Foveated near to eye display system using a computational freeform lens via spatial light modulation of a laser projected image onto an emissive film

A projection system projects images onto a projection surface in, for example, a computer game head-mounted display (HMD). The light is projected through a spatial light modulator that is combined with a Freeform Fourier Lens that is a combination of a Fresnel lens, an X-phase grating, a Y-phase grating, and a radial grating. The freeform lens causes the gradual shrinking of portions of the laser-projected image, decreasing the perceived pixel pitch in at least one foveal area on the projection surface compared to a non-modulated laser image. The center positions of the Fresnel lens and radial grating can be changed in the X and Y axes, moving the condensed foveal areas in accordance with eye tracking of the user. In effect, the system projects a Foveated image that contains variable pixel pitch such that a user perceives a higher visual acuity in his gaze direction.

FIELD

The application relates generally to foveated near to eye display systems using a computational freeform lens via spatial light modulation of a laser projected image onto an emissive film.

BACKGROUND

As recognized herein, for some laser projection applications such as head mounted displays (HMD) for computer games for augmented reality (AR) and/or virtual reality (VR), to enhance the user experience, it is desirable to present high acuity of images.

SUMMARY

As also understood herein, the resolution of the laser can be relaxed while still providing high acuity images for a wide field of view AR/VR system by matching the projection system to the visual acuity mapping of the human eye, thereby efficiently using projection pixels, bandwidth and the light sources.

Accordingly, in some example embodiments a projection system such as a laser liquid crystal on silicon (LCOS) or scanning laser projects an image with a large depth of field (focus free image) onto a spatial light modulator such as a reflective LCOS that is altered by a phase-only image of a Freeform Fourier Lens. The Freeform Fourier lens, which may be implemented in software, can be a combination of a Fresnel lens, an X-phase grating, a Y-phase grating, and a radial grating, with a center that can be adjusted within the entire phase image. The freeform lens causes the gradual shrinking of the laser-projected image around one or more areas within the image, decreasing the perceived pixel pitch in at least one foveal area on the projection surface compared to a non-modulated laser image. The center positions of the Fresnel lens and radial grating can be changed in the X and Y axes, moving the condensed image center within the total projected area defined by the laser image on the projection surface. The gratings and/or lens can be dynamically adjusted to steer the center of the condensed image around based on a user's eye gaze onto the projected surface. Additionally, the freeform lens may adjust the focus of the projected image on projection surface.

In addition to the lens with gratings, keystone correction/adjustment lenses/gratings can be applied to distort the projected image to the projection surface. Alternatively, other forms of distortion correction (barrel distortion correction, etc.) can be applied instead of or in addition to keystone correction, which will allow for projection onto curved or other non-flat surfaces. As used herein, “distortion/adjustment assembly” refers to keystone adjustment, barrel distortion correction, and other forms of distortion correction.

In effect, the system projects a Foveated image that contains variable pixel pitch such that a user perceives a higher visual acuity in his gaze direction to the projected surface without requiring the laser projector to have increased resolution. Thus, the projection system can more closely match the visual acuity mapping of the human eye and be more efficient at using projection pixels, bandwidth and the light sources.

An example projection surface can be a phosphor based emissive display, that when excited by one wavelength of light such as ultra-violet (UV) produces another wavelength. Such a system would provide a wide field of view (FOY) image with very large viewing angles and therefore a large eye-box. Alternatively, the projection surface can be a diffuse or reflective screen or an optical combiner such as a beam splitter or a holographic optical element. These are non-limiting examples of projector surfaces and optical combiners.

Accordingly, an apparatus includes a projection system configured to project an image onto a projection surface through a spatial light modulator operably associated with a phase-only image of a Freeform Fourier Lens FFL). The FFL can include a Fresnel lens, an X-phase grating, a Y-phase grating, and a radial grating. The FFL causes gradual shrinking of portions of the images from the projection system, decreasing perceived pixel pitch in at least one foveal area on the projection surface. The gratings can be configured to move a condensed image center within the image based on a user's eye gaze onto the projection surface.

