Volumetric display using noble gasses

Methods and systems may provide for 3D volumetric displays. Such 3D volumetric displays may include a transparent enclosed volume holding a noble gas as a gain medium. Two electrodes positioned on opposing sides of the transparent enclosed volume, may apply a voltage to excite electrons of the gain medium to an excited state. A pump laser may emit a laser beam into the gain medium at a wavelength that has an energy below an absorption line of the gain medium to allow for photon collision while also allowing the laser beam to enter the gain medium. A lens may focus the laser beam to a focused spot within the transparent enclosed volume and move the focused spot as a three-dimensionally scanned voxel to produce a 3D image.

TECHNICAL FIELD

Embodiments generally relate to three-dimensional (3D) volumetric displays. More particularly, embodiments relate to volumetric displays using noble gasses.

BACKGROUND

There are many technologies for creation of a three-dimensional (3D) image. Typically, these technologies for creation of a 3D image fall into three approaches: free space displays, swept volume displays, and static volumetric displays. Due to these technologies taking distinct approaches, the technological approaches utilized for free space displays and/or swept volume displays often are not applicable or easily adapted for static volumetric displays.

Free space displays often operate in open air, with no barrier between the 3D image and a user. For example, such free space displays may utilize trapped particle, free particle, or plasma emission technologies to create the 3D image.

Swept volume displays often operate with a rotating emissive or reflective screen. Such a rotating emissive or reflective screen may fuse a series of slices of the 3D object into a single 3D image by creating an optical illusion that relies on the human persistence of vision. For example, such swept volume displays may utilize spinning LEDs, illuminated spinning paddles, or translating projection surfaces to create the 3D image.

Static volumetric displays are devices that display a 3D image within a static volume. There are many different methods of producing a volumetric display, such as suspending particles and reflecting a scanned laser off the suspended particles, for example. However, such suspending particle-type volumetric displays may not be practical due to the difficulty in controlling the particle across large volumes and moving the particle at high speeds.

BRIEF SUMMARY

In one embodiment, an apparatus for 3D volumetric displays includes a transparent enclosed volume, two electrodes, a single pump laser, and a lens. The transparent enclosed volume holds a noble gas as a gain medium. The two electrodes are positioned on opposing sides of the transparent enclosed volume. The two electrodes configured to apply a voltage to excite electrons of the gain medium to an excited state. The single pump laser is configured to emit a laser beam into the gain medium at a wavelength that has an energy below an absorption line of the gain medium, to allow for photon collision while also allowing the laser beam to enter the gain medium. The lens is configured to focus the laser beam to a focused spot within the transparent enclosed volume. The lens is configured to move the focused spot at various depths, and the pump laser is configured to move the focused spot within the gain medium as a three-dimensionally scanned voxel to produce a 3D image. The gain medium with excited electrons is configured to receive the laser beam having a pumped wavelength at a first wavelength and configured to emit a second wavelength that is one-half of the first wavelength as luminescence, where the luminescence is in response to excitation from the single pump laser.

In some implementations of the apparatus, the enclosed volume holds the noble gas as the gain medium without suspended particles.

In some implementations of the apparatus, the enclosed volume holds the noble gas as the gain medium without suspended fluorophore particles.

In some implementations of the apparatus, the voltage is applied to the two electrodes to reach but not exceed a level where the noble gas begins to glow.

In some implementations of the apparatus, no heat is applied to excite electrons of the gain medium.

In some implementations of the apparatus, the excited state is a metastable state and the luminescence is in response to two-photon excitation from the pump laser.

In some implementations of the apparatus, the laser beam will be absorbed at an edge of the gain medium when pumping at a wavelength that is within the absorption line of the gain medium.

In some implementations of the apparatus, no emission occurs when the laser beam is not focused within the gain medium.

In some implementations of the apparatus, different pumping wavelengths are used to create different wavelengths of illumination, where a blue-type second wavelength of between 450 nanometers and 495 nanometers is emitted in response to a pumped first wavelength of between 900 nanometers and 990 nanometers, where a green-type second wavelength of between 495 nanometers and 570 nanometers is emitted in response to a pumped first wavelength of between 990 nanometers and 1140 nanometers, and where a red-type second wavelength of between 620 nanometers and 750 nanometers is emitted in response to a pumped first wavelength of between 1240 nanometers and 1500 nanometers.

