Structures for modifying leaky mode light

A method and system for using laser-induced structures to direct light to exit the bottom of a leaky mode device, and further to divide leaky mode light into multiple orders, and to implement one or more pulsing/strobing patterns such that a field of view is increased for a viewer, or the view zone is increased for a viewer. A leaky mode device may comprise a substrate, a surface acoustic wave (“SAW”) transducer, a waveguide having a higher refractive index than the substrate, an input region for input light, and laser induced structures such as grating. The SAW transducer may be positioned on a top surface of the substrate, and may be configured to emit a SAW wave to propagate across the substrate. The waveguide may be positioned below the SAW. The input wave region may be configured to couple light onto the waveguide. When light is coupled onto the waveguide, the refractive index may change such that the light in the waveguide exits the waveguide as leaky mode light and interacts with the laser-induced grating, which is below the waveguide. The laser-induced grating is configured to divide the leaky mode light into multiple orders, each bent at a different angle.

BACKGROUND OF THE INVENTION

Leaky mode systems may be used for holographic video, e.g., flat-screen, scanned aperture, and near-eye holographic video systems. In a leaky mode system, which generally comprises multiple leaky mode devices, surface acoustic waves (“SAW”) for a leaky mode device are generated by a transducer that encodes electrical information as a pattern of surface acoustic waves. This surface acoustic wave pattern acts both to mode couple light so that it is no longer guided and also to encode the light with holographic information. The leaky mode light propagates to form part or all of a holographic image.

One of the shortcomings in leaky mode light systems is that light exits the edge, rather than the bottom, of the device. This means that the device output aperture depends on the device thickness. Larger apertures mean thicker, more expensive, harder-to-process devices. Because in existing leaky light mode devices light exits the edge, but not the bottom, such devices can be combined only in one-dimensional arrays (which might themselves be one dimensional arrays). Otherwise, the light exit would be blocked.FIG. 6shows an example of a one-dimensional array600of leaky mode devices605, with respective transducers610, respective SAWs620, and respective light630exiting from side of leaky mode device605n.

Additionally, fabricating gratings in leaky mode devices can be difficult and expensive when gratings have high spatial frequency. A grating in a leaky mode device is a periodic structure, usually etched into the bottom surface of the leaky mode substrate. The period of these gratings is typically around 300 nm. This grating structure takes leaky mode light traveling at approximately 10 degrees internally and bends it to 90 degrees as it exits the bottom surface of the device substrate. Standard photolithographic processes can be used to create patterns down to 1 μm features size. However, output gratings in lithium niobate meant to outcouple leaky mode light typically have grating periods around 300 nm. At this feature size, interference lithography, contact lithography, or more commonly, ebeam lithography must be used. But these fabrication techniques are difficult, expensive, and suffer from other shortcomings. Interference lithography has limited control of the grating pattern (only uniform gratings). Contact lithography requires special, thin, fragile flex masks that degrade with use. Ebeam lithography writes the pattern serially and is considered a low-throughput, high cost technique.

Another problem is that a bottom exit grating will reduce the field of view of a leaky mode near-eye display as compared with an edge-exit leaky mode display. Leaky mode modulators change the angle of light during mode conversion by adding or subtracting the spatial frequency of a surface acoustic wave to the spatial frequency of the light in the guide input mode. A grating output coupler adds or subtracts spatial frequencies in opposition to the grating formed by surface acoustic waves, essentially undoing some of the angular deflection.

Additionally, even when bottom exit gratings are used to direct and guide light to exit out the bottom of a leaky mode device, when a user moves it ay appear that that a virtual point is shifting with the user, rather than appearing to the user that the virtual point remains at the same point in space regardless of how a user has shifted,

What is needed is improvements to leaky mode devices to facilitate non-grating light exit from the bottom of a leaky mode device and/or to mitigate and/or overcome edge exit for leaky mode light devices, and further to mitigate obstacles and other issues associated with bottom exit in leaky mode devices.

