be provided that can be placed around the area of ​​the virtual screen 208 when the virtual screen generator 206 is used in an environment where it may be exposed to this type of disturbance. Such an enclosure 508 can be made of essentially any transparent material that allows light reflected from the particles to reach the viewer's eyes. In some implementations, the enclosure 508 can also help generate electric and / or magnetic fields to keep the particles suspended and counteract the effects of gravity. Preferably, the enclosure 508 is foldable so that the user can easily carry it with the computing device 202.

[0052] In yet another related implementation, the moving particles may be embodied as a "waterfall" of water droplets or other types of liquid that move under the influence of gravity. This waterfall again provides a surface onto which light is projected and reflected to the viewer's eye. Typically, the width and height of the waterfall determine the size of the virtual screen 208. As with the aerosol described above, the size and color of the droplets can be varied to create the desired virtual screen quality. For example, the waterfall may be composed of 512 or 1024 parallel vertical "lines".

[0053] Virtual screen generator that creates passive screens using holographic images One implementation of the virtual screen generator 206 uses concepts known from the general field of holography to create the virtual screen 208. Traditionally, holograms are generated by shining a part of a light beam (ray) from, for example, a laser (the reference beam) directly onto the recording medium and shining another part of the light beam (the illumination beam or object beam) onto the object in such a way that some of the scattered light also falls onto the recording medium. As recording medium several different materials can be used. One of the most common materials is film, which is very similar to photographic film (silver halide photographic emulsion) but has a much higher concentration of photo-reactive particles, allowing the much higher resolution required by holograms.

[0054] When the two laser beams reach the recording medium, their light waves cross and interfere with each other, imprinting an interference pattern on the recording medium. This pattern itself is seemingly random, and represents how the light of the scene interferes with the original light source, but not the original light source itself. The interference pattern on the recording medium can be thought of as an encoded version of the scene, and in order to see its contents, a specific key - the original light source - is required. This missing key is later provided by shining the same laser used to record the hologram on the developed film. When this beam shines on the hologram, it is diffracted by the hologram's surface pattern. This creates a light field identical to that originally generated in the scene, which is scattered onto the hologram and seen by the viewer as a virtual image of the object.

[0055] The virtual screen generator 206 in this implementation uses the same basic principle, but instead of having a physical medium record the interference pattern, the computing device 202 generates an artificial interference pattern on its display that corresponds to the image that is intended to be displayed on the virtual screen 208. The virtual screen is thereby formed in the air at a fixed distance from the display of the computing device 202. Thus, in use, a user typically places his / her computing device 202 on a table or other surface, after which the virtual screen 208 appears above the computing device 202 and is visible to multiple viewers. It should be noted that this implementation works for both still and moving images, where the interference pattern is dynamically generated by the computing device.

[0056] However, it should be noted that a prerequisite for this implementation is to have a computing device with a display capable of controlling the phase of light from the display so that interference can be achieved in various directions. Otherwise, the limitations of the display may also limit the possible viewing angles of a user attempting to view the contents of the virtual screen 208. In general, a two-dimensional virtual screen 208 is easier to generate in this embodiment than a three-dimensional virtual screen.

[0057] Virtual screen generator that uses three-wave or four-wave mixing to generate passive screens The concept behind this type of virtual screen generator 206 is called three-wave or four-wave mixing and is related to the hologram implementations mentioned above in the sense that it uses a similar basic concept. However, instead of using a computing device to generate the interference pattern, an optical setup is used that allows three or four waves to interfere in a nonlinear optical medium such as a gas. Three-wave and four-wave mixing occurs in different materials depending on their second or third order nonlinearity, respectively. In materials with second order (i.e. quadratic) nonlinearity, two waves interact to create a third wave (hence three-wave mixing), and in materials with third order (i.e. cubic) nonlinearity, three waves interact to create a fourth wave (hence four-wave mixing).

[0058] In four-wave mixing, two pump waves (also called reference waves) interact with an object wave to form a conjugate wave from two pump photons with the same or different frequencies. A special case of four-wave mixing exists where only one pump wave is used. This special case is called degenerate four-wave mixing.

[0059] Many variations are possible, but the general idea is that one or several waves interact via material nonlinearities (e.g. in a gas) and create new light by mixing three or four waves. This new light is visible to the observer, appearing as a virtual screen 208, similar to what is done in a holographic setup.

