Abstract:
A system and method for creating a three-dimensional (“3D”) volumetric display using a linear array of active point light sources and projecting those points on a mirrored surface. The linear image is then modulated and swept along that mirrored surface to create a two-dimensional (“2D”) raster image. Simultaneously, the mirrored surface upon which the raster image is created is rotated along a axis that is orthogonal to the raster image. During the orthogonal rotation the 2D raster image is redrawn as separate frames in a timed and coordinated manner such that each pixel element (“pixel”) of the 2D image is displayed sequentially in 3D space as a volumetric pixel element (“voxel”). The integrating characteristics of human sight are then used to create the impression of a volumetric surface from the integration of the raster images.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This non-provisional United States (U.S.) patent application claims the benefit of 35 U.S.C. §119 and Provisional Patent Application No. 60/983,861 entitled filed on Oct. 30, 2007, which is hereby expressly incorporated by reference herein. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates to the field of electrical image creation and display. More specifically, the invention relates to the technical field of three-dimensional translation and volumetric display. 
       BACKGROUND OF THE INVENTION 
       [0003]    In recent years people have adjusted to viewing representations of the real world through images and text on a two-dimensional screen. Technology continues to develop at lightening speed in order to better generate this fictitious two-dimensional world. Although the mechanics of a two-dimensional screen are simpler, it is well known that a three-dimensional display can be more accurate, more pleasing to the eye, more recognized by the human brain and provide a myriad of options that are not possible with traditional screens. Therefore, it is one object of the present disclosure to provide for a system that facilitates display of a three-dimensional image. 
       SUMMARY OF THE INVENTION 
       [0004]    A system and method for creating a three-dimensional (“3D”) volumetric display using a linear array of active point light sources and projecting those points on a mirrored surface. The linear image is then modulated and swept along that mirrored surface to create a two-dimensional (“2D”) raster image. Simultaneously, the mirrored surface upon which the raster image is created is rotated along an axis that is orthogonal to the raster image. During this orthogonal rotation the 2D raster image is redrawn as separate frames in a timed and coordinated manner such that each pixel element (“pixel”) of the 2D image is displayed sequentially in 3D space as a volumetric pixel element (“voxel”). The integrating characteristics of human sight are then used to create the impression of a volumetric surface from the integration of the raster images. 
         [0005]    These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiments that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrated and not to limit the invention, wherein like designations denote like elements, and in which: 
           [0007]      FIG. 1  is a side view, in accordance with an embodiment of the present invention. 
           [0008]      FIG. 2  is a top angled view of the embodiment shown in  FIG. 1 . 
           [0009]      FIG. 3  is a magnified view of the mirrored frame and LED array of the embodiment shown in  FIGS. 1 and 2 . 
           [0010]      FIG. 4  is a schematic for the deflection device operating against the mirror, in accordance with an embodiment of the present invention. 
           [0011]      FIG. 5  is a raster image that forms on the mirror, in accordance with an embodiment of the present invention. 
           [0012]      FIG. 6  illustrates the formation of frames through the rotation of the mirror, in accordance with an embodiment of the present invention. 
           [0013]      FIG. 7  illustrates the translation of pixels into a 3D image in Cartesian coordinates, in accordance with an embodiment of the present invention. 
           [0014]      FIG. 8  illustrates a simplified architecture for the drive electronics of the embodiment shown in  FIG. 1 . 
           [0015]      FIG. 9  illustrates an alternate embodiment of the present invention. 
           [0016]      FIG. 10  illustrates rotation of a mirrored frame about X and Y axis, in accordance with the embodiment of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    In the following detailed description of the various embodiments of the invention, reference is made to the accompanying drawings which form a part of thereof and in which is shown by way of illustration various embodiments in which invention may be practiced. Numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it will be obvious to one skilled in the art that the embodiments of the invention may be practiced without these specific details. In other instances well known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments of the invention. 
         [0018]    Furthermore, it will be clear that the invention is not limited to theses embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without parting from the spirit and scope of the invention. 