BRIEF SUMMARY OF THE INVENTION

A system and apparatus for improvements to leaky mode devices are disclosed.

In one embodiment, a structure-modified leaky mode device (“SMLMD”) may comprise a leaky mode device that includes light deflection structures in the interior of the leaky mode device to deflect, i.e., redirect, leaky mode light, i.e., light from an illuminated SAW, toward the bottom of the leaky mode device before the light translates laterally from the side edges of the leaky mode device. The structures may also divide the light from an illuminated SAW into different orders. In general, each order is light bent at a different angle. Such structures may be gratings, mirrors, prisms, or similar structures. These structures may be laser-induced, which allows for structures internal to the leaky mode device. The structures may also be fabricated on the surface of a leaky mode device.

In one embodiment, an SMLMD may comprise a substrate, a SAW (surface acoustic wave) transducer, input region light, a waveguide, guided light, and structures160. The Guided light may guided in the waveguide under the SAW.

When the transducer generates a SAW, the SAW propagates across the surface of the leaky mode device. If the SAW is illuminated by strobed light from the input region light, leaky mode light leaks into the substrate and interacts with the structures. In one embodiment, the structures divide the light into multiple orders, each bent at a different angle.

If strobing is timed properly, the orders into which leaky mode light are divided may be used to generate an increased field of view and/or an increased view zone.

DETAILED DESCRIPTION OF THE INVENTION

This Application claims priority as a continuation-in-part to U.S. Non-provisional application Ser. No. 15/955,670, titled “Structures for Modifying Leaky Mode Light,” the first inventor of which is Daniel Smalley, which was filed on Apr. 17, 2018, and which in turn claims priority to U.S. Provisional Application No. 62/486,326, titled “Structures for Modifying Leaky Light Mode,” the first inventor of which is Daniel Smalley, which was filed on Apr. 17, 2017, and which is incorporated herein by reference in its entirety.

A system and method are disclosed for using structures to redirect leaky mode light to bottom exit instead of side exit, and further to split light from illuminated SAWs into different orders, and further to overcome and/or mitigate drawbacks associated with bottom exit leaky mode light for flat-screen and near-eye architectures.

Table of Reference Numbers from Drawings:

The following table is for convenience only, and should not be construed to supersede any potentially inconsistent disclosure herein.

ReferenceNumberDescription100leaky mode device (SMLMD)101bottom of leaky mode device102side of leaky mode device105substrate110SAW transducer120SAW moving from left to right121SAW moving from left to right125direction of propagation of SAW127redirected leaky mode light130input light140waveguide150guided light160structures170a-blight exiting side edge of substrate180aorder = −3 light after light from illuminated SAW isdivided by structures into multiple orders180border = −2 light after light from illuminated SAW isdivided by structures into multiple orders180corder = −1 light after light from illuminated SAW isdivided by structures into multiple orders180dorder = 0 light after light from illuminated SAW isdivided by structures into multiple orders180eorder = 1 light after light from illuminated SAW isdivided by structures into multiple orders202structures (medium periodicity)204structures (high periodicity)206structures (low periodicity)208structures (chirp pattern)212channel-specific structures including pulsing214channel-specific structures including pulsing216channel-specific structures including pulsing218channel-specific structures including pulsing305direction of propagation of SAW waves through substrate310first launched SAW311leaky mode light resulting from interaction between SAW310 and input light320second launched SAW321leaky mode light resulting from interaction between SAW320 and input light330high angle340small diffraction angle350uniform laser-induced grating360a-dhigher orders of diffracted light405leaky mode channel410diffuser420a-blenslets425a-bleaky mode light600one-dimensional array of leaky mode devices605nleaky mode device610ntransducer620nSAW630nlight exiting from side of leaky mode device 605n710virtual image point720structure(s)721pulsed SAW at time t1722pulsed SAW at time t2723pulsed SAW at time t3731-34redirected light737leaky mode light resulting from interaction of SAW 721with input light 130740viewer740aviewing position 1740bviewing position 2740cviewing position 3750direction of SAW propagation across leaky mode device805a-nvirtual image points806a-nleft ray for user perception of virtual point 805a-n807a-nright ray for user perception of virtual point 805a-n808a-nleft ray of light associated with SAWs 821a-n809a-nright ray of light associated with SAWs 821a-n810viewer820structure(s)821a-nSAWs associated with virtual points 805a-n822SAW at time t2823SAW at time t3860redirected light