In another embodiment, a system includes a vehicle and a 3D volumetric display apparatus coupled to the vehicle. The 3D volumetric display includes a transparent enclosed volume, two electrodes, a single pump laser, and a lens. The transparent enclosed volume holds a noble gas as a gain medium. The two electrodes are positioned on opposing sides of the transparent enclosed volume. The two electrodes are configured to apply a voltage to excite electrons of the gain medium to an excited state. The single pump laser is configured to emit a laser beam into the gain medium at a wavelength that has an energy below an absorption line of the gain medium to allow for photon collision while also allowing the laser beam to enter the gain medium. The lens is configured to focus the laser beam to a focused spot within the transparent enclosed volume. The lens is configured to move the focused spot at various depths, and the pump laser is configured to move the focused spot within the gain medium as a three-dimensionally scanned voxel to produce a 3D image. The gain medium with excited electrons is configured to receive the laser beam having a pumped wavelength at a first wavelength and configured to emit a second wavelength that is one-half of the first wavelength as luminescence, where the luminescence is in response to excitation from the single pump laser.

In some implementations of the system, the enclosed volume holds the noble gas as the gain medium without suspended fluorophore particles.

In some implementations of the system, the voltage is applied to the two electrodes to reach but not exceed a level where the noble gas begins to glow.

In some implementations of the system, no heat is applied to excite electrons of the gain medium to the excited state.

In some implementations of the system, the excited state is a metastable state and the luminescence is in response to two-photon excitation from the pump laser.

In some implementations of the system, the laser beam will be absorbed at an edge of the gain medium when pumping at a wavelength that is within the absorption line of the gain medium.

In some implementations of the system, no emission occurs when the laser beam is not focused within the gain medium.

In a further embodiment, a method for 3D volumetric display, includes holding a noble gas, via a transparent enclosed volume, as a gain medium; applying a voltage, via two electrodes positioned on opposing sides of the transparent enclosed volume, to excite electrons of the gain medium to an excited state; emitting a laser beam, via a single pump laser, into the gain medium at a wavelength that has an energy below an absorption line of the gain medium to allow for photon collision while also allowing the laser beam to enter the gain medium; and focusing the laser beam, via a lens, to a focused spot within the transparent enclosed volume, where the lens is configured to move the focused spot at various depths, and the pump laser is configured to move the focused spot within the gain medium as a three-dimensionally scanned voxel to produce a 3D image. The gain medium with excited electrons receives the laser beam having a pumped wavelength at a first wavelength and emits a second wavelength that is one-half of the first wavelength as luminescence, where the luminescence is in response to excitation from the single pump laser.

In some implementations of the method, the enclosed volume holds the noble gas as the gain medium without suspended fluorophore particles.

In some implementations of the method, no heat is applied to excite electrons of the gain medium to the excited state.

In some implementations of the method, the excited state is a metastable state and the luminescence is in response to two-photon excitation from the pump laser.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The various advantages of the embodiments of the present invention will become apparent to one skilled in the art by reading the following specification and appended claims, and by referencing the following drawings, in which:

FIG. 1Ais a block diagram of an example system of a 3D volumetric display according to an embodiment;

FIG. 1Bis a block diagram of an example system of a vehicle installed 3D volumetric display according to an embodiment;

FIG. 2is an illustrative diagram of an example 3D volumetric display according to an embodiment;

FIG. 3is another illustrative diagram of an example 3D volumetric display in operation according to an exemplary embodiment;

FIG. 4is a flowchart of an example of a method of operating a 3D volumetric display according to an embodiment;

FIG. 5is an illustrative diagram of an example 3D volumetric display according to an embodiment;

FIG. 6Ais an illustrative diagram of a stationary grating structure according to an embodiment;

FIG. 6Bis another illustrative diagram of a stationary grating structure according to an embodiment;

FIG. 7is an illustrative diagram of a stationary metasurface structure according to an embodiment;

FIG. 8is another illustrative diagram of another example stationary metasurface structure according to an embodiment;

FIG. 9is an illustrative diagram of another example 3D volumetric display in operation with a rotatable diffractive plate according to an exemplary embodiment;

FIG. 10is another illustrative diagram of an example bracket for a 3D volumetric display according to an exemplary embodiment; and

FIG. 11is an illustrative diagram of rotatable diffractive plate in operation according to an exemplary embodiment.

DETAILED DESCRIPTION

As described above, suspending particle-type volumetric displays may not be practical due to the difficulty in controlling the particle across large volumes and moving the particle at high speeds.

As will be described in greater detail below, in some implementations disclosed herein, a 3D volumetric display may use noble gasses as a gain medium. Advantageously, in some implementations disclosed herein, such a 3D volumetric display may use noble gasses without suspended particles.

