Multi-channel scanner for near-eye display

Abstract

Disclosed is a multi-channel scanner that can be used, for example, in a near-eye display. The multi-channel scanner scans a light beam angularly to form an image in an angular domain. The multi-channel scanner includes a light source, a tiltable reflector, and a multi-channel coupler that couples the light emitted by the light source to the tiltable reflector, receives the reflected light, and couples it back to the tiltable reflector to double the scanning angle. Then, the multi-channel coupler couples the light reflected from the tiltable reflector at least twice to the exit pupil of the scanner. A pupil replication waveguide disposed at the exit pupil of the scanner expands the image in the angular domain. Multiple reflections of the light beam from the tiltable reflector can increase the angular scanning range of the display and the associated field of view without increasing the angular scanning range of the tiltable reflector.

Description

Technical Field

[0001] The present disclosure relates to wearable head-mounted devices, and more particularly to components and modules for wearable visual display head-mounted devices. Background Art

[0002] Head-mounted displays (HMDs), helmet-mounted displays, near-eye displays (NEDs), etc. are increasingly being used to display virtual reality (VR) content, augmented reality (AR) content, mixed reality (MR) content, etc. To name just a few examples, such displays are used in different fields including entertainment, education, training, and biomedical science. The VR / AR / MR content displayed can be three-dimensional (3D) to enhance the experience and match virtual objects with real objects observed by the user. The user's eye position and gaze direction and / or orientation can be tracked in real time, and the displayed image can be dynamically adjusted according to the user's head direction and gaze direction to provide a better immersive experience in a simulated or enhanced environment.

[0003] Head-mounted displays require compact display devices. Since the displays of HMDs or NEDs are typically worn on the user's head, large, bulky, unbalanced, and / or heavy display devices would be cumbersome and may be uncomfortable for the user to wear.

[0004] Projector-based displays (e.g., scanned projector displays) provide angular field images that can be directly observed by the user's eyes without an intermediate screen or display panel. Pupil replication waveguides are used to deliver the angular field images to the user's eyes. The absence of a screen or display panel in a scanned projector display enables the reduction of the size and weight of the display. Images can be obtained by scanning a light beam over the field of view (FOV) of the display. Summary of the Invention

[0005] Scanned projector displays require an optical scanner, which is typically based on a tiltable reflector. The scanner should be able to scan a light beam over the entire field of view (FOV) of the display. When the light beam is scanned, its brightness and / or color can be changed in coordination with the scan to provide an angular field image. The light beam can be scanned in two directions, e.g., in the X and Y viewing angles. When the frame rate is high enough, the eye integrates the scanned light beam such that the user can see the displayed image with substantially no flicker.

[0006] One challenge in constructing a scanning display with a tiltable reflector is the angular scan range required for the tiltable reflector. A large scan range requires a trade-off with other parameters, including bending stiffness and scan rate (frequency). A thin and flexible hinge cannot support a larger mirror required to provide the desired beam size and image quality. According to the present disclosure, the beam can be incident on the same tiltable reflector multiple times, thereby increasing the scan range without having to increase the maximum tilt angle of the reflector.

[0007] The present invention relates to a multi-channel scanner for scanning a beam of light and a near-eye display for providing an image in an angular field at an eye box.

[0008] According to the present disclosure, there is provided a multi-channel scanner for scanning a beam of light. The multi-channel scanner includes: a light source for providing a beam of light; a tiltable reflector for reflecting the beam of light provided by the light source by tilting the tiltable reflector at a variable angle; and a multi-channel coupler for receiving the beam of light from the light source and coupling the beam of light to the tiltable reflector; for receiving the beam of light reflected from the tiltable reflector for the first time at twice the variable angle and redirecting the beam of light back to the tiltable reflector; and for receiving the beam of light reflected from the tiltable reflector for the second time and coupling the beam of light to an exit pupil of the multi-channel scanner.

[0009] The multi-channel coupler may include: a reflective polarizer for reflecting light having a first polarization state and transmitting light having a second polarization state, the second polarization state being orthogonal to the first polarization state; and a first quarter-wave plate (QWP) disposed in an optical path between the reflective polarizer and the tiltable reflector and configured to convert the polarization state of light between the first polarization state and the second polarization state after double-channel propagation through the first QWP. In operation, a beam of light having the second polarization state sequentially propagates through the reflective polarizer and the first QWP, strikes the tiltable reflector for the first time, is reflected by the tiltable reflector to again propagate through the first QWP, thereby converting to the first polarization state, is reflected by the reflective polarizer, propagates through the first QWP and strikes the tiltable reflector for the second time, is reflected by the tiltable reflector to propagate through the first QWP, thereby converting back to the second polarization state, and propagates through the reflective polarizer to the exit pupil.