A system and method arc: disclosed for using structures to redirect leaky mode light to facilitate bottom exit for light in leaky mode light devices used for flat-screen and near-eye architectures, holographic video architectures, as well as other applications of leaky mode light devices. The system and method disclosed herein are further useful for splitting light from illuminated SAWs into different modes to facilitate, e.g., increased view angle and increased field of view in a bottom exit leaky mode apparatus. As used herein, “leaky mode device” and “leaky mode light device” are equivalent. Bottom exit in leaky mode devices enables tiling, i.e., two-dimensional arrays, because light may exit the bottom of a leaky mode device even if the sides of the leaky mode device are blocked by other leaky mode devices in a two-dimensional array or tiling arrangement of leaky mode devices.

The system disclosed herein shall be referred to below as a “Structure-Modified Leaky Mode Device: (SMLMD). In general, bottom exit is facilitated using grating or mirror structures on the surface of or internal to a leaky mode device.

In one embodiment, a SMLMD may comprise a leaky mode device that includes light deflection structures in the interior of the leaky mode device to deflect, i.e., redirect, leaky mode light, i.e., light from an illuminated SAW, toward the bottom of the leaky mode device before the light translates laterally from the side edges of the leaky mode device. The structures may also divide the light from an illuminated SAW into different orders. In general, each order is light bent at a different angle. Such structures may be gratings, mirrors, prisms, or similar structures. These structures may be laser-induced, which allows for structures internal to the leaky mode device. The structures may also be fabricated on the surface of a leaky mode device.

Deflecting or redirecting leaky mode light through the bottom of a leaky mode device allows a viewer to see the output directly below the interaction region. Dividing light from an illuminated SAW into different modes allows for creating an increased view zone and and/or an increased field of view.

In one embodiment, as shown inFIG. 2b, SMLMD100(which may also be referred to as a “leaky mode modulator” or a “leaky mode channel”) may comprise substrate105, SAW (surface acoustic wave) transducer110, input region light130, waveguide140, guided light150, and structure160. Guided light150is guided in waveguide140under SAW120.

In one embodiment, waveguide140is a part of the substrate that has been modified to have a higher refractive index. For example, in one embodiment, waveguide140may be the same material as substrate105, but waveguide140may have been modified by proton exchange to create a waveguide region to increase its refractive index. The increased refractive index may apply for only one polarization, so that when mode-coupling occurs, resulting in a polarization change, waveguide140effectively no longer exists, and light150leaks into substrate105.

In one embodiment, a laser-induced structured may be created by a femtosecond laser beam pulse.

SAW120and light in waveguide140may move collinearly or contra-linearly. The system works similarly if the light and the acoustic waves are moving together, i.e., collinearly, or in opposite directions, i.e., contra-linearly. As shown inFIG. 2b, SAW120and light150from input light130are moving collinearly. Both are moving left-to-right.

As shown inFIG. 2b, and described herein, SAW transducer110generates surface acoustic wave (SAW)120, which may propagate across the surface of substrate105.

As shown inFIG. 2b, waveguide140is configured to guide light150. Light150may be coupled onto waveguide140from air or from substrate105by grating, prism, or by edge coupling, or some other method in light input region130. As described herein above, because waveguide140has a higher refractive index than the refractive index of substrate105, light150tends to remain in and be guided by waveguide140. However, when light150in waveguide140interacts with SAW120, and mode coupling occurs, along with a polarization change and associated loss of the increased refractive index, waveguide140effectively no longer exits and/or acts as a waveguide140, and light150leaks into substrate105.