It should be noted that a single apparatus may be provided for a display monitor application in, for instance, a laptop or personal computer or two apparatus may be provided (one for the left eye and one for the right eye) in a stereoscopic application such as a virtual reality or augmented reality head-mounted display (HMD).

In some examples, the projection system and spatial light modulator are supported in a head-mounted display (HMD). Other non-limiting examples of devices that can incorporate the projection system and spatial light modulator include laptop computers, personal computer displays, and other displays typically looked at by only a single person.

In example embodiments, at least one distortion/adjustment assembly is configured to distort the image projected to the projection surface in accordance with a shape of the projection surface.

In some embodiments, the projection surface includes a phosphor-based emissive display, that when excited by one wavelength of light produces another wavelength of light. In other embodiments, the projection surface includes a diffuse screen or a reflective screen, or an optical combiner. The projection system may include a liquid crystal on silicon device (LCOS), Digital Micro mirror Device (DMD), Digital Light Processing (DLP), Liquid Crystal Display (LCD), Micro-Electro Mechanical System (MEMS), or any other form of light modulator. The projection system may use laser or other forms of light sources like a narrow band LED. Alternatively, the projection system may consist of a back lit or edge lit Liquid Crystal Display (LCD), Organic Light-Emitting Diode display (OLED), Micro Light-Emitting Diode display (Micro-LED, mLED, uLED) or any other light emitting device. Optionally, the projection system can include projection optics to adjust the projected image to impinge onto the spatial light modulator. The projection optics can include Aspheric lenses, Fresnel Lenses, Thin-Film Lenses, Holographic Optical Elements or any form of optical device to adjust the projected image to the active area of the spatial light modulator.

In another aspect, a method includes identifying a direction of a user's gaze, and projecting, onto a projection surface, a Foveated image that contains variable pixel pitch with a higher visual acuity in a central portion of the image than in peripheral portions of the image. The method also includes moving the central portion of the image according to the direction of a use's gaze.

In another aspect, an assembly includes at least one projection surface, at least one projection system configured to direct light representing demanded images onto the projection surface, and at least one spatial light modulator interposed in an optical path between the projector and the projection surface to reflect light from the projector onto the projection surface. The assembly further includes a least one processor configured with instructions to send phase information to the spatial light modulator according to information from an eye tracking module indicating a gaze pose of a user.

The details of the present application, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:

DETAILED DESCRIPTION

This disclosure relates generally to computer ecosystems including aspects of consumer electronics (CE) device networks such as but not limited to computer game networks. A system herein may include server and client components, connected over a network such that data may be exchanged between the client and server components. The client components may include one or more computing devices including game consoles such as Sony PlayStation® or a game console made by Microsoft or Nintendo or other manufacturer of virtual reality (VR) headsets, augmented reality (AR) headsets, portable televisions (e.g. smart TVs, Internet-enabled TVs), portable computers such as laptops and tablet computers, and other mobile devices including smart phones and additional examples discussed below. These client devices may operate with a variety of operating environments. For example, some of the client computers may employ, as examples, Linux operating systems, operating systems from Microsoft, or a Unix operating system, or operating systems produced by Apple Computer or Google. These operating environments may be used to execute one or more browsing programs, such as a browser made by Microsoft or Google or Mozilla or other browser programs that can access websites hosted by the Internet servers discussed below. Also, an operating environment according to present principles may be used to execute one or more computer game programs.

Servers and/or gateways may include one or more processors executing instructions that configure the servers to receive and transmit data over a network such as the Internet. Or, a client and server can be connected over a local intranet or a virtual private network server or controller may be instantiated by a game console such as a Sony PlayStation®, a personal computer, etc.

A processor may be any conventional general-purpose single- or multi-chip processor that can execute logic by means of various lines such as address lines, data lines, and control lines and registers and shift registers.

Software modules described by way of the flow charts and user interfaces herein can include various sub-routines, procedures, etc. Without limiting the disclosure, logic stated to be executed by a particular module can be redistributed to other software modules and/or combined together in a single module and/or made available in a shareable library.