[0010] The multi-channel coupler may include a first lens element having positive optical power and including a convex surface proximate to a tiltable reflector, the convex surface supporting a reflective polarizer. Optionally, the multi-channel coupler may further include a second lens element disposed between the first lens element and the exit pupil. In operation, the light beam provided by the light source then propagates successively through the second lens element, through the first lens element, impinges on the tiltable reflector, is reflected by the reflective polarizer to impinge on the tiltable reflector a second time and is reflected by the tiltable reflector, propagates through the first lens element, propagates through the second lens element, and impinges on the exit pupil of the multi-channel coupler. In some embodiments, the second lens element may include: a first coaxial optical surface and a second coaxial optical surface, the first optical surface facing the first lens element; a side surface, between the first optical surface and the second optical surface, for inputting the light beam provided by the light source into the second lens element; and a buried steering mirror, within the second lens element in the optical path of the light beam input through the side surface of the second lens element, for steering the light beam to the first optical surface of the second lens element.

[0011] In some embodiments, a multi-channel scanner may include: a polarization beam splitter (PBS) configured to reflect light having a first polarization state and transmit light having a second polarization state. A first curved reflector and a second curved reflector may be disposed on adjacent surfaces proximate the PBS and configured to reflect a light beam exiting the PBS back to the PBS, wherein the first curved reflector and the reflective polarizer are disposed on opposite sides of the PBS, and wherein the second curved reflector and the tiltable reflector are disposed on opposite sides of the PBS. A second QWP may be disposed in the optical path between the PBS and the first curved reflector and configured to convert the polarization state of light between the first polarization state and the second polarization state during two-channel propagation through the second QWP. A third QWP may be disposed in the optical path between the PBS and the second curved reflector and configured to convert the polarization state of light between the first polarization state and the second polarization state during two-channel propagation through the second QWP. In operation, a light beam provided by a light source may propagate sequentially as follows: through an opening in the first curved reflector, through the second QWP, while in the first polarization state, impinge on the PBS, be reflected by the PBS towards the tiltable reflector, propagate through the first QWP, be first reflected by the tiltable reflector, propagate again through the first QWP, thereby converting to the second polarization state, propagate through the PBS and the third QWP, impinge on the second curved reflector, propagate again through the third QWP, thereby converting to the first polarization state, and be reflected by the PBS towards the reflective polarizer. In the first polarization state, the light beam reflected by the PBS towards the reflective polarizer may optionally propagate back to the PBS, be reflected by the PBS towards the second curved reflector, propagate through the third QWP, be reflected by the second curved reflector to propagate again through the third QWP, thereby converting to the second polarization state, propagate through the PBS, through the first QWP, and be reflected by the tiltable reflector a second time towards the PBS. The light beam reflected a second time by the tiltable reflector may optionally propagate again through the first QWP, thereby converting to the first polarization state, be reflected by the PBS towards the first curved reflector, propagate through the second QWP, be reflected by the first curved reflector, propagate again through the second QWP, thereby converting to the second polarization state, propagate through the PBS, and propagate through the reflective polarizer to the exit pupil.

[0012] In some embodiments, the multi-channel scanner may further include a first lens element in the optical path between the PBS and the tiltable reflector, and a second lens element in the optical path between the PBS and the reflective polarizer. In some embodiments, the multi-channel coupler includes a first coupler portion for coupling the light provided by the light source to the tiltable reflector, and the multi-channel coupler may include a reflector for reflecting the light from the tiltable reflector back to the tiltable reflector. The multi-channel coupler may further include a second coupler portion, the second coupler portion including a pupil auto-relay for relaying the light reflected by the tiltable reflector back to the tiltable reflector for the first time, and the multi-channel coupler may optionally include a third coupler portion for relaying the light reflected by the tiltable reflector for the second time to the exit pupil of the multi-channel scanner.