FIG. 2bshows an example of light150interacting with SAW120. When light150interacts with SAW120, i.e., by “colliding” when SAW120above light150, the leaked light from the interaction interacts with grating160, thereby redirecting light150and dividing light150into multiple orders.

FIG. 2ashows an example of a leaky mode device without structures as disclosed herein. As shown inFIG. 2b, without structures as described herein, light paths170aand170bexit from side102of substrate105and are not divided into multiple orders.

As shown inFIG. 2b, the leaked light from the interaction between SAW120and light150is directed in a downward direction. In one embodiment, if SAW120is moving left-to-right and light150is moving left-to-right, then the interaction between SAW120and light150may result in leaked light moving downward and to the left, as shown by leaky mode light127inFIG. 2b.

As shown inFIG. 2b, structures160may interact with leaky mode light170to divide leaky mode light into multiple orders180a-e. An order is a redirection of divided leaky mode light127. Each order represents a redirection of leaky mode light127at a different angle. For example, as shown inFIG. 2b, structures160may divide leaky mode light127into order180a(the minus 3 order), order180b(the minus 2 order), order180c(the minus 1 order), order180d(the 0 order), and180e(the plus 1 order). The 0 order represents the order that travels in the same direction as leaky mode light127. The negative orders represent orders that are offset from the 0 order in the direction opposite the direction in which SAW120is traveling. The positive orders represent orders that are offset from the 0 order in the same direction in which SAW120is traveling.

Normally, the viewer would also see scatter from waveguide140. This scatter can be reduced, however, by using a polarizer to eliminate noise or by using a low-loss waveguide such as a reverse proton exchange waveguide or a soft proton exchange waveguide.

In one alternate embodiment, the redirection structures160in a leaky mode device may comprise two (or more) gratings instead of one grating. By using multiple gratings, e.g., two gratings, the gratings can be of lower spatial frequency and may therefore be easier and less expensive to manufacture because the features of such gratings will be larger. Such gratings may be laser-induced.

If the gratings are Bragg gratings, then only one order results. Light passing through a thin grating will create several outputs, each at a different angle. Beams at angles higher than the illumination beam are called positive orders and those below the illumination beam are called lower orders. The spacing of the grating determines the angular separation of the modes. If the gratings are not Bragg gratings but are instead Raman Nath gratings or thin gratings, then many orders result from the use of such gratings. Although having multiple orders results in loss of power for all of the multiple order, and also results in the complication of having many simultaneous light beams instead of one, an embodiment with multiple orders results in beneficial increased filed-of-view in near-eye displays.

One embodiment may employ two gratings for bottom exit. In such an embodiment, the first grating may be used to create multiple orders and to select the angular separation of the multiple orders. The second grating may be used to rotate the orders toward the viewer. By carefully adjusting (1) the separation between the surface acoustic wave train that creates the leaky modes, (2) the distance to the first grating, and the distance to the second grating, the field of view for a viewer may be increased. Using this approach results in creation of a new version of a holographic image that has been rotated to a different angle and is visible to a viewer different time. The aggregate result of these orders is a wide field of view.

Using more than two gratings may modify the angle and potentially increase the number of orders.

In one embodiment, instead of including a grating for bottom exit, a leaky mode device may include a laser-induced mirror array. This approach avoids reduction of angular scan because the momentum of the light is not changed. Such an approach is viable for near eye applications, holographic video, as well as other leaky mode applications.