[0060] conclusion It should be noted that the above examples are merely intended to illustrate some possible usage scenarios, and the general principles of the invention are applicable in many different fields, from navigation applications, to advertising, display of warning / security messages, information presentation, entertainment purposes (movies, games, etc.), essentially anything that "traditional displays" can perform today. Furthermore, depending on the available space and the particular implementation of the virtual screen generator, the size of the virtual screen can vary from a few inches to several feet or even yards in diameter.

[0061] It should also be noted that while the above description has been limited to two-dimensional virtual screens, as technology advances there may be various ways to extend these concepts to three-dimensional stereoscopic virtual screens by applying the same general principles to the depth dimension. In such implementations, the content on the virtual display can be viewed from any direction, allowing users to gather on all four sides of the virtual screen, which is particularly useful in presentation and entertainment situations. Thus, the implementations described herein should not be considered limited to only two-dimensional screens.

[0062] Additionally, various types of optical components (e.g., lenses, prisms, beam splitters, mirrors, SLMs, etc.) can be combined with the above-mentioned techniques to change the size, shape, and appearance of the virtual screen 208 or the way it is perceived by the user. Various techniques from adjacent areas, such as HUDs (heads-up displays), can be combined with the various implementations described herein to further enhance the above-mentioned implementations. Such modifications are within the capabilities of one of ordinary skill in the art.

[0063] Finally, in addition to the physical processes mentioned above, there are other processes whereby light interacts with matter and changes its wavelength. For example, plasma, fluorescence, three-wavelength or four-wavelength mixing, as well as so-called Raman scattering or Brillouin scattering, can change the wavelength of the incident light. These physical phenomena can be used in combination with the various embodiments mentioned above, since changing the wavelength can be a useful component in generating the virtual screen 308.

[0064] The present invention may be a system, a method, and / or a computer program product at any possible level of technical detail integration. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions thereon for causing a processor to carry out aspects of the present invention.

[0065] A computer-readable storage medium can be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: portable computer diskettes, hard disks, random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), static random access memories (SRAMs), portable compact disk read-only memories (CD-ROMs), digital versatile disks (DVDs), memory sticks, floppy disks, mechanically encoded devices such as punch cards or ridge structures in grooves having instructions recorded thereon, and any suitable combination of the foregoing. A computer-readable storage medium as used herein is not to be construed as being a transitory signal itself, such as an electric wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a wave guide or other transmission medium (e.g., light pulses passing through a fiber optic cable), or an electric signal transmitted through an electric wire.

[0066] The computer-readable program instructions described herein can be downloaded to each computing / processing device from a computer-readable storage medium or to an external computer or storage device over a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may consist of copper transmission cables, optical transmission fiber, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in each computing / processing device.

[0067] The computer readable program instructions for carrying out the operations of the present invention may be either assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state setting data, configuration data for an integrated circuit, or source or object code written in any combination of one or more programming languages, including object oriented programming languages ​​such as Smalltalk, C++, and procedural programming languages ​​such as the "C" programming language. The computer readable program instructions may execute entirely on the user's computer, partially on the user's computer as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet Service Provider). In some implementations, electronic circuitry including, for example, a programmable logic circuit, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or a programmable logic array (PLA) can utilize state information of the computer readable program instructions to execute computer readable program instructions and personalize the electronic circuitry to perform aspects of the present invention.

[0068] Aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to implementations of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer readable program instructions.

[0069] These computer readable program instructions can be provided to a processor of a computer, or other programmable data processing apparatus, to generate a machine such that the instructions, executed via the processor of the computer or other programmable data processing apparatus, create means for performing the functions / acts specified in the flowchart and / or block diagram blocks or blocks. These computer readable program instructions can also be stored in a computer readable storage medium capable of directing a computer, programmable data processing apparatus, and / or other device to function in a particular manner, such that the computer readable storage medium having instructions stored therein constitutes an article of manufacture including instructions for performing aspects of the functions / acts specified in the flowchart and / or block diagram blocks or blocks.

[0070] The computer readable program instructions may be loaded into a computer, other programmable data processing apparatus, or other device to cause the computer, other programmable apparatus, or other device to execute a series of operational steps to generate a computer-implemented process, such that the instructions executing on the computer, other programmable apparatus, or other device perform the functions / acts specified in the flowchart and / or block diagram blocks or blocks.

[0071] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various implementations of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or portion of instructions constituting one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may in fact be accomplished as one step and executed in a simultaneous, substantially simultaneous, partially or fully overlapped manner in time, or the blocks may sometimes be executed in reverse order depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flowchart diagrams, as well as combinations of blocks in the block diagrams and / or flowchart diagrams, may be implemented by a special purpose hardware-based system that performs the specified functions or acts or executes a combination of special purpose hardware and computer instructions.

