Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
  • G02B3/0006—Arrays
  • G02B3/0037—Arrays characterized by the distribution or form of lenses
  • G02B3/0056—Arrays characterized by the distribution or form of lenses arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
  • G02B26/0875—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more refracting elements
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
  • G02B3/0006—Arrays
  • G02B3/0037—Arrays characterized by the distribution or form of lenses
  • G02B3/0062—Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
  • G02B3/0006—Arrays
  • G02B3/0037—Arrays characterized by the distribution or form of lenses
  • G02B3/0062—Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
  • G02B3/0068—Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
  • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
  • G02B30/26—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type
  • G02B30/33—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type involving directional light or back-light sources
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/30—Image reproducers
  • H04N13/302—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays
  • H04N13/307—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays using fly-eye lenses, e.g. arrangements of circular lenses
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/30—Image reproducers
  • H04N13/302—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays
  • H04N13/32—Image reproducers for viewing without the aid of special glasses, i.e. using autostereoscopic displays using arrays of controllable light sources; using moving apertures or moving light sources
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/30—Image reproducers
  • H04N13/356—Image reproducers having separate monoscopic and stereoscopic modes
  • H04N13/359—Switching between monoscopic and stereoscopic modes

Definitions

• the present invention relates to the field of directional light modulation, 3D displays, emissive micro displays, 2D/3D switchable displays and 2D/3D
• 3D displays In 3D displays, directional modulation of the emitted light is necessary to create the 3D viewing perception.
• a backlight with uniform illumination in multiple illumination directions is required to display images of the same scene from different directions by utilizing some combination of spatial multiplexing and temporal multiplexing in the spatial light modulator.
• the light that typically comes from the directional backlight is usually processed by a directionally selective filter (such as a diffractive plate or a holographic optical plate for example) before it reaches the spatial light modulator pixels that modulate the light color and intensity while keeping its directionality
• a directional backlight is necessary to operate the display in different display modes.
• a backlight with uniform illumination and large angular coverage is required to display a single image with spatial light modulators (such as liquid crystal displays (LCD)).
• a backlight with uniform illumination and multiple illumination directions is required to display images of the same scene from different directions by utilizing some combination of spatial multiplexing and temporal multiplexing in the spatial light modulator.
• the light that comes from the directional backlight is usually processed by a directionally selective filter (such as diffractive plate, a holographic optical plate etc.) before it reaches the spatial light modulator pixels to expand the light beam uniformly while keeping its directionality.
• a directionally selective filter such as diffractive plate, a holographic optical plate etc.
• an illumination unit comprising multiple light sources and a directional modulation unit that directs the light emitted from the light sources to a designated direction (see Figures 1 , 2 and 3).
• an illumination unit is usually combined with an electromechanical movement device such as scanning mirrors or rotating barriers (see U.S. Patent Nos. 6,151 ,167, 6,433,907, 6,795,221 , 6,803,561 , 6,924,476,
• the prior art directional backlight units need to have narrow spectral bandwidth, high collimation and individual controllability for being combined with a directionally selective filter for 3D display purposes.
• Achieving narrow spectral bandwidth and high collimation requires device level innovations and optical light conditioning, increasing the cost and the volumetric aspects of the overall display system.
• Achieving individual controllability requires additional circuitry and multiple light sources increasing the system complexity, bulk and cost.
• Figure 1 illustrates a prior art directional light modulator that uses liquid lens.
• Figure 2 illustrates a prior art directional light modulator that uses scanning mirrors.
• Figure 3 illustrates a prior art prior direction ally modulated 3D light
• Figure 4 illustrates the spatio-optical directional light modulation aspects of the temporal spatio-optical directional light modulator.
• Figure 5 is an isometric view of the directional light modulation principle of the spatio-optical directional light modulator.
• Figure 7 illustrates an exemplary design of the spatio-optical directional light modulator that uses wafer level optics exemplary design illustrated in Figure 6.
• Figure 9 illustrates an exemplary embodiment of directional modulation within one of the spatial modulation pixel groups of the temporal spatio-optical directional light modulator.
• Figure 10 is a block diagram explaining the data processing block diagram of the spatio-optical directional light modulator.
• Figure 1 1 illustrates an isometric view of an exemplary embodiment of a 3D/2D switchable display implemented by tiling a multiplicity of the spatio-optical directional light modulators.
• Figure 12 illustrates an isometric view of the principle aspects of the temporal spatio-optical directional light modulator.
• Figure 13A illustrates the angular emission expansion made possible by the temporal articulation aspects of the temporal spatio-optical directional light modulator.
• Figure 13B illustrates the angular temporal articulation of the temporal spatio-optical directional light modulator.
• Figure 14 illustrates the extended angular coverage cross section of the temporal spatio-optical directional light modulator.
• Figure 15 illustrates isometric, side and top views of one embodiment of the temporal spatio-optical directional light modulator.
• Figure 16 illustrates isometric, side and top views of another embodiment of the temporal spatio-optical directional light modulator.
• the solid state light emitting pixels of one such a device may be either a light emitting diode (LED) or laser diode (LD) whose on-off state is controlled by the drive circuitry contained within a CMOS chip (or device) upon which an emissive micro-scale pixel array is bonded.
• the size of the pixels comprising the emissive array of such devices would typically be in the range of approximately 5-20 micron with the typical emissive surface area of the device being in the range of approximately 15-150 square millimeter.
• the pixels within the emissive micro-scale pixel array device are individually addressable spatially, chromatically and temporally, typically through the drive circuitry of its CMOS chip.
• QPI devices see U.S. Patent Nos.