In one alternate embodiment, as shown inFIGS. 3aand 3b, SMLMD100may be a multichannel leaky mode device. For example,FIG. 3ashows a bottom perspective cross section view SMLMD100that has four leaky mode channels respective structures202,204,206, and208beneath each of the four leaky mode channels. Structures202,204206, and208may be located beneath a first leaky mode channel, a second leaky mode channel, a third leaky mode channel, and a fourth leaky mode channel, respectively.

As shown inFIG. 3a, structures202,204,206, and208may have differing periodicities or spatial frequencies, or may differ from each other in other patterns, or may arbitrarily differ from each other. As shown inFIG. 3a, structure202may have a medium periodicity, structure204may have a high periodicity, structure206may have a low periodicity, and structure208may have a chirped periodicity pattern.

FIG. 3bshows a bottom-perspective cross section view of multichannel SMLMD100in an alternate embodiment in which structures212,214,216, and218vary along individual channels, and in which pulsing may be used to get the leaky mode output to address particular structure regions. For example, structures212, which may correspond to and be below a first leaky mode channel in SMLMD100, may begin (from left to right) with a low periodicity pulse and alternate between a low periodicity pulse and a high periodicity pulse. Structures214, which may correspond to and be below a second leaky mode channel in SMLMD100, may, begin (from left to right) with a high periodicity pulse and alternate between a high periodicity pulse and a low periodicity pulse. Structures216, which may correspond to and be below a third leaky mode channel in SMLMD100, may begin (from left to right) with two low periodicity pulses and alternate between two low periodicity pulses and two high periodicity pulses. And structures216, which may correspond to and be below a third leaky mode channel in SMLMD100, may begin (from left to right) with two high periodicity pulses and alternate between two high periodicity pulses and two low periodicity pulses.

FIGS. 4a, 4b, 4cshow side-perspective cross section views of multichannel SMLMD100corresponding to structures214at t2, and t3respectively.FIGS. 4a, 4b, and 4cshow how pulsing SAW120at times t1, t2, and t3, as SAW120propagates from left to right across surface of leaky mode device100, may result in the leaky mode light from SAW120interacting with different portions for structures214.

In another alternate embodiment, as shown inFIG. 5, structures350in SMLMD100may split a single input beam into multiple beams, e.g., a grating may give rise to multiple orders. These orders may be combined, e.g., using light pulsing with SAWs310and320, to create high-angle information not contained in light from the original leaky mode.

FIG. 5shows how a near-eye display using different diffracted modes may create a wide view zone. For example, a SAW may be pulsed at a first time such that leaky light from the SAW is divided into multiple orders and one of the orders is directed toward a first view position. The same SAW may subsequently be pulsed at a second time such that leaky light from the SAW is divided into multiple orders and one of the orders is directed toward a second view position. Using the appropriate pulsing pattern (for applying input light), a user may move from the first view position to the second view position, and a virtual point may appear to the user to have remained at the same point in space, and the user may further perceive that he/she is seeing a different angle of the virtual point—as if virtual point were an actual point and the user had actually moved.FIGS. 8a-8cillustrate and explain this embodiment and phenomenon in greater detail.

FIG. 5further shows how a near-eye display using different diffracted modes may create a wide field of view. For example, a first SAW310encoding a first virtual point may be pulsed at a first time such that leaky light from SAW310is divided into multiple orders and one of the orders is directed toward a view position. A second saw320may be pulsed such that leaky light from SAW320is divided into multiple orders and one of the orders is directed toward the same view position. This approach may be scaled to a large number of virtual points (e.g., thousands, ten thousands, hundred thousands, or more. Using the appropriate pulsing pattern (for applying input light), a user may see a wide field of view as if the virtual points were really there.FIGS. 9a-9eillustrate and explain this phenomenon in greater detail.

It should be noted that, because the pulsing/illumination speed may be much faster than a human eye is able to perceive, many pulsing events may occur but be perceived by a user as having occurred simultaneously, e.g., SAWs representing numerous virtual points may be illuminated at a very high speed, thus resulting in presentation of many orders from many SAWS to a user, the user will perceive that the orders are being presented simultaneously even though the input light is pulsing/illuminating SAWs in a serial manner.