Claims

1. A method (100) for creating a virtual screen (208) for displaying a visible image in the air, comprising: providing a virtual screen generator (206) comprising one or more light sources (302), scanning means (304) for scanning the light from said light sources (302) over a predefined space in air, and control means for controlling the operation of said light sources (302) and said scanning means (304); receiving image data to be displayed on the virtual screen (208) by the virtual screen generator (206); using said control means to direct said light from said one or more light sources (302) such that a collection of emitting points in the visible range of the electromagnetic spectrum is formed within said predefined volume in the air, said collection of points collectively forming an image corresponding to said received image data; A method comprising:

2. 2. The method (100) of claim 1, wherein the image data displayed is an enlarged version of an image displayed on a user electronic device (202), such as a laptop, a mobile phone, a tablet computer, or the like.

3. The method (100) of claim 2, wherein the virtual screen generator (206) is connected to the user electronic device (202) by a wired or wireless network (204).

4. The method (100) of any one of claims 1 to 3, wherein the one or more light sources (302) are lasers.

5. 4. The method (100) of any one of claims 1 to 3, wherein the scanning means (304) comprises one or more movable mirrors configured to move the light from the light source (302) in a raster-like pattern across the predefined space in air while switching the light source (302) on and off to generate short pulses of light.

6. 6. The method (100) of any one of claims 1 to 5, wherein the virtual screen generator (206) comprises two or more light sources (302) and a scanning means (304) for each light source, each light source and scanning means (304) being configured to cover a specific portion of the predefined space.

7. 5. The method (100) of any one of claims 1 to 4, wherein the scanning means (304) comprises one or more diffractive optical elements or spatial light modulators, and the control means is configured to control the operation of the light source (302) and the spatial light modulator to generate a two-dimensional pattern of light emitting points in the predefined space in air.

8. 8. The method (100) of any one of claims 1 to 7, wherein the predefined volume in air is defined by adjusting the focal positions of the one or more light sources (302) to create an essentially vertical plane in the air that forms the virtual screen (208).

9. 9. The method (100) of any one of claims 1 to 8, wherein the one or more light sources (302) operate at frequencies outside the visible range and the light emission points are generated by plasma discharges in the predefined space in air.

10. 9. The method (100) according to any one of claims 1 to 8, wherein the virtual screen generator (206) further comprises a substance emitting means configured to fill the predefined space with a non-toxic gaseous medium, in which the luminous points are generated by fluorescence induced by the light from the one or more light sources (302).

11. 11. The method (100) of claim 10, wherein the gaseous medium and the one or more light sources (302) are selected such that fluorescent light occurs at different wavelengths to generate a virtual screen (208) having multiple colors.

12. The method (100) according to any one of claims 1 to 8, wherein the virtual screen generator (206) further comprises a substance emitting means configured to fill the predefined space with a non-toxic gas-liquid mixture to provide a reflective virtual screen (208) onto which light of different colors from the one or more light sources (302) can be projected and reflected to an observer.

13. 13. The method (100) of any one of claims 10 to 12, wherein the virtual screen generator (206) further comprises a containment means configured to generate an electric, magnetic or ultrasonic field to essentially confine the substance emitted by the substance emitting means to the predefined space in air while displaying the image.

14. 5. The method (100) of any one of claims 1 to 4, wherein the virtual screen generator (206) further comprises a particle emitter (506) configured to emit small reflective particles within the predefined space in the air, and the control means is operable to control the movement of the small particles using an electric, magnetic or ultrasonic field such that the particles can move around within the predefined space in the air while being illuminated and reflecting light from the one or more light sources (302) towards a viewer.

15. The method (100) of any one of claims 1 to 14, further comprising calibrating the virtual screen (208) based on ambient lighting conditions.

16. A system (200) for creating a virtual screen (208) for displaying a visible image in the air, comprising: A computing device (202); a virtual screen generator (206) comprising one or more light sources (302), scanning means (304) for scanning the light from said light sources (302) across a predefined space in air, and control means for controlling the operation of said light sources (302) and said scanning means (304); the virtual screen generator (206) is operable to communicate with the computing device (202) over a network (204) to receive image data to be displayed on the virtual screen (208); the virtual screen generator (206) is operable, using the control means, to direct the light from the one or more light sources (302) such that a collection of emitting points within the visible range of the electromagnetic spectrum is generated within the predefined volume in the air, the collection of points collectively forming an image corresponding to the received image data. system.

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