       Mechanics 
       [0019]      FIG. 1  is a side view, in accordance with an embodiment of the present invention.  FIG. 1  shows the preferred embodiment of the invention. A double sided mirror  20  is finished to provide a diffusely reflective surface. The mirror spins around its vertical axis being secured by bearings  22  and  24 . A mirror assembly shaft  26  rotates within the bottom bearing. The top bearing is secured to the housing (not shown for clarity). The shaft is electrically connected to main circuit board  28  by way of commutators  30 . 
         [0020]      FIG. 3  is a magnified view of the mirrored frame and LED array of the embodiment shown in  FIGS. 1 and 2 . The shaft is electrically connected to a linear LED array  32  and another array on the opposite side of a mirror frame  34  as shown in  FIG. 3 . The mirror frame is bonded with the main gear and shaft to form a single unit that uses a counter weight  34 B for rotational balance. A motor  33  spins the mirror and the rest of its assembly by driving assembly gear  36  via motor gear  38  that is connected to the motor&#39;s shaft. The assembly gear is secured to the motor assembly shaft to the transfer motion. When the mirror assembly is spun about its axis image deflection devices  40 A and  40 B shown in  FIGS. 1 and 2  are rotated by a gearbox  42 . The gearbox works against a stationary frame  44  that also secures the motor, bottom bearing and main circuit board. The top of this frame is a gear track that drives the gearbox and hence the deflection devices when the top assembly is rotated with respect to it. For timing an optical sensor  46  senses the crossing of the mirror assembly at a consistent point for each revolution of the main mirror assembly. The trip for the sensor is a tab molded into the main gear assembly driving the mirror assembly. 
         [0021]    Alternate embodiments for drive and connection of the main board  28  and LED arrays  32  and  34  include using commutators for power on, and transmitting data to the LED board wirelessly using either radio frequency such as wireless USB or through an optical connection. Additionally, even the commutator connections for power can be eliminated by wirelessly transmitting power to the LED arrays using inductive conduction. The mechanical gear connection can be eliminated by using other pulley or chain mechanisms. It can also be accomplished by using magnetic coupling. This coupling can use permanent magnets an electromagnet including a stator-armature method or other coupling methods known in the art. Additionally, the double sided mirror can also be replaced by a single sided one. The deflection devices can also be driven by a separate motor or motors that would revolve with the mirror assembly. 
         [0022]      FIG. 4  is a schematic for the deflection device operating against the mirror, in accordance with an embodiment of the present invention.  FIG. 4  shows a schematic for the deflection device  40 A operating against the mirror. As the deflection device rotates a linear pattern is multiplexed on the LED array  32  comprised of a line of LEDs  48 . The LEDs have lenses that focus their light on the deflection device. The deflection device in this embodiment is optionally smooth. Rays cast from the LED array  50  are incident on the deflection device. As it is rotated the incident ray is reflected onto the mirror. Ray  52  is reflected as a sharp angle and is focused on the bottom of the mirror. As the deflection device is further rotated ray  54  is formed and focused further toward the top of the mirror. 
         [0023]    Alternate embodiments for the deflection device  40 A include curved surface on the device to compensate for differences in focus of the reflected beam. Also, more or fewer surfaces can be used including a single sided flat mirror geometries having numbers of surfaces greater than a hexagon. 
         [0024]      FIG. 5  is a raster image that forms on the mirror, in accordance with an embodiment of the present invention.  FIG. 5  shows a raster image that is formed on the surface of the mirror. The linear LED arrays cast an entire row across the mirror. Each pixel  56 , on this image is scanned by the deflection device in a vertical manner to complete an entire 2-dimensional image. While each image is displayed, the mirror rotates partially, through its path of 360 degrees. 
         [0025]      FIG. 6  illustrates the formation of frames through the rotation of the mirror, in accordance with an embodiment of the present invention. Within a fraction of the rotation θ m  one frame is finished and another is started as shown in  FIG. 6 . 