In some examples, the noble gas gain medium may be contained within a transparent enclosure. The enclosure may have two electrodes on opposing sides to apply a voltage to excite electrons. The voltage may be applied at a level that is just before the noble gas begins to glow. Thus, the noble gas may be excited by an applied voltage. A pump laser may be used to pump the gain medium and cause luminescence. The pump laser may be focused into the gain medium. The wavelength of the pump laser is twice the desired emission wavelength. The pump laser and a lens may be used to three-dimensionally scan a 3D image. Different pumping wavelengths may be used to create different wavelengths of illumination (e.g., red, green, yellow, and blue, as well as other colors).

More specifically, methods and systems will be described below that may provide for 3D volumetric displays adapted for use with noble gasses.

Turning now toFIG. 1A, a system100may include a 3D volumetric display104. The 3D volumetric display104may include a display controller106, a display interface108, optical and mechanical equipment109, and a volumetric graphical display110. The 3D volumetric display104may be any type of handheld device, tabletop device, vehicle-installed device, or other form of single computing device, or may be composed of multiple computing devices (e.g., multiple computing devices linked in operative communication with one another).

In some implementations, the display controller106may be a processing system and may include a processor112coupled to a memory114. The display controller106may also include a graphics processing unit (GPU) with enough bandwidth to accommodate rendering of 3D image and/or video data via the volumetric graphical display110.

The processor112may include an embedded controller, a central processing unit (CPU), any other type of similar device or multiple devices capable of manipulating or processing information, and/or the like, for example. The memory114may include a non-volatile memory (NVM), a volatile memory, any other suitable type of storage device, and/or the like, for example. The memory114may contain a set of instructions, which when executed by the processor112, cause the display controller106to present image information, such as 3D still images and/or 3D video, on volumetric graphical display110.

Such a presentation may be initiated in response to user input from display interface108to the display controller106, for example. The display interface108may include one or more user interfaces (UI) to receive input from a user and function as a user point of human-computer interaction and communication. The display interface108may include a touch screen, keyboard, mouse, physical buttons, physical dials, the like, and/or combinations thereof.

As will be described in greater detail below, the optical and mechanical equipment109may include one or more lasers, lenses, mirrors, motors, the like, and/or combinations thereof. For example, the optical and mechanical equipment109may include one or more devices for moving optics to focus and direct a laser.

The volumetric graphical display110may be configured to present a 3D volumetric image to a user. The volumetric graphical display110may be of any suitable shape and/or size. In some examples, the volumetric graphical display110may be of a cubic shape, a cuboid shape, or any suitable volumetric shape. In some implementations, the volumetric graphical display110may be a static volumetric display. In some implementations, the volumetric graphical display110may be free standing or may be shaped to conform to many surfaces (e.g., a ceiling of a room, a wall of a room, and/or a window, and/or the like).

Turning now toFIG. 1B, the system100may include a vehicle102. In such an example, the 3D volumetric display104may be directly or indirectly paired with the vehicle102. For example, the 3D volumetric display104may be associate with, coupled to, and/or operatively coupled to the vehicle102. In one example, the 3D volumetric display104may be implemented physically outside of the vehicle102, yet still function to present the 3D graphical image in the vehicle102. Alternatively, as illustrated above with respect toFIG. 1, the 3D volumetric display104may be implemented as a free standing user-controlled remote device to bring about the 3D graphical image in the vehicle102. Similarly, the volumetric graphical display110portion of the 3D volumetric display104may be implemented inside the vehicle102, whereas the remaining features of the 3D volumetric display104may be located outside of the vehicle102in a user-controlled remote device. The vehicle102may be a personal vehicle such as a car, a taxi, a shuttle, a truck, a van, a sport utility vehicle/SUV, an aircraft, and/or the like, for example. In some implementations, the volumetric graphical display110may be shaped to conform to a surface of the vehicle102(e.g., a surface in the interior cabin of the vehicle, such as a ceiling or a window of the vehicle).

While the illustrated example shows the 3D volumetric display104being coupled to the vehicle102, it will be appreciated that the 3D volumetric display104could be implemented as a stand-alone device. For example, the 3D volumetric display104may be any type of handheld device, tabletop device, vehicle-installed device, or other form of single computing device, or may be composed of multiple computing devices.

For thin surfaces, such as the window of the vehicle102, the glass may be encapsulated in a Dewar type glass if the gas pressure is near vacuum, for example. In such an implementation, a potential shape may be limited by Beer Lambert's law, with the absorption of the composed gas being the limiting thickness of the volume.