• the present invention combines the emissive micro pixel array capabilities of the QPI device with passive wafer level optics (WLO) alone or with an articulated movement of the entire assembly to create a light modulator that can perform the functionalities of a directional light source and a diffractive plate of the prior art at the same time.
• WLO wafer level optics
• wafer level or wafer means a device or matrix of devices having a diameter of at least 2 inches, and more preferably 4 inches or more.
• WLO are fabricated monolithically on the wafer from a polymer using ultra violet (UV) imprint lithography.
• WLO small feature micro lens arrays
• MLA small feature micro lens arrays
• QPI optoelectronics device
• directional modulation of the emitted light is achieved by the light divergence achieved by the WLO, and in other embodiments is achieved by the combination of the light divergence achieved by the WLO and the articulated movement of the entire assembly.
• each of the micro lens elements 400 comprising the 2-dimensional micro lens array MLA 220 is the group of individually addressable QPI pixels (p 1 , p 2 , - , p n ) whereby the light emitted from each of the pixels in this group of pixels would be refracted into one of the unique directions (d l t d 2 ,..., d n ) within the numerical aperture (angular extent) of their associated micro lens element.
• the entire micro-pixel array of the QPI device 21 0 would comprise a multiplicity of QPI pixel groups (G 1; G 2 ,...,G N ), herein also referred to as pixel modulation groups, whereby each modulation group G t would be associated with one of the 2-dimensional array MLA 220 lens elements and collectively the pixel modulation groups (G 1 , G 2 ,...,G N ) would then represents the spatial modulation array of the spatio-optical directional light modulators of this invention.
• i 1,2, representing the multiplicity of light modulation directions individually addressable through temporal addressability of the pixels (pi, p 2 , - , p n ) of the QPI device 21 0 comprising each pixel modulation group.
• the temporal spatio-optical directional light modulators illustrated in Figure 1 2 would be able to generate light that can be spatially and directionally modulated whereby the light emitted from each of the spatial locations that equals the emissive area of the QPI pixel groups (G 1 , G 2 ,...,G W ) is individually addressable through the addressability of the pixel groups as well as being directionally addressable through the temporal
• Figure 5 illustrates the spatial and directional modulation principles of the present invention.
• Figure 5 illustrates a 2-dimensional array comprising a
• the individual pixels of the QPI device can be modulated so that each lens in the MLA can emit light to multiple directions simultaneously. Because of individual pixel control, the light amplitude, the time duration of the light emission, the specific light direction and the total number of light directions emitted from each micro lens can be individually adjusted through the individual addressability of the QPI device pixels.
• the directional modulation by a lens can be done on a single axis, or on two axes with the choice of lens type (i.e., lenticular lens array or two-axis lens array).
• lens type i.e., lenticular lens array or two-axis lens array.
• precise alignment of the lens array with the pixelated light source and the achievability of small pixel size have prevented the realization of a directional light modulator that can generate the directional light modulation capabilities needed to create high definition 3D displays.
• the high pixel resolution is achieved by leveraging the emissive micro pixel array of the QPI device, which can attain less than 10 micron pixel pitch, and the high precision alignment of lens array, which can be less than one micron, made possible by the wafer level optics.
• This allows the spatio-optical light modulator to achieve the spatial as well as directional modulation resolution sufficient to realize high definition 3D displays.
• Figures 6 and 7 show an exemplary embodiment of the present invention.
• the light emitted from each individual pixel within a pixel group G travels from the QPI device emissive surface to the exit aperture of a micro lens that comprises the three optical elements 610, 620 and 630.
• a multiplicity of the optical elements 610, 620 and 630 are fabricated to form micro lens array layers 710, 720 and 730 which would be precisely aligned relative to each other and relative to the associated arrays of the QPI device pixel groups Gi , G 2 ,..., GN-
• the exemplary embodiment illustrated in Figure 7 also includes the QPI device 210 and its associated QPI device cover glass 760.
• the design of the optical elements 610, 620 and 630 would take into account the thickness and optical characteristics of the QPI device cover glass 760 in order to image the emissive surface of the QPI device cover glass 760.
• the exemplary embodiment of Figure 7 illustrates the full assembly of the spatio-optical directional light
• the typical total thickness of this exemplary embodiment of the spatio- optical directional light modulators of this invention illustrated in Figure 7 would be less than 5 millimeters. Such compactness of the directional light modulator is not possibly achievable by directional light modulation techniques of the prior art.
• Figure 8 and Figure 9 illustrate the operational principles of the spatio-optical directional light modulator.
• the directional modulation addressability that can be achieved by the pixel group G, would be accomplished through the addressability of the pixels comprising the modulation group G, along each of its two axes x and y using m-bit words.
• Figure 9 illustrates the mapping of the light emitted from (nxn) pixels comprising the QPI device pixel group G, into individual directions within the three dimensional volume defined by angular divergence ⁇ of the associated WLO micro lens such as that of the exemplary embodiment 600.
• the resolution of the directional modulation of the light modulators in terms of the number of individually addressable directions within the angular divergence ⁇ of the wafer level micro lens array would be determined by selecting either the pixel pitch of the emissive micro emitter array QPI device or by selecting lens pitch of the wafer level micro lens array, or a combination of the two. It is obvious to a person skilled in the art that the lens system, such as that illustrated in Figure 6, can be designed to allow either wider or narrower angular divergence ⁇ . It is also obvious to a person skilled in the art that either a smaller or a larger number of pixels within each modulation group G, to generate any desired directional modulation resolution.
• such a spatio- optical directional light modulator can be implemented using a tiled array
• each such QPI device can be used to implement an array of (2x2) modulation groups G, and the spatio-optical directional light modulator having (6x6) spatial light modulation resolution and 65,536 directional light modulation resolution would be implemented using a tiled array (3x3) of such QPI devices such as in the illustration of Figure 1 1 .