         [0026]      FIG. 7  illustrates the translation of pixels into a 3D image in Cartesian coordinates, in accordance with an embodiment of the present invention. Pixels  58 A and  58 B get translated into a 3-dimensional presence. The mirror rotates through the Z-X axis and the deflection device produces the Y-axis offset. 
         [0027]      FIG. 8  shows a simplified architecture for the drive electronics in accordance with an embodiment of the present invention. External human interfaces  60  such as power or battery input, switch input, sensor input, audio data and USB connections are connected respectively to the main board power supply  62  and the system on silicon (“SOS”)  64 . Outputs from both of these are then connected by a power transfer means  66  and data link means  68  to the LED array that spins on the mirror assembly with the mirror. The data link  68  transfers image and control data to the LED arrays. Data link method  70  transfers both power and data between the main board and LED arrays. The motor is controlled by the system on silicon by means of a driver  72 . This driver controls speed and startup of the motor. On the LED arrays a power receiving means  74  receives the transmitted power required to drive the arrays and controls and distributes that power using array power supply  76 . A data connection means  78  routes data and commands through MCU  80  and its resources including image buffer memory  82 . The MCU drives the LED array using an array of drives  84 . Each LED in the array is driven individually. Only one driver and LED are shown for clarity. 
         [0028]      FIG. 9  shows an alternate embodiment for the invention. It is substantially the same with the exception of the following noted features.  FIG. 10  illustrates rotation of a mirrored frame about X and Y axis, in accordance with the embodiment of  FIG. 9 . The mirror in this embodiment is held by frames  84 A and  84 B in a gimbaled frame  86  that rotates about the Y-axis as shown in  FIG. 10 . Simultaneously, the mirror is rotated in the orthogonal X-axis as also shown in  FIG. 10  by a gearbox  88  that acts against system&#39;s stationary frame. This orthogonal rotation causes the linear array of LEDs  90  located on the LED array circuit board  92  to create a raster image on the mirror equivalent to  FIG. 5 . Then when rotated in the Y-axis image frames are translated into a volume display in an equivalent transform to that shown in  FIG. 7 . 
       Operation 
       [0029]    This invention relies on the integration and depth perception characteristics of natural human sight to provide the perception of a 3D object in a defined space. In the preferred embodiment a volume display is generated by use of the deflection devices  40 A and  40 B to create a raster image made of individual pixels  56  combined in 2D matrix as shown in  FIG. 5 . There are two such deflection devices because the mirror is double sided; there is one on each side. The deflection devices are held orthogonally with respect to each of the mirrors on which they project by the frame section  34  and its associated components bonded to it including the counter weight  34 B, the main gear  36 , the bottom commutator shaft  26  and the main mirror  20  that is bonded in the slot between two the deflection devices in  FIG. 3 . The gears at one end of the deflection devices shown directly drive the axial shafts on their respective deflection devices. These gears maintain a fixed relative rotational position with respect to each other and their drive at all times. The counter weight provides balance to reduce vibration when the frame and its bonded components are spun. Although not necessary a double sided mirror  20  is preferred over a single sided one as that will cut in half the number of rotations about the Y-axis required to display a volume. 