As illustrated inFIG. 2, the 3D volumetric display104may include the volumetric graphical display110, illustrated here as a transparent enclosed volume, as well as the optical and mechanical equipment109. In some implementations the transparent enclosed volume of volumetric graphical display110may hold a noble gas as a gain medium. In one example, helium and one or more noble gasses may be used for the gain medium.

In the illustrated implementation, the 3D volumetric display104may include electrodes202connected to a power supply204. The electrodes202may be configured to apply a voltage to excite electrons of the gain medium to an excited state. For example, the electrodes202may include two electrodes formed as opposing plates and positioned on opposing sides of the transparent enclosed volume. The voltage may be applied to the two electrodes202to reach but not exceed a level that is just before the noble gas begins to glow, so as to not impact the user's visual experience.

In some implementations, electrodes202may be configured to apply a voltage to excite electrons of the gain medium to an excited state that includes a metastable state. For example, in implementation where the voltage is not applied or where it is applied minimally enough that two photons are still necessary to generate luminescence, then there would be a metastable state. As used herein the term “metastable state” refers to a state that acts as a temporary energy trap of a system the energy, where the trapped energy may be lost in discrete amounts. The temporary energy trap may have a longer lifetime than ordinary excited states while also having a shorter lifetime than the lowest energy state (e.g., the ground state).

In the illustrated implementation, the 3D volumetric display104may include a pump laser206. The pump laser206may be configured to emit a laser beam208into the gain medium of volumetric graphical display110. For example, the pump laser may be configured to emit a laser beam208at a wavelength that has an energy below an absorption line of the gain medium to allow for photon collision while also allowing the laser beam208to enter the gain medium. In such an implementation, light should pass through the gain medium if it is not focused, whereas focused light will collide at a much higher probability than a standard beam entering the gain medium. At the same time, the energy of the laser beam208should be less than the energy needed to reach the excited state, so that the light does not get absorbed by the gain medium. In this case, this implies a longer wavelength. Two photons would then add together to provide enough energy to the excited electrons to cause luminescence. As will be discussed in more detail below, the pump laser206may be tunable to a plurality of wavelengths.

In some examples, the pump laser206may be motor controlled to accesses an X/Y dimension. For example, the pump laser206may be motor controlled to accesses the up and down direction and in a left and right direction within the gain medium. In some implementations, the lens210and corresponding mirror may be placed on a single track that allows them to move together. In such an example, a motor may move the track to access the X/Y dimension.

In the illustrated implementation, the 3D volumetric display104may include a lens210. The lens210may be configured to focus the laser beam208to a focused spot212within the transparent enclosed volume of volumetric graphical display110.

In some examples, the lens210may be a controlled variable focal lens. For example, the lens210may be controlled to accesses a Z dimension via a polymer and electrical actuator, a motor, the like, and/or combinations thereof. Accordingly, the lens210may be configured to move the focused spot212at various depths within the gain medium. For example, a motor214may be used to control the rotational stage of the lens210to move the focused spot212.

Accordingly, in conjunction, the pump laser206and lens210may be motor controlled to move the focused spot212to accesses a X/Y/Z dimension. For example, the pump laser206and lens210may move the focused spot212at various depths as well as in an up and down direction and in a left and right direction within the gain medium as a three-dimensionally scanned voxel to produce a 3D image.

The pump laser206may be used to pump the gain medium of volumetric graphical display110and cause luminescence. For example, such luminescence may be achieve by two-photon excitation. As described above, when atoms are exposed to a voltage, this has the potential to excite the atoms. In this excited state, it may be possible to secondarily excite the atoms with the pump laser206. Such laser excitation may not need to operate at exactly double the wavelength of the emitted light. Therefore in this case, two-photon luminescence may or may not still be necessary. For example, in implementation where the voltage applied was enough to excite the electrons to a state equivalent to half the luminescence energy, two-photon luminescence may still be necessary.

The gain medium with excited electrons is configured to receive the laser beam208having a pumped wavelength at a first wavelength. In response, the gain medium may be configured to emit a second wavelength that is half of the first wavelength in response to excitation from the pump laser206. In some embodiments, the pump laser206may be tunable to a plurality of non-visible pumping wavelengths so that a user will not perceive the laser beam208entering the gain medium. Different pumping wavelengths may be used to create different wavelengths of illumination (e.g., red, green, yellow, and blue, as well as other colors) visible to a user as a result of the excitation from the pump laser206. For example, laser206may include a femtosecond laser to pump the gain medium and cause luminescence.

Different pumping wavelengths may be used to create different wavelengths of illumination (e.g., red, green, yellow, and blue, as well as other colors). In some implementations, the colors generated are not limited to red, green and blue. For example, multiple lasers could be individually used to generate different colors. By accessing different specific atomic states, colors other than red, green and blue may be generated.