• the tiling of an array of QPI devices to implement the spatio-optical directional light modulator is made possible because of the compactness that can be achieved by the emissive QPI devices and the associated WLO.
• a QPI device/WLO assembly such as that illustrated in Figure 7 with width, height and thickness of 5.12x5.12x5 millimeters; respectively, to realize the (2x2) modulation group spatio-optical directional light modulator of the previous example. It would also be possible to implement such a QPI device/WLO
• FIG. 1 1 is an illustration of the tiling of multiplicity of the QPI device/WLO assemblies to implement an arbitrary size of the spatio-optical directional light modulators.
• Figure 8 illustrates the two dimensional addressability of each of the modulation groups G, using m-bit resolution for the directional modulation.
• light emitted from (2 m x 2 m ) individual pixels in an n x n array of the modulation group G is mapped by its associated WLO elements into 2 2m light directions within the angular divergence ⁇ of the associated WLO micro lens.
• the spatial resolution of the spatio-optical directional light modulator is simply defined by the coordinates of each of the individual modulation group G, within the two dimensional array of modulation groups comprising the overall spatio-optical directional light modulator.
• Some cross talk between pixels of one group and the micro lens for an adjacent group is substantially reduced by the following design aspects.
• the light emitted from the QPI device pixels is typically confined to a ⁇ 17° cone for the case when the QPI device pixels are light emitting diode or to a ⁇ 5° cone for the case when the QPI device pixels are laser diodes .
• WLO wafer level optics
• the QPI device pixels are laser diodes, the required number of turned off pixels will be even less and may be not even required since in this case the QPI device pixel light emission is confined to an even much narrower ⁇ 5 ° cone. The end result may be some (a few) inactive, blank or dead pixel positions between active pixels in the QPI devices in the array.
• baffles and/or band-limiting light diffusers could be used if desired, though they tend to complicate the design of the light modulator and cause excessive loss of light.
• Figure 1 0 illustrates an exemplary embodiment of the data processing block diagram of the spatio-optical directional light modulators of this invention.
• the input data to the spatio-optical directional light modulator will be formatted in multiple bit words whereby each input word contains the three data fields; one field being the address of modulation group G t within the modulation group array comprising the spatio-optical directional light modulator while the remaining two data fields provide the data representation of the light to be emitted from that modulation group in terms of its color, intensity and direction.
• the data processing block 1 20 decodes the modulation group address field of the input data and route the light modulation data fields to the QPI device associated with the designated modulation group.
• the data processing block 1 30 decodes the routed modulation group address field and maps it to the address of the designated modulation group.
• the data processing block 140 decodes the directional modulation data field and maps it into the address of designated pixel address within the modulation group.
• the data processing block 1 50 concatenates the resultant pixel address with the associated light intensity and color data fields of the input data.
• the data processing block 1 60 decodes the designated pixel address and routes the light modulation data to the designated pixel within the designated QPI device comprising the spatio-optical directional light modulator.
• modulation group would be 40-bit.
• block 120 of Figure 10 would be responsible for routing the sequentially inputted data word to the designated QPI device.
• Block 130 of Figure 10 would be responsible for routing the modulation data to the designated modulation group.
• Block 140 of Figure 10 would be responsible for mapping the 16-bit directional modulation data field into the designated address of the pixel with the designated modulation group.
• Block 150 of Figure 10 would be responsible for concatenating the 24-bit light intensity and color data with the mapped pixel group address.
• Block 160 of Figure 10 would be responsible for routing the 24-bit light intensity and color modulation data to the designated pixel within the designated QPI device
• the spatio-optical directional light modulators would modulate the light emitted from its aperture in intensity, color and direction based on the information encoded within its input data.
• the light intensity and color modulation may be, by way of example, pulse width modulation of the on/off times of the multi color pixels to control the average intensity of the light and to control the intensity of each color component making up the resulting color, though other control techniques may be used if desired.
• the direction and intensity are controlled, and color, direction and intensity are controlled in a multi color system.
• the spatio-optical directional light modulators of this invention can be used as a backlight for liquid crystal display (LCD) to implement a 3D display.
• the spatio-optical directional light modulator by itself can be used to implement a 3D display of an arbitrary size that is realized, for example, as a tiled array of multiplicity of QPI devices/WLO assemblies such as that illustrated in Figure 1 1 .
• the light modulators can also be operated as a 2D high resolution display.
• the individual pixels of the QPI device would be used to modulate the color and intensity while its integrated WLO would be used to fill the viewing angle of the display
• the light modulators it is also possible for the light modulators to be switched from 2D to 3D display modes by adapting the format of its input data to be commensurate with the desired operational mode.
• the light modulators When the light modulators are used as a 2D display, its light angular divergence will be that associated with its WLO micro lens array ⁇ and the pixel resolution of the individual modulation group G, will be leveraged to achieve higher spatial resolution.
• Figure 12 conceptually illustrates another embodiment, a temporal spatio- optical directional light modulator.
• the directional light modulators are comprised of an emissive micro array QPI device 210 with a WLO micro lens array (MLA) 220 mounted directly on top of its emissive surface with the entire assembly being temporally articulated around at least one axis, and preferably around both its x and y axes by angles within the range of ⁇ a x and ⁇ a y ; respectively.
• MLA micro lens array
• the articulation of the QPI/ MLA assembly 230 as illustrated in Figure 12 would be accomplished by placing the entire assembly on a 2-axis gimbal whereby the x-axis of the gimbal is temporally actuated by an angle within the range of ⁇ a x and the y-axis of the gimbal is temporally actuated by an angle within the range of ⁇ a y .