Further to what has been alluded to above, logical blocks, modules, and circuits described below can be implemented or performed with a general-purpose processor, a digital signal processor (DSP), a field programmable gate array (FPGA) or other programmable logic device such as an application specific integrated circuit (ASIC), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor can be implemented by a controller or state machine or a combination of computing devices.

FIG. 1illustrates a system10in which a projector system12such as a laser, or a light emitting diode (LED)-based projection system or a scanning laser, or a laser liquid crystal on silicon (LCOS), or other suitable projection system transmits light according to demanded images towards a spatial light modulator14. The spatial light modulator14can implement a phase-only image of a Freeform Fourier Lens (FFL), to be described further shortly. The spatial light modulator14reflects light toward a projection surface16that may be implemented by a phosphor-based emissive display that when excited by one wavelength of light produces another wavelength of light. Or, the projection surface16may be implemented by a diffuse screen or a reflective screen or an optical combiner or combination thereof.

In the example shown, a distortion/adjustment assembly18such as the above-mentioned keystone adjustment assembly may be interposed in the optical path between the spatial light modulator14and the projection surface16to correct for an oblique angle of projection and/or non-flat configurations of the projection surface16. For example, the distortion/adjustment assembly18may include one or more lenses, scanning mirrors, prisms, etc. The distortion/adjustment assembly is configured, based on a known projection angles, the curvature or other non-flat configuration of the projection surface16, to distort the projected image to the projection surface to ensure the projected image appears (without distortion) correct to a user viewing the projection surface.

An eye tracking module20sends user gaze pose information (the direction the user is looking, i.e., information pertaining to what portion of the projection surface16the user is focusing on) to a processor22accessing instructions and information from one or more computer storages24. The present assignee's U.S. patent application Ser. No. 16/012,022, filed Jun. 19, 2018 and incorporated herein by reference describe details of an example eye tracking module20, it being understood that present principles are not limited to any particular eye tracking device.

FIG. 1indicates that the processor22executes a software-implemented FFL26that outputs phase information to the spatial light modulator14according to user gaze pose information from the eye tracking module20such that the spatial light modulator14is modified to decrease perceived pixel pitch at the location of the projection surface16at which the user is looking.FIG. 2illustrates in graphical form an 8-bit phase image sent from the FFL26to the spatial light modulator14.

As shown inFIG. 1, the FFL26includes a Fresnel lens28, X-phase and Y-phase gratings30,32, which may be blaze gratings, and a radial grating34.FIGS. 3-5respectively illustrate in graphical form 8-bit phase data output by the Fresnel lens28, the x-phase grating30, and the y-phase grating32.

In addition to the above disclosure, the FFL26causes gradual shrinking of a portion of images from the projection system12to configure the spatial light modulator14for decreasing perceived pixel pitch in at least one foveal area on the projection surface, with the gratings30,32,34being configurable to move a condensed image center within the image based on a user's eye gaze onto the projection surface16. In an example, the gratings30,32,34may be implemented by respective phase images.

FIG. 6shows a system200that in all essential respects is identical to the system10shown inFIG. 1in configuration and operation, with like components sharing like reference numerals, with the following exceptions. Instead of a hardware-implemented keystone adjustment assembly, the system200uses a software-based distortion/adjustment assembly that includes a software-implemented x-dimension distortion/adjustment module202and a software-implemented y-dimension distortion/adjustment module204that are configured to alter information sent to the spatial light modulator14as appropriate to correct for or otherwise accommodate the projection angle and/or non-flat surface portions in the projection surface18.

FIG. 7shows a simplified flow chart of example overall logic consistent with present principles. Commencing at block300, the eye tracking information from the eye tracking module20is received. Moving to block302, demanded images are received, e.g., from a computer game console. Proceeding to block304, the gratings30,32are configured to alter the phase output of the freeform lens28to the spatial light modulator14such that the smallest pixel pitch is focused on the region of the projection surface16at which the user is directing his gaze. Block306indicates that responsive to the demanded images the projection system12projects light onto the projection surface18by transmitting light to the spatial light modulator14, which reflects the light to the projection surface16in accordance with the phase information from the FFL26.