In some implementations, a blue-type second wavelength of between 450 nanometers and 495 nanometers may be emitted in response to a pumped first wavelength of between 900 nanometers and 990 nanometers, a green-type second wavelength of between 495 nanometers and 570 nanometers may be emitted in response to a pumped first wavelength of between 990 nanometers and 1140 nanometers, and a red-type second wavelength of between 620 nanometers and 750 nanometers may be emitted in response to a pumped first wavelength of between 1240 nanometers and 1500 nanometers.

As illustrated inFIG. 3, the laser beam208may be pumped at a wavelength that has an energy below an absorption line of the gain medium302. Such operation may allow the laser beam to enter the gain medium302. The laser beam208will be absorbed at an edge of the gain medium (e.g., the laser beam208will not enter the internal portion of the volume) if pumped at a wavelength that is within the absorption line of the gain medium302, and would instead be absorbed at the surface of volumetric graphical display110.

The laser beam208may be focused to allow for photon collision within the gain medium302at the focused spot212. This is significant as no emission may occur when the laser beam208is not focused within the gain medium302. Instead, an unfocussed laser beam208may pass all through the gain medium302.

FIG. 4shows a method400of operating the 3D volumetric display104. In an embodiment, the method400may be implemented in logic instructions (e.g., software), configurable logic, fixed-functionality hardware logic, etc., or any combination thereof. While certain portions of 3D volumetric display104are illustrated in method400, other portions of 3D volumetric display104fromFIG. 1have been intentionally left out to simplify the explanation of the method.

At illustrated processing operation402, a noble gas may be held as a gain medium. For example, a noble gas may be held as a gain medium within a transparent enclosed volume.

At illustrated processing operation404, a voltage may be applied to excite electrons of the gain medium. For example, a voltage may be applied to excite electrons of the gain medium via two electrodes positioned on opposing sides of the transparent enclosed volume. In some implementations, the electrodes may be set to a specific driving voltage at a level that is just before the noble gas begins to glow. In some examples, a voltage may be applied to excite electrons of the gain medium to an excited state that includes a metastable state.

At illustrated processing operation406, a laser beam may be emitted into the gain medium. For example, a laser beam may be emitted into the gain medium, via a pump laser, at a wavelength that has an energy below an absorption line of the gain medium to allow for photon collision while also allowing the laser beam to enter the gain medium.

At illustrated processing operation408, the laser beam may be focused. For example, the laser beam may be focused, via a lens, to a focused spot within the transparent enclosed volume.

At illustrated processing operation410, the focused spot may be moved to produce a 3D image. For example, the focused spot may be moved to produce a 3D image, where the lens is configured to move the focused spot at various depths while the pump laser is configured to move the focused spot in an up and down direction and in a left and right direction within the gain medium as a three-dimensionally scanned voxel to produce a 3D image.

In operation, the gain medium with excited electrons may receive the laser beam having a pumped wavelength at a first wavelength and emits a second wavelength that is half of the first wavelength in response to excitation from the pump laser. Display information may be passed to the lasers, in the appropriate infrared wavelength, to give the desired corresponding red, green, blue (RGB) values.

Advantageously, the enclosed volume may hold the electrically excited noble gas as the gain medium without the use of suspended particles. For example, suspended particles, such as suspended fluorophore particles, may often be toxic. Accordingly, eliminating the need for such suspended particles, through the use of electrically excited noble gas, may be advantageous.

Advantageously, electrodes may be utilized to excite electrons of a noble gas gain medium to an excited state. In some examples, a voltage may be applied to excite electrons of the gain medium to an excited state that includes a metastable state. For example, such electrical excitation may avoid the use of heat to excite the electrons via Doppler broadening. Accordingly, in some implementations, no heat is applied to excite electrons of the gain medium to the excited state.

Advantageously, in some implementations, it is possible to use only a single laser to generate luminescence from the noble gas gain medium. The single laser may be focused to a tight spot. In implementations described herein using contained noble gas that is electrically excited, the focusing may allow for the photons to collide to result in luminescence. Such implementations may remove the need to have a second laser for excitation resulting in luminescence. While implementations are described as only using a single laser to generate luminescence, it will be appreciated that multiple lasers may be used. For example multiple lasers could each be individually used to generate different colors. Additionally or alternatively multiple lasers could each be individually used to increase rendering speed.