• FIG. 13A shows the temporal expansion of the QPI/MLA assembly 230 angular emission extent along one articulation axis, for the purpose of illustration.
• the angle ⁇ represents the angular extent of one lens element of the MLA 220 and the angle a represents the composite instantaneous articulation angle of the lens element as a result of the gimbal articulation by the angles a x (t and a y (t around the x-axis and the y-axis;
• temporal articulation of the temporal spatio-optical directional light modulator 200 would temporally increase the modulated number of light directions (d l t d 2 ,..., d n ) by the ratio of the angular extent expansion in each articulation direction expressed as ( ⁇ + ⁇ 1 ⁇ 2)(0 + ⁇ ⁇ )/ ⁇ 2 .
• the temporal articulation of the QPI/MLA assembly 230 of the temporal spatio-optical directional light modulators would typically be a repetitive (or periodic) and independent around each of the 2-axis.
• the repetition periods of the articulation of the temporal spatio-optical light modulators would typically be proportional to and synchronized with display input data frame duration (for the purpose of reference, the image input data to a typical display arrives at 60 frames per second and is often referred to as 60Hz frame rate input).
• the maximum values ⁇ xmax of the temporal articulation illustrated in Figures 13A and 13B would determine the expanded angular extent provided by the temporal spatio-optical light modulator which is determined by the value ⁇ (0 + max ), where the angle ⁇ represents the angular extent of the lens elements of the MLA 220.
• the periodicity of the x-axis and y-axis articulation collectively would typically be selected to enable temporal coverage of the desired expanded angular extent of the temporal spatio-optical directional light modulators 200 within a required display input frame rate.
• Figures 12, 13 and 14 illustrate the angular coverage cross section 510 of the QPI/MLA assembly 230 of the temporal spatio-optical directional light modulators 200 being comprised of a multiplicity of the temporally angular coverage cross section 520 of the MLA lens element.
• Appropriately selected temporal articulation a x (t and a y (t of the QPI/MLA assembly 230 around its x-axis and y- axis; respectively, will generate the angular coverage that is comprised of multiplicity of temporally multiplexed angular coverage of the MLA 220 lens element.
• the shape of the angular coverage cross section can be tailored in aspect ratio.
• the articulation rate around the x and y directions would be sufficient to ensure that the temporally generated light directions within the angular coverage have adequate duty cycle (modulation duration) within the modulation frame of the input image data.
• the modulation frame of the input image data is 60 image frames per second, which is typically referred to as 60 Hz image frame rate
• each of the light directions within each of the temporal angular coverage illustrated in Figure 14 will need to be modulated once per frame, thus making the articulation rate required to generate angular coverage illustrated in Figure 14 to be at least 180 Hz around either the x or the y axis.
• the articulation rate around either the x or the y directions for the illustration of Figure 14 would need to be at least three times the input image data frame rate.
• the angular coverage of the MLA lens element can be either overlapping or non-overlapping. In general the articulation rate of the
• QPI/MLA assembly 230 around either the x or y axis will have to be at least equal to the modulation frame rate of the input image data multiplied by a factor that equals to ratio of the size (in degrees) of the angular coverage long each axis to the size (in degrees) of the angular coverage along the same axis.
• the directions within the peripheral area of the expanded angular coverage could have less intensity than the interior region of the angular coverage.
• This intensity edge tapering effect would be somewhat similar to the Fresnel losses typically encountered at the edge of an optical system except in the case of the temporal spatio-optical light modulators, such an effect can be compensated by appropriate selection of the rate of the temporal articulation of the QPI/MLA assembly 230 of the temporal spatio-optical directional light modulator 200.
• each angular extent also being constituting an angular increment in articulation.
• the three contiguous individual angular extents in each direction can be considered as a two dimensional angular extent matrix as follows:
• This alternative is a discrete technique, namely to display angular extent 1 for an allotted time, then advance around a first axis by one angular increment and then display angular extent 2 for the same allotted time, then advance one more angular increment and display angular extent 3 for the allotted time, then advance one angular increment on the other axis to display extent 6 for the allotted time, then go back one angular increment on that axis and display angular extent 5 for the allotted time, etc.
• angular extent 9 is displayed for the allotted time, one could repeat 9 (continue displaying for twice the allotted time and then backtrack to avoid more than one angular increment in one axis at a time, though this would be expected to create a flicker unless a higher rate was used.
• a better approach would be to go from angular extent 9 to angular extent 1 , a jump of two angular increments on 2 axes at the same time.
• the temporal spatio-optical directional light modulators are realized by bonding the QPI/MLA assembly 230 (depicted in Figure 12) on the topside of the 2-axis gimbal assembly 1520 which is fabricated using multiple silicon substrate layers; namely, a hinge layer 1521 , a spacer layer 1528 and a base layer 1530 .
• the hinge layer 1521 of the 2- axis gimbal assembly 1520 is comprised of an outer frame 1522, an inner ring 1523 and the inner segment 1525 upon which QPI/MLA assembly 230 would be bonded (1525 is hereinafter also referred to synonymously as the device bonding pad 1525).
• the gaps between the outer frame 1522, the inner ring 1523 and the inner segment 1525 would be etched using standard semiconductor lithography techniques.
• the inner segment 1525 is physically connected along the x-axis to the inner ring 1523 by two silicon hinges 1524, each typically approximately in the range of 0.3-0.5 mm wide, which would act as the x-axis hinge and would also to define the neutral x-axis position of the gimbal and act as a mechanical resistance spring for the x-axis articulation.
• the inner ring 1523 is connected along the y-axis to the outer frame 1522 by two the silicon hinges 1526, each typically
• the two pairs of silicon hinges 1524 and 1526 constitute the pivot points of the 2-axis gimbal around which the x and y articulation would be performed.