FIGS. 6a-dshow alternate embodiments in which structures are placed by photolithography on the bottom surface of SMLMD100to further redirect light, e.g., to create a vertical focus. For example,FIG. 6ashows a bottom-angle-perspective view of SMLMD100with a diffuser410on bottom surface101.FIG. 6bshows a side cross-section view of SMLMD100as shown inFIG. 6a.FIG. 6cshows a side cross-section view of SMLMD100wherein lenslets420aand420b, comprising a lenslet array, have been added to bottom101of SMLMD100, and wherein each lenslet420aand420bmay be responsible for the output of one channel, e.g., lenslet420amay be responsible for the output of leaky mode channel425aand lenslet420bmay be responsible for the output of leaky mode channel425b.FIG. 6dshows a side cross-section view of SMLMD100, wherein volume hologram430has been added to create focus for the overlapping output of many leaky mode channels.

Various beneficial effects can be generated by the pattern used to illuminate a SAW, i.e., the illumination pattern or pulsing pattern. A pulsing pattern generally comprises a pattern for turning input light130on and off. This may be referred to as e.g., chirping, pulsing, strobing, or a chirp pattern, a pulse pattern, or a strobe pattern.

In one embodiment, a pulse may be approximately 110 nanoseconds.

FIGS. 8a-cand 9a-dprovide a detailed illustration of exemplary embodiments for providing a wide view zone and wide view field, respectively.FIGS. 7a-eillustrate how the structures, as disclosed herein, divide leaky mode light into different orders that are bent at different angles. For the sake of explanation,FIGS. 7a-eseparately show multiple orders from the same pulse to the same SAW, even though in practice the orders are generated simultaneously when a SAW is pulsed.FIG. 7dshows the 0 order, i.e., the order that does not bend the leaky mode light at all.FIG. 7cshows the minus 1 order.FIG. 7bshows the minus 2 order.FIG. 7ashows the minus 3 order.FIG. 7eshows the plus 1 order. The angles at which various orders are bent may be adjusted or changed based on the pattern of structures other characteristics of a leaky mode light device system, e.g., size of the leaky mode device, distance from surface to structures, etc.)

FIGS. 8a-cshow one exemplary effect that may be generated based on an arrangement of a set of structures and a chirping pattern. As shown inFIGS. 8a-c, it may be desirable to display a virtual point710so that it is visible at a wide view angle, e.g., at view positions740a,740b, and740c, and so that it is also appears at the proper virtual location and perspective from each view position. As shown inFIG. 8a, a SAW721, traveling from left to right, at time t1may be illuminated, pulsed, or strobed with light130such that the resulting leaky mode light737interacts with structures720, thereby generating the minus 3 order, which is directed toward view position740a. If, as shown inFIG. 8b, the same SAW721is strobed at a time t2, the resulting leaky mode light737interacts with structures720, thereby generating the minus 2 order, which is directed toward view position740b. Similarly, as shown inFIG. 8c, the same SAW721may be strobed at a time t3, and the resulting leaky mode light737interacts with structures720, thereby generating the minus 1 order, which is directed toward view position740c. In addition to making virtual point710visible from view positions740a,740b, and740c, i.e., increasing or widening the view zone, virtual point710appears to the viewer to be at the same actual location, and also appears from the expected perspective or angle.

In this manner, by timing the strobing by input light130, a wider view angle may be created, i.e., a user may be able to see virtual point710from position740a,740b, and740c, and at the proper perspective.

In one embodiment, the strobing pattern may have awareness (e.g., through one of many sensors or other approaches known in the art) of a viewer's view position, and may determine strobing timing and frequency based on the viewer's view position. This approach may alleviate some interference that may result from orders that are directed toward more than one view position. As already described herein, because strobing can occur at a much faster rate than the perception ability of the human eye, this approach may generate an image that appears to a viewer as a stable image, even though thousands, or hundreds of thousands, or millions of virtual points may be generated serially by pulsing SAWs.