FIG. 8shows a head-mounted display208with lenses210and at least one eye tracking22sat least one laser light source assembly222positioned to illuminate the eye, reflections of which impinge upon the assembly220for eye tracking purposes. The present assignee's U.S. patent application Ser. No. 16/012,022, filed Jun. 19, 2018 and incorporated herein by reference describe details of the assemblies220,222.

A projection system230(embedded in the HMD device208) such as the one described above projects light onto a projection surface (within the HMD208, but not shown nFIG. 8) which are viewed by the lenses210, with the image on the projection surface being adjusted by the spatial light modulator232(also embedded in the HMD device208) such as the one described above according to the eye tracking provided by the assemblies220,222. Thus, the projection systems and FFLs described herein may be supported in a head-mounted display (HMD).

Now referring toFIG. 9, an example system1400is shown, which may include one or more of the example devices mentioned below in accordance with present principles. The first of the example devices included in the system1410is a consumer electronics (CE) device such as an audio video device (AVD)1412such as but not limited to an Internet-enabled TV with a TV tuner (equivalently, set top box controlling a TV). However, the AVD1412alternatively may be an appliance or household item, e.g. computerized Internet enabled refrigerator, washer, or dryer. The AVD1412alternatively may also be a computerized Internet enabled (“smart”) telephone, a tablet computer, a notebook computer, a wearable computerized device such as e.g. computerized Internet-enabled watch, a computerized Internet-enabled bracelet, other computerized Internet-enabled devices, a computerized Internet-enabled music player, computerized Internet-enabled head phones, a computerized Internet-enabled implantable device such as an implantable skin device, etc. Regardless, it is to be understood that the AVD1412is configured to undertake present principles (e.g. communicate with other CE devices to undertake present principles, execute the logic described herein, and perform any other functions and/or operations described herein).

Accordingly, to undertake such principles the AVD1412can be established by some or all of the components shown inFIG. 9. For example, the AVD1412can include one or more displays1414that may be implemented by a high definition or ultra-high definition “4K” or higher flat screen and that may be touch-enabled for receiving user input signals via touches on the display. The AVD1412may include one or more speakers1416for outputting audio in accordance with present principles, and at least one additional input device1418such as e.g. an audio receiver/microphone for e.g. entering audible commands to the AVD1412to control the AVD1412. The example AVD1412may also include one or more network interfaces1420for communication over at least one network1422such as the Internet, an WAN, an LAN, etc. under control of one or more processors1424including. A graphics processor1424A may also be included. Thus, the interface1420may be, without limitation, a Wi-Fi transceiver, which is an example of a wireless computer network interface, such as but not limited to a mesh network transceiver. It is to be understood that the processor1424controls the AVD1412to undertake present principles, including the other elements of the AVD1412described herein such as e.g. controlling the display1414to present images thereon and receiving input therefrom. Furthermore, note the network interface1420may be, e.g., a wired or wireless modern or router, or other appropriate interface such as, e.g., a wireless telephony transceiver, or transceiver as mentioned above, etc.

In addition to the foregoing, the AVD1412may also include one or more input ports1426such as, e.g., a high definition multimedia interface (HDMI) port or a USB port, to physically connect (e.g. using a wired connection) to another CE device and/or a headphone port to connect headphones to the AVD1412for presentation of audio from the AVD1412to a user through the headphones. For example, the input port1426may be connected via wire or wirelessly to a cable or satellite source1426aof audio video content. Thus, the source1426amay be, e.g., a separate or integrated set top box, or a satellite receiver. Or, the source1426amay be a game console or disk player containing content that might be regarded by a user as a favorite for channel assignation purposes described further below. The source1426awhen implemented as a game console may include some or all of the components described below in relation to the CE device1444.