• the inner segment 1525 of the hinge layer 1521 of the 2-axis gimbal assembly 1520 contains multiplicity of contact pads to which the QPI/MLA assembly 230 will be bonded using standard soldering techniques such as flip chip solder balls, thus making the inner segment 1525 become the bonding pad upon which QPI/MLA assembly 230 would be bonded.
• multiplicity of metal rails which connect a set of contact pads on the topside of the inner segment 1525 to a set of device contact pads 1527 placed along the periphery of the outer frame 1522 via the x-axis and y-axis silicon hinges 1524 and 1526.
• the set of contact pads on the topside of the inner segment 1525 are the contact pads that would provide electrical and physical contact to the backside of the QPI/MLA assembly 230.
• the height (or thickness) of the spacer layer 1528 would be selected to accommodate the vertical displacement of the corner of the inner segment 1525 together with the bonded QPI/MLA assembly 230 at the maximum actuation angle. For example, if the diagonal of the inner segment 1525 together measures 5 mm and the maximum articulation angle at the corner is 15°, then the thickness of the spacer layer 1528 should measure approximately 0.65 mm in order accommodate the vertical displacement of the corner of the inner segment 1525 at the maximum articulation.
• the articulation of the inner segment 1525 together with the bonded QPI/MLA assembly 230 would be accomplished using a set of electromagnets 1535 placed at the four corners of the backside of the inner segment 1525, and a set of permanent magnets 1536 placed on the topside of base layer 1530 in alignment with the four corners of the backside of the inner segment 1525.
• the electromagnets 1535 would be a coil having a metal core formed at wafer level using multilayer imprint lithography on the backside of the inner segment 1525.
• the permanent magnets 1536 would be a thin magnetic strip typically of neodymium magnet (Nd 2 Fei 4 B) or the like.
• Articulation of the inner segment 1525 together with the bonded QPI/MLA assembly 230 as described earlier would be accomplished by driving the set of electromagnets 1535 with an electrical signal having the appropriate temporal amplitude variation to affect the appropriate temporal variation in the magnetic attraction between the set of electromagnets 1535 and permanent magnets 1536 that would cause of the inner segment 1525 together with the bonded QPI/MLA assembly 230 to be temporally articulated as described earlier.
• the drive electrical signals to the set of electromagnets 1535 which are generated by the QPI device 210 and supplied to the set of electromagnets 1535 via the metal rails and contacts incorporated in the inner segment 1525 described earlier, would be made synchronous with the pixel modulation performed by the QPI device 210 to the extent that will enable the desired directional modulation of the intensity and color modulated light emitted from the pixel array of the QPI device 210.
• the temporal variation of the drive electrical signals to the set of electromagnets 1535 would be selected to enable the temporal angular articulation of the inner segment 1525 together with the bonded QPI/MLA assembly 230 around both of their x-axis and y-axis as illustrated in Figure 15.
• the maximum value ⁇ max of the temporal angular articulation a(t) illustrated in Figure 13B that can be achieved by embodiment 1500 of this invention would typically be in the range from ⁇ 15° to ⁇ 17°.
• the drive electrical signals to the set of electromagnets 1535 which are generated by the QPI device 210 and supplied to the set of electromagnets 1535 via the metal rails and contacts incorporated in the inner segment 1525 described earlier, would be comprised of a base component and a correction component.
• the base component of the drive electrical signals to the set of electromagnets 1535 would represent a nominal value and a correction component would be derived from an angular articulation error value generated by a set of four sensors positioned on the backside of the inner segment 1525 in alignment with the silicon hinges 1524 and 1526.
• sensors would be an array of infrared (IR) detectors placed on the backside of the inner segment 1525 in alignment with four IR emitters placed on the topside of the base layer 1530.
• the output values these four IR detector arrays will be routed to the QPI device, again via the metal rails and contacts incorporated in the inner segment 1525 described earlier, and used to compute an estimate of the error between the derived and the actual articulation angle which will be incorporated as a correction to the drive signals provided by the QPI to the set of electromagnets 1535.
• the sensors positioned on the backside of the inner segment 1525 could also be micro-scale gyros properly aligned to detect the actuation angle along each of the 2-axis of the gimbal.
• Figure 16 includes isometric views and side view illustrations of this embodiment.
• the embodiment 1600 of this invention is comprised of the 2-axis gimbal assembly 1620 with the QPI/MLA assembly 230 bonded on top of it.
• Figure 16 also shows an exploded isometric illustration of the embodiment 1600 that shows the constituent layers of the 2-axis gimbal assembly 1620 of this embodiment.
• the temporal spatio-optical directional light modulators are realized by bonding the QPI/MLA assembly 230 (depicted in Figure 12) on the topside of the 2-axis gimbal assembly 1620 which is fabricated using multiple silicon substrate layers; namely, a pad layer 1621 , a spring layer 1625 and a base layer 1630.
• the topside of the pad layer 1621 incorporates a multiplicity of contact pads to which the QPI/MLA assembly 230 is to be bonded using standard soldering techniques such as flip chip solder balls, thus making the topside of the pad layer 1621 being the bonding layer/contact pad 1623 upon which QPI/MLA assembly 230 would be bonded.
• the backside of the pad layer 1621 incorporates the spherical pivot 1635 which would be formed by embossing polycarbonate polymer on the backside of the pad layer 1621 at the wafer level using UV imprint lithography or the like.
• the pad layer 1621 together with the spherical pivot 1635 embossed on its backside will be referred to as hinged pad 1621 /1635.
• the elevation of the center of the spherical pivot 1635 determines the elevation of the x and y axes of the angular deflection.