As illustrated inFIG. 5, the 3D volumetric display104may include the volumetric graphical display110, illustrated here as a transparent enclosed volume, as well as the optical and mechanical equipment109. In some implementations the transparent enclosed volume of volumetric graphical display110may hold a gas as a stationary gain medium. In one example, the gas may include noble gasses, helium, and/or combinations thereof.

In the illustrated implementation, the 3D volumetric display104may include a light source502. The light source may be502may be configured to emit a light beam510. For example, light source502may be a laser configured to emit a pumped laser beam. In such an example, the pump laser may be tunable to a plurality of wavelengths. Different laser wavelengths may be used to create different wavelengths of illumination (e.g., red, green, yellow, and blue, as well as other colors). For example, different pumping wavelengths may be used to create different wavelengths of illumination (e.g., red, green, yellow, and blue, as well as other colors) visible to a user as a result of luminescence, although other luminescence mechanisms may be utilized with the 3D volumetric display104disclosed herein. For example, such luminescence may be achieve by two-photon excitation. In one example, light source502may include a femtosecond laser to pump the gain medium and cause luminescence.

In some examples, the 3D volumetric display104may include a scanning mirror504. The scanning mirror504may be configured to direct the light beam510from the light source502. For example, a motor may be used to control the positioning of the scanning mirror504to adjust the light beam510in the X and/or Y dimensions, e.g., in a horizontal dimension518and/or vertical dimension520with respect to a voxel projector508, as will be described in more detail below.

In some examples, the 3D volumetric display104may include a lens506. The lens506may be located between the scanning mirror504and the voxel projector508. The lens506may be configured to focus the light beam510to a tightly focused spot. In some implementations, lens506may be a variable focal length lens located between the scanning mirror504and the voxel projector508to adjust the light beam510, and thus expanded beam512, in a Z-direction, e.g., in a longitudinal dimension522into and out of the stationary gain medium within the volumetric graphical display110. For example, a motor the rotational stage of the lens506may be controlled to adjust the light beam510in the Z-direction via a polymer and electrical actuator, a motor, the like, and/or combinations thereof.

Alternatively, lens506may include two or more lenses configured to adjust the light beam510in the Z-direction. For example, the two or more lenses may be stacked in the Z-direction and selectively actuated on a lens-by-lens basis to adjust the light beam510in the Z-direction, e.g., into and out of the stationary gain medium within the volumetric graphical display110.

In the illustrated implementation, the 3D volumetric display104may include a voxel projector508. The voxel projector may be configured to receive the light beam510from the scanning mirror504and may be configured to project an expanded beam512into the stationary gain medium within the volumetric graphical display110.

The expanded beam may be expanded in an X and/or Y dimension, e.g., in a horizontal and/or vertical dimension. For example, changes in the X and/or Y orientation between the light beam510from the scanning mirror504and the voxel projector508may result in relatively larger changes in the X and Y dimension of the expanded beam510that is projected into the stationary gain medium within the volumetric graphical display110to produce a 3D image. Accordingly, a change in the orientation of the scanning mirror504to direct the light beam510from the light source502covers a first area in the X and Y dimension of the volumetric graphical display110when not modified by the voxel projector510and covers a second larger area in the X and Y dimension of the volumetric graphical display110when modified by the voxel projector510.

As will be discussed in more detail below, the voxel projector508may be used to permit the scanning mirror504to cover more of the volume of the 3D volumetric display104through several different implementations disclosed herein.

In one implementation, a stationary grating structure-type voxel projector508may be configured to manipulate the light beam510by magnifying and/or projecting the light beam510into a larger area in the volume of the 3D volumetric display104. The stationary grating structure-type voxel projector508may allow small changes in the X and/or Y dimensions by the scanning mirror504to cause larger changes in the X and/or Y dimensions in the volume of the 3D volumetric display104.

In another implementation, a stationary metasurface structure-type voxel projector508may be configured to manipulate the light beam510by magnifying and/or projecting the light beam510into a larger area in the volume of the 3D volumetric display104. The stationary metasurface structure-type voxel projector508may allow small changes in the X and/or Y dimensions by the scanning mirror504to cause larger changes in the X and/or Y dimensions in the volume of the 3D volumetric display104.

In a further implementation, a rotatable diffractive plate-type voxel projector508may be rotated to shift the light beam510in an X dimension within the volume of the 3D volumetric display104. Then the light beam may be adjusted in the Y dimension within the volume by moving the light beam radially on the diffractive plate-type voxel projector. The rotatable diffractive plate-type voxel projector508may allow small changes in the X and/or Y dimensions in the rotational and radial position to cause larger changes in the X and/or Y dimensions in the volume of the 3D volumetric display104.