[0013] According to the present disclosure, there is provided a near-eye display for providing an angular field image at an eye box. The near-eye display includes: a light source for providing a light beam; a tiltable reflector for reflecting the light beam provided by the light source by tilting the tiltable reflector at a variable angle; a pupil replication waveguide for receiving the light beam tilted by the tiltable reflector and expanding the light beam above the eye box by providing multiple portions of the light beam above the eye box; and a multi-channel coupler for receiving the light beam from the light source and coupling the light beam to the tiltable reflector; for receiving the light beam reflected from the tiltable reflector for the first time at twice the variable angle and redirecting the light beam back to the tiltable reflector; and for receiving the light beam reflected from the tiltable reflector for the second time and coupling the light beam to the pupil replication waveguide.

[0014] In embodiments where the light source and the multi-channel coupler are disposed on opposite sides of the pupil replication waveguide, the pupil replication waveguide may include an opening therein for propagating the light beam provided by the light source for coupling to the multi-channel coupler. The tiltable reflector may include a tiltable microelectromechanical system (MEMS) reflector. The multi-channel coupler may include a pupil auto-relay for relaying the light reflected by the tiltable reflector back to the tiltable reflector for the first time.

[0015] According to the present disclosure, there is also provided a near-eye display for providing angular field images at an eye box. The near-eye display includes: a first light source for providing a first light beam; a second light source for providing a second light beam; a tiltable reflector for reflecting the first light beam and the second light beam at variable angles; a pupil replication waveguide for receiving the first light beam and the second light beam tilted by the tiltable reflector and expanding the first light beam and the second light beam above the eye box by providing multiple portions of the first light beam and the second light beam above the eye box. The pupil replication waveguide includes a polarization-selective inner coupler for inner-coupling light in a first polarization state while transmitting light in a second polarization state orthogonal to the first polarization state. The near-eye display further includes a pupil replication waveguide for receiving the light beam tilted by the tiltable reflector and expanding the light beam above the eye box by providing multiple portions of the light beam to the eye box; and a multi-channel coupler for receiving the light beam from the light source and coupling the light beam to the tiltable reflector; for receiving the light beam reflected from the tiltable reflector at a first variable angle twice and redirecting the light beam back to the tiltable reflector; and for receiving the light beam reflected from the tiltable reflector a second time and coupling the light beam to the pupil replication waveguide. The first light source and the second light source may be arranged on opposite sides of the pupil replication waveguide from the first curved reflector and the second curved reflector.

[0016] In an embodiment where the first light source and the second light source and the first and second curved reflectors are arranged on the same side of the pupil replication waveguide, the near-eye display may further include a first folding mirror in the optical path between the first light source and the first curved reflector; and a second folding mirror in the optical path between the second light source and the second curved reflector.

[0017] Furthermore, the present invention relates to a near-eye display for providing angular field images at an eye box having the near-eye display, including:

[0018] - a first light source for providing a first light beam;

[0019] - a second light source for providing a second light beam;

[0020] - a tiltable reflector for reflecting the first light beam and the second light beam at variable angles;

[0021] - a pupil replication waveguide for receiving the first light beam and the second light beam tilted by the tiltable reflector and expanding the first light beam and the second light beam above the eye box by providing multiple portions of the first light beam and the second light beam above the eye box, the pupil replication waveguide including a polarization-selective inner coupler for inner-coupling light in a first polarization state while transmitting light in a second polarization state orthogonal to the first polarization state;

[0022] - A first curved reflector for receiving a first light beam from a first light source and reflecting the first light beam in a second polarization state to a tiltable reflector and through a polarization-selective internal coupler; and

[0023] - A second curved reflector for receiving a second light beam from a second light source and reflecting the second light beam in a second polarization state to a tiltable reflector and through a polarization-selective internal coupler.

[0024] After being reflected from the tiltable reflector, the first light beam and the second light beam are in a first polarization state, whereby the first light beam and the second light beam are internally coupled into a pupil replication waveguide.

[0025] In one embodiment, the first light source and the second light source are arranged on opposite sides of the pupil replication waveguide from the first curved reflector and the second curved reflector. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Exemplary embodiments will now be described in conjunction with the drawings, wherein:

[0027] Figure 1 is a schematic block diagram of a near-eye display including a multi-channel scanner of the present disclosure;

[0028] Figure 2 is a schematic diagram of a polarization-based multi-channel coupler that uses polarization diversity to ensure double reflection of light beams from the same tiltable reflector;

[0029] Figure 3 is a three-dimensional view of an input coupler of a pupil replication waveguide, the input coupler including a small opening in the input coupler for propagating a light beam;