• the topside of the base layer 1630 incorporates the spherical socket 1636 which would be formed by embossing of polycarbonate polymer on the topside of the base layer 1630 at the wafer.
• the base layer 1630 together with the spherical socket 1636 embossed on its topside will be referred to as the pedestal 1630/1636.
• the surface curvature the spherical pivot 1635 incorporated on the backside of the pad layer 1621 and the spherical socket 1636 incorporated on the topside of the base layer 1630 will be ⁇ matched in order to allow the hinged pad 1621 /1635 to make it a 2-axis articulated pad when placed on top of the pedestal 1630/1636.
• embossed surfaces of the spherical pivot 1635 and spherical socket 1636 will be of optical quality in terms of surface roughness in the order of a few nm RMS, possible friction between the two surfaces due to the articulation movement would be reduced by coating the surfaces of the spherical pivot 1635 and spherical socket 1636 with a thin layer (50-100 nm) of graphite.
• the hinged pad 1621 /1635 is retained in place within the surface curvature of the pedestal 1630/1636 by the spring layer 1625 which contains at each of its four corners a single spiral shaped spring 1626 that is etched into the spring layer 1625.
• the inner end of each of the four spiral shaped springs incorporates an inner bonding pad 1627 which corresponds to an identical contact pad 1622 located at the backside of the pad layer 1621 .
• Embedded within the spiral shaped springs 1626 are multiple metal rails that are used to route the electrical interface signals from its inner bonding pad 1627 to a set of edge contacts/pads 1628 located at the peripheral edge of the backside of the spring layer 1625.
• the edge contacts/pads 1628 on the backside of the outer end of the spring layer 1625 correspond to a matching set of bonding pads 1629 that are located at the peripheral edge of the base layer 1630.
• the edge contacts on the topside of the base layer 1630 are connected via metal rails embedded within the base layer to a set of device contact pads 1631 that are located on the backside of the base layer 1630.
• the four spiral shaped springs 1626 will be expanded when the backside of the edge contacts/pads 1628 of the spring layer 1625 is bonded to the topside bonding pad 1629 of the base layer 1630 and the inner bonding pad 1627 of the spiral shaped spring 1626 is bonded the corresponding contact pad 1622 on the backside of the pad layer 1621 .
• the four spiral springs 1626 become fully expanded and in that full expanded configuration they serve the multiple purposes of: (1 ) creating a spring load resistance needed to retain the spherical pivot 1635 within the spherical socket 1636; (2) creating the mechanical balance needed for sustaining the neutral position of the hinged pad 1621 /1635; and (3) routing the electrical interface signals from the device contact pads 1631 to the bonding layer/contact pad 1623 of the QPI/MLA assembly 230.
• the QPI/MLA assembly 230 is shown bonded to the topside bonding layer/contact pad 1623 of the pad layer 1621 .
• the full device assembly 1600 would be bonded using the contact pad 1631 located on the backside of the base layer to a substrate or printed circuit board using solder or eutectic ball grid array type bonding.
• the extended height of the spherical socket 1636 which would be selected to accommodate the vertical displacement of the corner of the hinged pad 1621 /1635 together with the bonded QPI/MLA assembly 230 at the maximum actuation angle.
• the thickness of the extended height of the spherical socket 1636 should measure approximately 1 .25 mm in order accommodate the vertical displacement of the corner of the of the hinged pad 1621 /1635 together with the bonded QPI/MLA assembly 230 at the maximum actuation angle.
• the actuation of the pad layer 1621 together with the bonded QPI/MLA assembly 230 would be accomplished using a set of electromagnets embedded within the spherical pivot 1635 and a set of permanent magnets embedded within the spherical socket 1636.
• the actuation electrical drive signal would be routed to electromagnets embedded within the spherical pivot 1635 in order to affect the actuation movement described in the earlier paragraphs.
• the base component of the actuation electrical drive signals to the electromagnets embedded within the spherical pivot 1635 would represent a nominal value and a correction component that would be derived from an angular articulation error value generated by a set of four sensors positioned on the backside of the pad layer 1621 .
• sensors are an array of infrared (IR) detectors placed on the backside of the pad layer 1621 in alignment with four IR emitters placed on the topside of the base layer 1630.
• the output values these four IR detector arrays will be routed to the QPI device, again via the metal rails and contacts incorporated in the pad layer 1621 described earlier, and used to compute an estimate of the error between the derived and the actual articulation angle which will be incorporated as a correction to the drive signals provided by the QPI device to the set of electromagnets embedded within the spherical pivot 1635.
• the sensors positioned on the backside of the pad layer 1621 could also be micro-scale gyros properly aligned to detect the actuation angle along each of the 2-axis of the gimbal.
• the permanent magnets embedded within the spherical socket 1636 would be a thin magnetic rods or wires, typically of neodymium magnet (Nd 2 Fei 4 B) or the like, and would be shaped to provide a uniform magnetic field across the curved cavity of the spherical socket 1636.
• Actuation of the pad layer 1621 together with the bonded QPI/MLA assembly 230 as described earlier would be accomplished by driving the set of electromagnets embedded within the spherical pivot 1635 with an electrical signal having the appropriate temporal amplitude variation to affect the appropriate temporal variation in the magnetic attraction between the set of electromagnets embedded within the spherical pivot 1635 and permanent magnets embedded within the spherical socket 1636 that would cause of the pad layer 1621 together with the bonded QPI/MLA assembly 230 to be temporally articulated as described earlier.
• the drive electrical signals to the set of the set of electromagnets embedded within the spherical pivot 1635 which are generated by the QPI device and routed via the metal rails and contacts incorporated on the pad layer 1621 described earlier, would be made synchronous with the pixel modulation performed by the QPI device to an extent that will enable the desired directional modulation of the intensity and color modulated light emitted from the pixel array of the QPI device.