The AVD1412may further include one or more computer memories1428such as disk-based or solid-state storage that are not transitory signals, in some cases embodied in the chassis of the AVD as standalone devices or as a personal video recording device (PVR) or video disk player either internal or external to the chassis of the AVD for playing back AV programs or as removable memory media. Also, in some embodiments, the AVD1412can include a position or location receiver such as but not limited to a cellphone receiver, GPS receiver and/or altimeter1430that is configured to e.g. receive geographic position information from at least one satellite or cellphone tower and provide the information to the processor1424and/or determine an altitude at which the AVD1412is disposed in conjunction with the processor1424. However, it is to be understood that that another suitable position receiver other than a cellphone receiver, GPS receiver and/or altimeter may be used in accordance with present principles to e.g. determine the location of the AVD1412in e.g. all three dimensions.

Continuing the description of the AVD1412, in some embodiments the AVD1412may include one or more cameras1432that may be, e.g., a thermal imaging camera, a digital camera such as a webcam, and/or a camera integrated into the AVD1412and controllable by the processor1424to gather pictures/images and/or video in accordance with present principles. Also included on the AVD1412may be a Bluetooth transceiver1434and other Near Field. Communication (NFC) element1436for communication with other devices using Bluetooth and/or NFC technology, respectively. An example NFC element can be a radio frequency identification (RFID) element.

Further still, the AVD1412may include one or more auxiliary sensors1437(e.g., a motion sensor such as an accelerometer, gyroscope, cyclometer, or a magnetic sensor, an infrared (IR) sensor, an optical sensor, a speed and/or cadence sensor, a gesture sensor (e.g. for sensing gesture command), etc.) providing input to the processor1424. The AVD1412may include an over-the-air TV broadcast port1438for receiving OTA TV broadcasts providing input to the processor1424. In addition to the foregoing, it is noted that the AVD1412may also include an infrared (IR) transmitter and/or IR receiver and/or IR transceiver1442such as an IR data association (IRDA) device. A battery (not shown) may be provided for powering the AVD1412.

Still referring toFIG. 9, in addition to the AVD1412, the system1400may include one or more other CE device types. In one example, a first CE device1444may be used to send computer game audio and video to the AVD1412via commands sent directly to the AVD1412and/or through the below-described server while a second CE device1446may include similar components as the first CE device1444. In the example shown, the second CE device1446may be configured as a VR headset worn by a player1447as shown. In the example shown, only two CE devices1444,1446are shown, it being understood that fewer or greater devices may be used. For example, principles below discuss multiple players1447with respective headsets communicating with each other during play of a computer game sourced by a game console to one or more AVD1412, as an example of a multiuser voice chat system.

In the example shown, to illustrate present principles all three devices1412,1444,1446are assumed to be members of an entertainment network in, e.g., a home, or at least to be present in proximity to each other in a location such as a house. However, present principles are not limited to a particular location, illustrated by dashed lines1448, unless explicitly claimed otherwise. Any or all of the devices inFIG. 9can implement any one or more of the lasers, etc. described previously.

The example non-limiting first CE device1444may be established by any one of the above-mentioned devices, for example, a portable wireless laptop computer or notebook computer or game controller (also referred to as “console”), and accordingly may have one or more of the components described below. The first CE device1444may be a remote control (RC) for, e.g., issuing AV play and pause commands to the AVD1412, or it may be a more sophisticated device such as a tablet computer, a game controller communicating via wired or wireless link with the AVD1412, a personal computer, a wireless telephone, etc.

Accordingly, the first CE device1444may include one or more displays1450that may be touch-enabled for receiving user input signals via touches on the display. The first CE device1444may include one or more speakers1452for outputting audio in accordance with present principles, and at least one additional input device1454such as e.g. an audio receiver/microphone for e.g. entering audible commands to the first CE device1444to control the device1444. The example first CE device1444may also include one or more network interfaces1456for communication over the network1422under control of one or more CE device processors1458. A graphics processor1458A may also be included. Thus, the interface1456may be, without limitation, a Wi-Fi transceiver, which is an example of a wireless computer network interface, including mesh network interfaces. It is to be understood that the processor1458controls the first CE device1444to undertake present principles, including the other elements of the first CE device1444described herein such as e.g. controlling the display1450to present images thereon and receiving input therefrom. Furthermore, note the network interface1456may be, e.g., a wired or wireless modem or router, or other appropriate interface such as, e.g., a wireless telephony transceiver, or Wi-Fi transceiver as mentioned above, etc.