[0030] Figure 4A and Figure 4B is a ray tracing cross-sectional view of a near-eye display including a multi-channel scanner having a Figure 2 polarization configuration and an input coupler for a non-tilted ( Figure 4A ) and tilted ( Figure 4B ) tiltable reflector; Figure 3 of a near-eye display;

[0031] Figure 5A and Figure 5B is a ray tracing cross-sectional view of a near-eye display including a multi-channel scanner having a Figure 2 polarization configuration and including a small buried mirror for a non-tilted ( Figure 5A ) and tilted ( Figure 5B ) tiltable reflector;

[0032] Figures 6A to 6Dis a ray tracing cross-section of a near-eye display including a multi-channel scanner based on a polarization beam splitter (PBS), showing the following light propagation: from a light source to a tiltable reflector to a reflective polarizer ( Figure 6A ); from the reflective polarizer back to the tiltable reflector ( Figure 6B ); from the tiltable reflector back through the reflective polarizer and to the pupil replication waveguide ( Figure 6C ); and showing the entire folded optical path ( Figure 6D );

[0033] Figure 6E is Figures 6A to 6D a ray tracing cross-section of a near-eye display, showing the main ray propagation through the system;

[0034] Figure 7 is a schematic block diagram of an embodiment of a multi-channel scanner including a reflective polarizer for redirecting a reflected light beam back to a tiltable reflector;

[0035] Figure 8 is a schematic block diagram of an embodiment of a multi-channel scanner including a pupil auto-relay for redirecting a reflected light beam back to a tiltable reflector;

[0036] Figure 9A and Figure 9B are a ray tracing cross-section ( Figure 9A ) and a 3D wireframe ( Figure 9B ) of a near-eye display including a pair of curved reflectors for reflecting a light beam to a tiltable reflector through a pupil replication waveguide;

[0037] Figure 10A and Figure 10B are a ray tracing 3D solid diagram ( Figure 10A ) and a 3D wireframe ( Figure 10B ) of a near-eye display including four curved reflectors for reflecting a light beam to a tiltable reflector through a pupil replication waveguide;

[0038] Figure 11A and Figure 11B are a ray tracing cross-section of a near-eye display including a pair of curved reflectors for reflecting a light beam to a tiltable reflector and through a pupil replication waveguide, wherein for non-tilted ( Figure 11A ) and tilted ( Figure 11B ) tiltable reflectors, the light source and the curved reflectors are arranged on the same side of the pupil replication waveguide;

[0039] Figure 12A 、 Figure 12B and Figure 12C are front views of a multi-emitter light source available in the near-eye displays disclosed herein;

[0040] Figure 13A A graph showing the aspect ratio of the field of view (FOV) of a scanned projector display as a function of the beam tilt angle;

[0041] Figure 13B is Figure 13A A schematic diagram of the FOV at zero tilt angle in

[0042] Figure 13C is Figure 13A A schematic diagram of the FOV at non - zero tilt angle in

[0043] Figure 14A An isometric view of the head - mounted display device of the present disclosure;

[0044] Figure 14B is including Figure 14A A block diagram of a virtual reality system of a head - mounted device. Detailed implementation

[0045] Although the present teachings are described in connection with various embodiments and examples, it is not intended to limit the present teachings to these embodiments. On the contrary, those skilled in the art will understand that the teachings include various alternative forms and equivalent forms. All statements herein reciting the principles, aspects, and embodiments of the present disclosure, as well as specific examples thereof, are intended to encompass their structural and functional equivalents. In addition, such equivalent forms are intended to include both currently known equivalent forms and equivalent forms developed in the future, that is, any elements developed to perform the same function, regardless of structure.

[0046] As used herein, unless expressly stated otherwise, the terms "first", "second", etc. are not intended to imply an order of sequencing, but rather to distinguish one element from another. Similarly, unless expressly stated otherwise, the order of method steps does not imply the order in which they are performed. In Figures 1 - 3 , Figures 4A - 4B , Figures 5A - 5B , Figures 6A - 6E , Figure 7 , Figure 8 , Figures 9A - 9B , Figures 10A - 10B and Figures 11A - 11B similar reference numerals represent similar elements.

[0047] Referring to Figure 1 , the near - eye display 100 includes a multi - channel scanner 130 optically coupled to a pupil replication waveguide 136. The multi - channel scanner 130 can be used to provide an image to the pupil replication waveguide 136 in the angular domain by scanning a beam 102 of variable brightness and / or color over the FOV of the display. The beam 102 is emitted by a light source 104.