         [0030]    In this preferred embodiment the frame  44  remains stationary with respect to the rotating mirror assembly. The frame also holds the motor  33 , bottom bearing  24  and main PCB  28 , stationary with respect to the mirror assembly. In a final product configuration, this frame would also be made stationary with respect to the product housing or its features may be made as an integral part of the housing. The bearing shaft  22  would also be accommodated with a receptacle in the product housing to help stabilized the mirror assembly when rotating. The motor supplies the force to drive the Y-axis rotation as it is coupled by the motor shaft gear  38  to the main assembly gear  36 . Using the gear teeth on the frame, the gearbox  42  translates the mirror assembly&#39;s motion into rotation of the deflection devices orthogonal to the mirrors. The speed of this rotation depends on the number of voxels that need to be displayed in 3D. For illustration, if the LED array is comprised of 96 LEDs in the X-axis and the 2D raster image is square in the Y-axis, the 2D image would be a 96 by 96 pixel raster image. In this case  FIG. 5  would have a linear image created by 96 point sources and there would be 96 rows multiplexed onto the mirror by each deflection device projecting on its respective mirror. When the mirror assembly is driven by the motor, it spins on the Y-axis as shown in  FIG. 6 . A complete 2D image is formed within the angular displacement θ m  translating this into 3D space according to the Cartesian transform in  FIG. 7 . In  FIG. 7 , only two voxels  58 A and  58 B are shown. In an actual image, naturally, a full surface would be defined by a large number of voxels. The number of voxels is determined by the rotational speed of the deflection device surface with respect to the speed of the mirror assembly&#39;s rotation. Using a dual mirror producing 15 images per second, a net 7.5 revolutions per second of the mirror assembly is required. 15 images per second is at the threshold speed of where visual integration will begin to be lost, causing flickering, if any slower rate is used. If voxels are to be able to be displayed in space at 96 angular displacements per 360° of viewing angle in the Y-axis then the displacement devices must rotate at (7.5 rps *96 fpr )/N dd , where N dd  is the number of reflective surfaces presented by the deflection device in one of its rotations of 360°, 7.5 rps  is the example angular velocity in revolutions per second of the main mirror assembly and 96 fpr  is the number of 2D image frames per revolution per one revolution of the main mirror. For reference at 96 fpr, θ m =360°/96 or 3.75°. Schematically,  FIG. 4  shows this for one side of the mirror assembly. The reflective surface of the deflection device is specular to provide a narrow focus onto the main mirror. The main mirror is diffusely reflective to help improve the viewing angle for the user. A pentagonal structure is used for illustration of the deflection device. Hence, 5 raster images are projected on the main mirror for each complete revolution of the deflection device. The actual mechanical rotation for each deflection device is provided by gearbox  42 . Based on a pentagonal deflection device and 96 2D images per revolution of the main mirror, the required gearing ratio for this example would be 96/5:1. Any number of deflection devices surfaces per rotation form one surface to more than 10 is feasible. The LED array  32  is comprised, for this embodiment, of a line of 96 LEDs  48 . The LED lenses and the surfaces of the deflection device are optimized to provide proper focus on the main mirror after reflection off the respective deflection device. Through each rotation of the pentagon, 5 surfaces are presented for reflection. The incident rays are projected onto the presented surface of the deflection device along the projected path  50 . Depending on the angular position of the reflecting surface of the deflection device, the incident ray is deflected based on the taws of reflection onto the main mirror. Based on the angular direction shown, the ray  52  is projected on the portion of the main mirror that is closest to the respective deflection device. After the deflection device has rotated along the angular axis shown the ray  54  is deflected towards the opposite end of the main mirror. Deflection devices do not have to be rotating to create the deflection angle. They can be any other of variable reflective or refractive surface that is timed with the rotation of the main mirror assembly. This includes solid stated devices driven by piezoelectric, other acoustic wave devices or electromagnetic drives such as a linear motor or voice coil θ pixel reflection using a rotating deflection device will have a constant velocity across the main mirror. An oscillating deflection will have a varying velocity depending on the driving waveform. In most cases, this would be a sinusoid or portion thereof. Thus changes in velocity would need to be compensated either through a non planar surface on the deflection device&#39;s reflecting surface or by varying the duration of projection of each row of pixels in each frame. Additionally, the deflection device can be driven by an independent drive such as another motor or oscillating driver. Since the gear driven mechanism of the deflection devices in this embodiment is deterministic with respect to the main mirror&#39;s rotational displacement only one timing reference measured by optical sensor  46  needs to be used. The reference is derived from passing a tab that is secured to the main assembly gear through an optical sensor  46 . In the case where an unsynchronized deflection device drive is used, a separate timing reference that is relative to the deflection device&#39;s position with respect to the main mirror would be needed. 