As illustrated inFIG. 6A, the voxel projector508may be implemented as a grating structure600. The grating structure600may permit the expanded beam512to cover more of the volume of a slice606of a 3D image. For example, the scaling of the image from a smaller planar dimension to a larger planar dimension increases the dimension of the accessible beam region of slice606.

In such an implementation, grating structure600may be used in combination with a liquid crystal602. The role of the grating structure600is to increase the dimension of the accessible beam region of slice606. The role of the liquid crystal302is to choose which pixel should be illuminated. For example, liquid crystal602allows an optical beam portion610to pass through a clear portion620of liquid crystal602. Likewise, liquid crystal602blocks an optical beam portion611from passing through a darkened portion621of liquid crystal602.

In the illustrated implementation, the voxel projector508implemented as the grating structure600may be stationary. Accordingly, orientation changes by the scanning mirror (e.g., seeFIG. 2) may control the relatively larger changes in the X and Y dimension of the expanded beam512that is projected into the volume of the stationary gain medium.

The grating structure600may include a surface structure pattern603. An individual part of the surface structure pattern603may be at a scale larger than a wavelength of the light beam. Such a grating structure600may be a Dammann-type grating, or the like.

As used herein the term “grating” may refer to indents in a plane, where the indents correspond to specific angles of refraction based on wavelength of light incident on the indents (e.g., as individual part of the surface structure pattern603). For example, the indents in such a grating are at a scale larger than the wavelength of light. In some examples, the suitable size of the indents in such a grating may be dependent on the wavelength of light utilized. In an example where the light used has a one micron wavelength, the indents in such a grating may be larger than one micron, and/or a similar size, for example (e.g., an individual surface structure pattern within the grating structure may be at a micron scale of between 1-10 microns). Typically, gratings may provide diffracted of light expansion access mostly limited to an expansion in one dimension, e.g., horizontal or vertical.

In the illustrated implementation, the voxel projector508implemented as the grating structure600may be stationary. Accordingly, orientation changes by the scanning mirror (e.g., seeFIG. 5) may control the relatively larger changes in the X and Y dimension of the expanded beam512that is projected into the volume of the stationary gain medium.

In operation, a plurality of voxel projectors508implemented as grating structures600may be utilized. For example, for red-green-blue-type systems, a single red optical beam may be associated with a first grating structure600, a single blue optical beam may be associated with a second grating structure600, and a single blue optical beam may be associated with a third grating structures600.

As illustrated inFIG. 6B, another illustrative diagram of a stationary grating structure600according to an embodiment the voxel projector508may be implemented to accommodate two optical beams being used in conjunction. For example, two optical beams may be used in conjunction to generate two-photon luminescence to illuminate a given voxel in 3D space. In such an implementation, each pair of optical beams may be associated with a corresponding pair of grating structures600.

For example, a first optical beam510may be associated with a first grating structure600and a second optical beam660may be associated with a second grating structure650. The grating structures600and650may permit the expanded beam512and662to cover more of the volume of a slice606of a 3D image.

In such an implementation, second grating structure650may be used in combination with a second liquid crystal652. The role of the second grating structure650is to increase the dimension of the accessible beam region of slice606. The role of the second liquid crystal652is to choose which pixel should be illuminated. For example, the second liquid crystal652allows an optical beam portion666to pass through a clear portion370of the second liquid crystal652. Likewise, the second liquid crystal652blocks an optical beam portion666from passing through a darkened portion621of the second liquid crystal652. For example, the expanded beams512and662may illuminate voxel pattern680while darkening voxel pattern681.

As illustrated inFIG. 7, the voxel projector508may be implemented as a metasurface structure700. The metasurface structure600may permit the expanded beam to cover more of the volume of a slice of a 3D image.

For example, such a metasurface structure700may include a surface structure pattern703. An individual part of the surface structure pattern703within the metasurface structure700may be at a scale smaller than a wavelength of the light beam.

As used herein the term “metasurface” may refer to microscopic surface structure pattern in a plane, where the microscopic surface structures correspond to specific angles of refraction based on wavelength of light incident on the microscopic surface structures (e.g., as an individual part of the surface structure pattern703). For example, the microscopic surface structures in such a metasurface may be at a scale smaller than the wavelength of light. In some examples, the suitable size of the microscopic surface structures in such a metasurface may be dependent on the wavelength of light utilized. In an example where the light used has a one micron wavelength, the microscopic surface structures in such a metasurface may be at a nanoscale, e.g., smaller than one micron, such as three hundred nanometers, two hundred nanometers, and/or a similar size, for example (e.g., an individual surface structure pattern within the metasurface structure is at a scale of between 100-900 nanometers).