[0048] The multi-channel scanner 130 includes a tiltable reflector 106 for reflecting the light beam 102 provided by the reflection light source 102. The light beam 102 is scanned or directed by tilting the tiltable reflector 106 at a variable angle. The tiltable reflector 106 may include a microelectromechanical (MEMS) reflector that tilts at a controllable angle by applying a control signal to its electrodes. For example, the MEMS reflector may include a mirror and / or a grating. The multi-channel scanner 130 further includes a multi-channel coupler 140 configured to receive the light beam 102 from the light source 102 and couple the light beam 102 to the tiltable reflector 106. The multi-channel coupler 140 directs the light beam 102 to the tiltable reflector 106 and receives, for the first time (event 131), the light beam 102 reflected from the tiltable reflector 106 at twice the tilt angle of the tiltable reflector 106, and redirects the light beam 102 back to the tiltable reflector 106 for a second reflection. The portion 141 of the multi-channel coupler 140 that couples the light beam 102 back to the tiltable reflector 106 may include, for example, a mirror or a pupil auto-relay. Examples of both will be considered further below.

[0049] The multi-channel coupler 140 redirects the light beam 102 back to the tiltable reflector 106 and receives, for the second time (event 132), the light beam 102 reflected from the tiltable reflector at an increased angle that is four times the variable angle, and couples the light beam to the exit pupil 134 of the multi-channel scanner 130. The increased angle of the light beam 102 is due to multiple reflections from the tiltable reflector 106. A pupil replication waveguide 136 may be disposed near the exit pupil 134 for receiving the light beam at four times the variable tilt angle of the tiltable reflector 106. In some embodiments, the multi-channel coupler 140 has an optical magnification factor greater than or less than 1 between the light source 104 and the exit pupil 102, in which case the angle of the light beam 102 at the exit pupil 134 may be different from four times the tilt angle of the tiltable reflector 106, but is generally greater than the tilt angle of the tiltable reflector 106.

[0050] In some embodiments, the multi-channel coupler 140 may be configured based on polarization diversification to ensure double reflection of the light beam 102 from the tiltable mirror 106. Refer to Figure 2 , the multi-channel coupler 240 includes a reflective polarizer 208 for reflecting light having a first polarization state and transmitting light having a second polarization state that is orthogonal to the first polarization state. For example, the first polarization state and the second polarization state may be orthogonal linear polarization states or opposite circular polarization states.

[0051] A quarter-wave plate (QWP) 211 is disposed in the optical path between the reflective polarizer 208 and the tiltable reflector 106 and is configured to convert the polarization state of light between a first polarization state and a second polarization state during two-channel propagation through the QWP 211. In operation, a beam 102 having a second polarization state PS2 propagates sequentially through the pupil replication waveguide 136, through the reflective polarizer 208 and the QWP 211, impinges on the tiltable reflector 106, and is reflected by the tiltable reflector for the first time (event 231) to propagate again through the QWP 211, thereby converting to the first polarization state PS1, being reflected by the reflective polarizer 208, propagating through the QWP 211 and impinging on the tiltable reflector for the second time, and being reflected by the tiltable reflector for the second time (event 232) to propagate through the QWP 211, thereby converting back to the second polarization state PS2, and thus propagating through the reflective polarizer 208 towards the pupil replication waveguide 136, where it is internally coupled to propagate in the pupil replication waveguide 136.

[0052] It should be understood that, for illustration only, Figure 2 the beam 102 shown in is vertically separated. In an actual device, according to the law of reflection, the beam 102 can propagate along the same path to the tiltable reflector 106 at a normal angle of incidence and can deviate from the same path to the tiltable reflector 106 at a non-zero angle of incidence. An internal coupler, such as Figure 3 the grating internal coupler 342 shown, can be used to internally couple the beam 102 into the pupil replication waveguide 136. To ensure that the beam 102 is not internally coupled into the pupil replication waveguide 136 during the first incidence, the grating internal coupler 342 can include an aperture 343. The beam 102 can be focused on the aperture 343 to propagate through the grating internal coupler 342 with substantially no loss.