         [0031]    The shaft  26  of the drive mechanism also provides a mechanism for this embodiment to establish communication between the main PCB and the LED array via the 3-contact isolated commutator  30 . The LED array  32  is comprised of a PCB itself onto which the LEDs are mounted. As shown in  FIG. 8  both boards are controlled by complex logical functions. On the LED array, a microcontroller unit  80  interacts with a SOS device  64  to establish a reliable communication channel for transfer of voxel data from the main board to the LED array. This data is transferred in simple compressed format such as run length limited format to reduce bandwidth and ensure bit recovery. Because of the inherent noise of commutators error checking and retransmit are facilitated over the single data contact referenced to power ground as well. Alternate communication methods such as cortical linkage or RF linkage can be used and would require the data link comprised of link  68  on the main board and  78  on the LED array to be changed accordingly. Two of the three commutators would transfer power and common ground according using link  66  on the main board and  74  on the LED array. Because of the inherent noise in such mechanical connections the power supply on each side of the system link  70  would need appropriate filtering to insure a delivery of a stable form to the resources on each board. The power supply  62  would be under control of the main system on silicon and would support power management to save energy. The power support  76  on the LED array would be a slave to this supply. Other methods such as inductive coupling can be used but would require a more sophisticated, smart power supply arrangement on both sides of the link. Regardless of the embodiment, the system link  70  passing both power and data is established using connections that support the independent rotation of the LED assemblies that are attached to the mirror and deflection device frame. The system on silicon has an internal processor and memory that not only facilitates the communication link with the LED array but also performs system functions including power control via the power supply  62  and user interface via user interfaces  60  as required by the user application. For example, not only could simple displays be created, higher level functions such as gaming and communication with other devices can be facilitated. The motor  33  is controlled by a simple power driver  72 . Because of the timing reference provided by the gear position sensor  46  proportional control of the motor is required. To facilitate reliable communications between the LED array and main board, the buffer memory  82  is used to preload images and decompress images at a rate faster than the display of those images. This allows overhead for retransmissions and for synchronization with the position sensors trigger point. The LED array  32  is modulated by an array of drivers  84 . Each LED in the array is driven by an independent driver. In this embodiment the display is monochrome. Brightness is adjusted by pulse width modulation of the drive waveform by the driver under control of the MCU. An alternate embodiment could use a simple on or off switch if grayscale is not needed. Conversely, if color was required separate channels per pixel made up of red, green and blue LEDs could be driven with independent pulse width driver to form a full color raster image. 
         [0032]      FIG. 9  and  FIG. 10  show an alternate system embodiment that does not use deflection devices. Other than the features enumerated in  FIG. 9  and illustrated in  FIG. 10 , the system is the same as the latter. In place of the deflection devices, the 2D raster image projected on each side of the main mirror is created by rotating the entire mirror through 360° in the X-axis with respect to a single row of LEDs  90  that are mounted on the PCB  92 . The PCB is rotated with respect to the Y-axis and is fixed in a parallel orientation with respect to the axis of rotation of the main mirror. The mirror frame is comprised of two segments  84 A and  84 B that are bonded to opposite edges of the mirror. These segments have two shafts that allow rotation of the mirror in the θ frame  86 . The frame is fixed to the PCB. The gearbox  88  rotates the mirror by driving it in the same manner as the deflection device in the preferred embodiment. Based on the 3D display resolution, the gearbox ratio would need to be changed. For the 96x, 96y per 3.75° of rotation at 15 fps  the mirror would need to be rotated in its X-axis 96 time per Y-axis revolution. Because of the double sided mirror the angular velocity would be 7.5 revolutions per second in the Y-axis. 
         [0033]    The present invention includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention those skilled in the art will appreciate that there are numerous variations and permutations of the above described apparatus and techniques. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims. 
         [0034]    While the principles of the disclosure have been illustrated in relation to the exemplary embodiments shown herein, the principles of the disclosure are not limited thereto and include any modification, variation or permutation thereof.