• electromagnets embedded within the spherical pivot 1635 would be selected to enable the temporal angular articulation of the pad layer 1621 together with the bonded QPI/MLA assembly 230 along both of their x-axis and y-axis as illustrated in Figure 15.
• the maximum value ⁇ a max of the temporal angular articulation a(t) illustrated in Figure 15 that can be achieved by the embodiment 1600 of this invention would typically be in the range from ⁇ 30 ° to ⁇ 35°.
• the two exemplary embodiments 1500 and 1600 of this invention differ mainly in the maximum value max oi the temporal angular articulation a(t) each can achieve and in the outer area each embodiment needs beyond the boundary of the QPI/MLA assembly 230.
• the 2-axis gimbal is fully accommodated within the footprint area of the QPI/MLA assembly 230 (hereinafter refer to a zero-edge feature) while as illustrated in Figure 15 in the embodiment 1500 of this invention the 2-axis gimbal is accommodated at the outer periphery of the QPI/MLA assembly 230 outer boundary.
• the maximum value a max of the temporal angular articulation a(t) embodiment 1600 can achieve could possibly be twice as large as what could be provided embodiment 1500.
• the larger maximum value a max of the temporal angular articulation a(t) that can be accomplished by the embodiment 1600 comes at the expense of requiring larger vertical height than the embodiment 1500.
• the zero-edge feature of the embodiment 1600 makes it more suitable for being tiled to create a large area display while the low profile (low height) feature of the embodiment 1500 makes it more suitable for creating compact displays for mobile applications.
• the angular extent ⁇ of the MLA 220 micro lens system 610, 620 and 630 can be made either larger or smaller than the ⁇ 15° of the exemplary embodiment of Figure 6 through appropriate design selection of the refracting surfaces of the micro lens system 610, 620 and 630 or by increasing or decreasing the number of its optical elements. It should be noted, however, that for a given resolution in terms of number of pixels within the pixel modulation group G i ; changing the angular extent ⁇ of the MLA 220 micro lens system would result in a change in the angular resolution (separation) between the directionally modulated light beams emitted by the QPI/MLA assembly 230 of the temporal spatio-optical directional light modulators of this invention.
• the maximum value of the articulation angle a max comes into the tradeoff as a parameter that can be used either to increase the angular extent of the directional modulation or the spatial resolution that can be achieved by the temporal spatio-optical directional modulators.
• the temporal spatio-optical light modulators of this invention differ in one very important aspect in that it generates, at any given instance of time, a multiplicity of light beams that are directionally modulated simultaneously.
• the multiplicity of directionally modulated light beams would be temporally multiplexed by the articulation of the gimbaled QPI/MLA assembly 230 to expand the directional modulation resolution and angular extent.
• the gimbaled QPI/MLA assembly 230 As explained earlier (see Figure 14), as the gimbaled QPI/MLA assembly 230 is articulated a new set of directionally modulated light beams are added as some drop off temporally in a pipeline fashion until the expanded angular extent provided by the temporal spatio- optical light modulators of this invention is fully covered. Accordingly, at any given instant the full emissive aperture of the gimbaled QPI/MLA assembly 230 is utilized to accumulate the desired intensity at any given direction as that direction remains temporally within the coverage of the articulated aperture of QPI/MLA assembly 230.
• the response time the temporal spatio-optical light modulators of this invention can be made to be commensurate with the image data input rate with minimal latency.
• QPI/MLA assembly 230 of the temporal spatio-optical directional light modulators of this invention can be made in a non-stop pattern that would result in minimal or no blanking of the emissive aperture of the gimbaled QPI/MLA assembly 230 as it is articulated across the expanded angular extent of the temporal spatio-optical light modulators of this invention.
• the slow response time, poor efficiency and large volume drawbacks of prior art directional light modulators are all substantially overcome by the temporal spatio-optical light modulators of this invention.
• Figure 8 and Figure 9 illustrate the operational principles of the temporal spatio-optical directional light modulators.
• Figure 8 the directional modulation addressability that can be achieved by the pixel group G t would be accomplished through the addressability of the (nxn) pixels comprising the modulation group G t along each of its two axes x and y using m-bit words.
• Figure 9 illustrates the mapping of the light emitted from (nxn) pixels comprising the QPI pixel modulation group G t into individual directions within the three dimensional volume defined by angular extent 0 of the associated MLA 220 micro lens element such as that of the exemplary embodiment illustrated in Figure 6.
• the directional modulation angular extent provided by the lens elements of the QPI/MLA assembly 230 will be temporally extended by the maximum articulation angle ⁇ max provided by the gimbal.
• the directional modulation angular extent provided by the temporal spatio-optical directional light modulators of this invention would be temporally extend over an angular coverage totaling ⁇ (0 + a max ).
• the number of light modulation directions that can be generated by the temporal spatio-optical directional light modulators of this invention would be (3nx3n), where (nxn) is the size, in terms of number of QPI pixels, of the pixel groups G t associated with one of the MLA 220 lens elements.
• the temporal spatio-optical directional light modulator would offer an expanded directional modulation resolution to 9x the directional modulation resolution provided by QPI/MLA assembly 230.
• the directional modulation resolution provided by the temporal spatio-optical directional light modulators would [n(0 + max )/0] 2 within an angular extent that extends over an angle of ⁇ (0 + a max ).
• spatial modulation would also be possible using an array of (NxM) of the QPI pixel modulation groups G t such as that described in the previous design example.