In addition to the foregoing, the first CE device1444may also include one or more input ports1460such as, e.g., a HDMI port or a USB port to physically connect (e.g. using a wired connection) to another CE device and/or a headphone port to connect headphones to the first CE device1444for presentation of audio from the first CE device1444to a user through the headphones. The first CE device1444may further include one or more tangible computer readable storage medium1462such as disk-based or solid-state storage. Also in some embodiments, the first CE device1444can include a position or location receiver such as but not limited to a cellphone and/or GPS receiver and/or altimeter1464that is configured to e.g. receive geographic position information from at least one satellite and/or cell tower, using triangulation, and provide the information to the CE device processor1458and/or determine an altitude at which the first CE device1444is disposed in conjunction with the CE device processor1458. However, it is to be understood that that another suitable position receiver other than a cellphone and/or GPS receiver and/or altimeter may be used in accordance with present principles to e.g. determine the location of the first CE device1444in e.g. all three dimensions.

Continuing the description of the first CE device1444, in some embodiments the first CE device1444may include one or more cameras1466that may be, e.g., a thermal imaging camera, a digital camera such as a webcam, and/or a camera integrated into the first CE device1444and controllable by the CE device processor1458to gather pictures/images and/or video in accordance with present principles. Also included on the first CE device1444may be a Bluetooth transceiver1468and other Near Field Communication (NFC) element1470for communication with other devices using Bluetooth and/or NFC technology, respectively. An example NFC element can be a radio frequency identification (RFID) element.

Further still, the first CE device1444may include one or more auxiliary sensors1472(e.g., a motion sensor such as an accelerometer, gyroscope, cyclometer, or a magnetic sensor, an infrared (IR) sensor, an optical sensor, a speed and/or cadence sensor, a gesture sensor (e.g. for sensing gesture command), etc.) providing input to the CE device processor1458. The first CE device1444may include still other sensors such as e.g. one or more climate sensors1474(e.g. barometers, humidity sensors, wind sensors, light sensors, temperature sensors, etc.) and/or one or more biometric sensors1476providing input to the CE device processor1458. In addition to the foregoing, it is noted that in some embodiments the first CE device1444may also include an infrared (IR) transmitter and/or IR receiver and/or IR transceiver1478such as an IR data association (IRDA) device. A battery (not shown) may be provided for powering the first CE device1444. The CE device1444may communicate with the AVD1412through any of the above-described communication modes and related components.

The second CE device1446may include some or all of the components shown for the CE device1444. Either one or both CE devices may be powered by one or more batteries.

Now in reference to the afore-mentioned at least one server1480, it includes at least one server processor1482, at least one tangible computer readable storage medium1484such as disk-based or solid state storage, and at least one network interface1486that, under control of the server processor1482, allows for communication with the other devices ofFIG. 9over the network1422, and indeed may facilitate communication between servers and client devices in accordance with present principles. Note that the network interface1486may be, e.g., a wired or wireless modem or router, Wi-Fi transceiver, or other appropriate interface such as, e.g., a wireless telephony transceiver.

Accordingly, in some embodiments the server1480may be an Internet server or an entire server “farm” and may include and perform “cloud” functions such that the devices of the system1400may access a “cloud” environment via the server1480in example embodiments for, e.g., network gaming applications. Or, the server1480may be implemented by one or more game consoles or other computers in the same room as the other devices shown inFIG. 9or nearby.

The methods herein may be implemented as software instructions executed by a processor, suitably configured application specific integrated circuits (ASIC) or field programmable gate array (FPGA) modules, or any other convenient manner as would be appreciated by those skilled in those art. Where employed, the software instructions may be embodied in a non-transitory device such as a CD ROM or Flash drive. The software code instructions may alternatively be embodied in a transitory arrangement such as a radio or optical signal, or via a download over the internet.

It will be appreciated that whilst present principals have been described with reference to some example embodiments, these are not intended to be limiting, and that various alternative arrangements may be used to implement the subject matter claimed herein.