As illustrated inFIGS. 9a-e, the system described herein may be applied to increase the view zone (e.g., the size of the viewable virtual area) available at one location. For example,FIGS. 9a-eshow virtual points805a-n. This is a simplified example for explanatory purposes. An actual implementation would likely have thousands, tens of thousands, hundreds of thousands, or millions of virtual view points,

As shown inFIG. 9a, it may be desirable to display virtual points805a-nat view position810. View lines806a-nand807a-nrepresent perceived light, at view position810, from virtual points805a-n.

FIG. 9bshows that by pulsing SAW821a, virtual point805amay be displayed to a viewer at view position810. Virtual point image bounds806aand807arepresent the bounds of the image of virtual point805aas perceived by a viewer at view position810. Bounds808aand809arepresent the bounds of the light as it actually travels from SAW821aafter SAW821ais illuminated or strobed by input light130.FIGS. 9c.9d, and9eare analogous to points805b,805c, and805n, respectively. As shown inFIGS. 9b-e, by pulsing SAWs821a-n, which are associated with virtual points805a-n, at the appropriate times, a viewer at view position810will perceive virtual points805a-nas if they were located at the actual locations shown inFIGS. 805a-n, even though the light for virtual points805a-nis actually originating from SAWs821a-n. Because light may be pulsed much more quickly that a human eye can perceive, and SAWs can traverse leaky mode devices much more quickly than a human eye can perceive, a user may see a wide field of view, which may appear to be stable and persistent, even though individual virtual points in the field of view are being generated serially.

As shown inFIG. 10, one exemplary method may comprise using a SMLMD to increase a view zone of a virtual image.

At step1010, a computing device may generate or receive data comprising a representation of a virtual point.

At step1020, the computing device may transmit the data representation of the virtual point to a transducer, which may encode the virtual point as a SAW that propagates across the surface of a leaky mode device.

At step1030, the computing device may receive as input a view position.

At step1040, the computing device may direct an input strobe at a first time and thereby illuminate the SAW. The pulse timing may be computed based on a pattern and/or design of structures in the leaky mode device, and based on other features of the leaky mode device, such that the light pulse results in leaky mode light that interacts with the structures, which divide the leaky mode light into orders such that at least one order is directed toward the view position.

At step1050, the computing device may direct an input light to strobe at a second time such that one of the resulting orders is directed toward a second view position, and represents the virtual point as if at the same perceived actual location as perceived at the first view position.

As shown inFIG. 11, another exemplary method may comprise using an SMLMD to increase a view area.

At step1110, a computing device may generate or receive data comprising a representation of a set of virtual points.

At step1120, the computing device may transmit the data representation virtual point to a transducer, which may encode the virtual point as a first SAW that propagates across the surface of a leaky mode device.

At step1130, the computing device may direct an input light to strobe at a first time and thereby illuminate the first SAW. The pulse timing may be computed based on a pattern and/or design of structures in the leaky mode device, and based on other features of the leaky mode device, such that the light pulse results in leaky mode light that interacts with the structures, which divide the leaky mode light into orders such that at least one order is directed toward the view position.

At step1140, the computing device may transmit the data representation of a second virtual point to a transducer, which may encode the virtual point as a second SAW that propagates across the surface of the leaky mode device.

At step1150, the computing device may direct an input light to strobe at a second time and thereby illuminate the second SAW. The pulse timing may be computed based on a pattern and/or design of structures in the leaky mode device, and based on other features of the leaky mode device, such that the light pulse results in leaky mode light that interacts with the structures, which divide the leaky mode light into orders such that at least one order is directed toward the same view position.

The method steps disclosed above may be performed in different orders, or with some steps omitted, or other steps added, and remain within the scope of the disclosure herein.