FIG. 7illustrates the relative aspect ratio of the accessible region606in 2D space as compared to the overall 2D space of the metasurface structure700. In the illustrated example, a metasurface of 600 nanometers (e.g., as illustrated at item704) may increases the dimension of the accessible beam region of slice606to 60 microns (e.g., as illustrated at item708). Typically, metasurfaces may provide diffracted of light expansion access to an expansion in two dimensions, e.g., horizontal and vertical, and provide control over the light's phase and amplitude.

Additionally, even though an optical beam may illuminate a small voxel region, the visibly effective pixel size can be larger. For example, the effective pixel size will vary depending on the radiative pattern of the emissive material. For more emissive materials, a given illuminated voxel region may result in a larger visibly effective pixel size, as compared to operations with a less emissive material.

In some implementations, the voxel projector508implemented as the metasurface structure700may be stationary. Accordingly, orientation changes by the scanning mirror (e.g., seeFIG. 5) may control the relatively larger changes in the X and Y dimension of the expanded beam (e.g., seeFIG. 2) that is projected into the volume of the stationary gain medium.

In operation, a plurality of voxel projectors508implemented as metasurface structures700may be utilized. For example, for red-green-blue-type systems, a single red optical beam may be associated with a first metasurface structure700, a single blue optical beam may be associated with a second metasurface structure700, and a single blue optical beam may be associated with a third metasurface structure700.

Alternatively, as discussed above, some systems may utilize pairs of optical beams in conjunction to generate two-photon luminescence to illuminate a given voxel in 3D space. In such an implementation, each pair of optical beams may be associated with a corresponding pair of metasurface structures700.

As illustrated inFIG. 8metasurface structure700may be utilized in a manner similar to grating structure300to generate an image800. In the illustrated example, a liquid crystal back plane802may modify the region of illuminated-interest. In such an implementation, metasurface structure700may be used in combination with liquid crystal back plane802. The role of the metasurface structure700is to increase the dimension of the accessible beam region of a slice of image800. The role of the liquid crystal back plane802is to choose which pixel should be illuminated within image portion804. For example, liquid crystal back plane802allows an optical beam to pass through a clear portion820of liquid crystal back plane802. Likewise, liquid crystal802blocks an optical beam from passing through a darkened portion821of liquid crystal back plane802.

As illustrated inFIG. 9, the voxel projector508may be a rotatable diffractive plate900. For example, a radial location902of the light beam508on the rotatable diffractive plate800and rotational orientation904of the rotatable diffractive plate900may be used to control the relatively larger changes in the X and Y dimension of the expanded beam that is projected into the volume of the stationary gain medium. The rotatable diffractive plate900may permit the expanded beam512to cover more of the volume of a slice906of a 3D image.

In such an implementation, specific locations on the rotatable diffractive plate800will correspond to specific locations on an XY coordinate plane. For example, a series of these specific locations may be oriented as a spiral, or similar functional orientation, on the rotatable diffractive plate900. These specific locations on the rotatable diffractive plate800may be similar to memory on a Compact Disc (CD). Accordingly, the resolution of the coordinate plane may be defined by the specific locations on the rotatable diffractive plate900, e.g., by the “memory” of the disc.

Advantageously, the relatively larger changes in the X and Y dimension of the expanded beam512that is projected into the volume of the stationary gain medium causes changes in the X and Y dimensions of sufficient size to speed up raster scanning of voxels to obtain a resolution of one thousand and twenty-four pixels over a thirty centimeter display area. Similar results may be obtainable from the implementations illustrated inFIGS. 6A-8.

As illustrated inFIG. 10, the lens506may be positioned close enough to the spinnable diffractive plate900to remove any possible angle of photons. In such an implementation, a bracket1000may be coupled to the lens506and scanning mirror504. The bracket1000may be configured to maintain the placement of the lens506with respect to the spinnable diffractive plate900to remove any possible angle of photons.

A first motor1002may be operatively associated with the mirror504and variable focal length lens506. For example, the first motor1002may be attached to the mirror504and variable focal length lens506via the bracket1000to control the placement of the lens506with respect to the spinnable diffractive plate600.

A second motor1004may be operatively associated with the spinnable diffractive plate600. The second motor1004may control the spin of the spinnable diffractive plate900.

A third motor1006may be operatively associated with the spinnable diffractive plate600. The second motor1004may control movement the linear movement of the spinnable diffractive plate900.

As with some of the other implementations described herein, a plurality of the voxel projectors508with rotatable diffractive plates900could be used at the same time in a single 3D volumetric display.