• the temporal spatio-optical directional light modulators of this invention would comprise an array of (16x16) directional modulation groups G t and when a QPI with (5x5) micron pixel size is used, the total size of the temporal spatio-optical directional light modulator would be approximately 10.24x10.24 mm.
• the light emitted from such a spatio-optical directional light modulators of this invention can be spatially modulated at a resolution of (16x16) and directionally modulated at a resolution of 147,456 within the angular extent ⁇ 45°, and can also be modulated in color and intensity in each direction.
• the spatial and directional modulation resolutions of the temporal spatio-optical light modulator in terms of the number of individually addressable directions within a given the angular extent would be determined by selecting the resolution and pixel pitch of the emissive micro emitter array QPI device 210, the pitch of the MLA 220 lens elements, the angular extent of the MLA 220 lens elements and the maximum articulation angle of the modulator gimbal.
• the MLA lens system can be designed to allow either wider or narrower angular extent
• the gimbal design can be selected to allow either wider or narrower articulation angle
• the number of pixels within each modulation group can be selected either smaller or larger in order to create a temporal spatio-optical directional light modulator that can achieve any desired spatial and directional modulation capabilities following the teachings provided in the preceding discussion.
• any desired spatial and directional modulation capabilities can be realized using the spatio-optical directional light modulators of this invention.
• the previous example illustrated how spatio-optical directional light modulators of this invention with (16) 2 spatial resolution and (3x128) 2 directional resolution can be implemented using a single 10.24x10.24 mm QPI device 210.
• the temporal spatio-optical directional light modulators of this invention can be implemented using a tiled array comprising multiplicity of smaller spatial resolution temporal spatio-optical directional light modulators of this invention.
• the temporal spatio-optical directional light modulator of the previous example that uses a single QPI device 210 which by itself would have an exemplary width, height and thickness of 10.24x10.24x5 mm; respectively, can be used to create the larger resolution version illustrated in Figure 1 1 which would have the dimension of 3.07x3.07x0.5 cm in width, height and thickness;
• the resultant temporal spatio-optical directional light modulator would have a (30x16) 2 spatial resolution and (3x128) 2 directional resolution and would measure
• Figure 1 1 by bonding multiplicity of the temporal spatio-optical directional light modulators of the previous example to a backplane using electrical contacts of the micro ball grid array (MBGA) located on its backside, which given the zero-edge feature of embodiment 1600, would make it possible to realize seamless tiling of a multiplicity of such directional light modulator devices to implement any desired size of the temporal spatio-optical directional light modulators.
• MBGA micro ball grid array
• the size of the array of temporal spatio-optical directional light modulators illustrated in Figure 1 1 can be increased to the extent needed to realize any desired spatial resolution. It is also possible to tradeoff the directional resolution of the temporal spatio-optical directional light modulators for an increased spatial resolution. For example, if the pixel modulation group size is reduced to (64x64), the (3x3) array illustrated in Figure 1 1 would provide (3x32) 2 spatial resolution and (3x64) 2 directional resolution. It is worth noting that the array of temporal spatio-optical directional light modulators which offers the expanded spatial aperture illustrated in Figure 1 1 is made possible by the zero-edge feature described earlier of the temporal spatio- optical directional light modulator embodiment 1600 of this invention.
• Figure 8 illustrates the two dimensional addressability of each of the modulation group Gi using m-bit resolution for the directional modulation.
• light emitted from (2 m x2 m ) individual pixels of the modulation group G t is mapped by its associated MLA 220 elements into 2 2m light directions within the angular extent ⁇ 0 of the associated MLA micro lens element.
• the angular coordinates ⁇ , ⁇ ) of the emitted light beam is given by:
• the spatial resolution of the temporal spatio-optical directional light modulators of is defined the coordinates ⁇ X, Y) of each of the individual modulation group G t within the two dimensional array of modulation groups comprising the overall temporal spatio-optical directional light modulator.
• the temporal spatio-optical light modulators would be capable of temporally generating (modulating) a light field described by the spatial coordinates ⁇ X, Y) defined by its modulation group array and the directional coordinates ⁇ , ⁇ ) with the latter being defined by the values of the coordinates
• Figure 1 which illustrates an exemplary embodiment of the data processing block diagram of the spatio-optical directional light modulator, is also applicable to the temporal spatio-optical embodiments of the invention.
• the prior description of using 1 6-bit for representing the directional modulation and the typical 24-bit for representing the modulated light intensity and color in each direction is also applicable to the temporal spatio-optical embodiments of this invention.
• the temporal spatio-optical directional light modulators of this invention can be used to implement a 3D display with an arbitrary size that is realized, for example, as a tiled array of multiplicity of temporal spatio-optical directional light modulator devices such as that illustrated in Figure 1 1 .
• the expanded angular extent that can be realize by the temporal spatio-optical directional light modulators would enable the realization of 3D displays that are volumetrically compact and provide a large viewing angle, yet without the use of bulky and costly optical assemblies.
• the level of volumetric compactness that can be achieved by the temporal spatio-optical directional light modulators will enable the realization of both desk top as well as possibly mobile 3D displays.
• the angular resolution capabilities of the temporal spatio-optical directional light modulators of this invention make them capable of generating a VAC-free 3D images that will not cause viewers' visual fatigue.
• the light field modulation capabilities of the temporal spatio-optical directional light modulators also make it the underlying bases of 3D light field displays that can be used to implement a synthetic holography 3D displays.
• the temporal spatio-optical directional light modulator When the temporal spatio-optical directional light modulator is used as a 2D display its light angular extent will be that of associate with its MLA 220 micro lens element plus the articulation angle of its gimbal ⁇ (0 + a max ) with the pixel resolution of the individual modulation group G t leveraged to achieve higher spatial resolution.

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