[0053] Now the implementation of Figure 2 the polarization-based multi-channel coupler 240 will be considered. Referring to Figure 4A and Figure 4B, the near-eye display 400 includes a multi-channel scanner 430 coupled to the pupil replication waveguide 136. The multi-channel scanner 430 includes a light source 404, a tiltable reflector 406, and a multi-channel coupler 440. The light source 404 is disposed on the pupil replication waveguide 136 opposite the tiltable reflector 406 and the multi-channel coupler 440. The multi-channel coupler 440 includes a first lens element 414 having positive optical power (i.e., focusing power). The first lens element 414 includes a convex surface near the tiltable reflector 406 and may include a concave opposite surface coaxial with the convex surface. The convex surface supports a reflective polarizer 408, and the reflective polarizer 408 may have the same shape as the convex surface of the first lens element 414. The QWP 411 is disposed between the reflective polarizer 408 and the tiltable reflector 406. The QWP 411 may be supported by a window of the housing (not shown) of the tiltable reflector 406 and may even be supported by the tiltable reflector 406 itself, or may be laminated to the reflective polarizer 408.

[0054] The multi-channel coupler 440 may further include a second lens element 416 disposed between the first lens element 414 and the exit pupil located near the pupil replication waveguide 136. In operation, the light source 404 provides a light beam 402 that converges onto an opening 343 in the input coupler 342 of the pupil replication waveguide 136 ( Figure 3 ). The light beam 402 ( Figure 4A and Figure 4B ) propagates through the opening 343 and couples into the multi-channel coupler 440. Then, the light beam 402 sequentially propagates through the second lens element 416, through the first lens element 414, impinges on the tiltable reflector 406 and is reflected by the tiltable reflector 406, is reflected by the reflective polarizer 408 to impinge on the tiltable reflector 406 a second time and is reflected by the tiltable reflector 406, propagates through the first lens element 414, propagates through the second lens element 416, and impinges on the exit pupil of the multi-channel scanner 430 located at the pupil replication waveguide. The surfaces of the first lens element 414 and the second lens element 416 may be optimized to provide the necessary collimation of the light beam 402 at the pupil replication waveguide 136. The above optical path is defined by the positions and orientations of the reflective polarizer 408 and the QWP 411 configured as described above with reference to Figure 2 .

[0055] Now turning to Figure 5A and Figure 5B, the near-eye display 500 includes a multi-channel scanner 530 coupled to a pupil replication waveguide 536. The multi-channel scanner 530 includes a light source 504, a tiltable reflector 506, and a multi-channel coupler 540. The light source 504, the tiltable reflector 506, and the multi-channel coupler 540 are arranged on the same side of the pupil replication waveguide 536. The multi-channel coupler 540 includes a first lens element 514 having a positive optical power. The first lens element 514 includes a convex surface close to the tiltable reflector 506 and may include a concave opposite surface coaxial with the convex surface. The convex surface supports a reflective polarizer 508, and the reflective polarizer 508 may have the same shape as the convex surface of the first lens element 514. A QWP 511 is arranged between the reflective polarizer 508 and the tiltable reflector 506. The QWP 511 may be supported by a window of the housing (not shown) of the tiltable reflector 506 and may even be supported by the tiltable reflector 506 itself, or may be laminated to the reflective polarizer 408.

[0056] The multi-channel coupler 540 may further include a second lens element 516 having a first coaxial optical surface 521 and a second 522 coaxial optical surface, and the first optical surface 521 faces the first lens element 514. A side surface 520 may be arranged between the first optical surface 521 and the second 522 optical surface for inputting a light beam 502 provided by the light source 504 into the second lens element 516. In the optical path of the light beam 502 input through the side surface 520 of the second lens element 516, an embedded steering mirror 518 may be arranged within the second lens element 516 for steering the light beam 502 towards the first optical surface 521 of the second lens element 516 and further through the first lens element 514.

[0057] The light beam 502 propagates through the side surface 520 and is reflected by the embedded steering mirror 518. Then, the light beam 402 sequentially propagates through the first surface 521 of the second lens element 516, through the first lens element 514, impinges on the tiltable reflector 506 and is reflected by it, is reflected by the reflective polarizer 508 to impinge on the tiltable reflector 506 again and is reflected by the tiltable reflector 506, propagates through the first lens element 514, propagates through the second lens element 516, and impinges on the exit pupil of the multi-channel scanner 530 located at the pupil. The first 514 and second 516 lens element surfaces may be optimized to provide the necessary collimation of the light beam 502 at the pupil replication waveguide 536. The above optical path is defined by the position and orientation of the reflective polarizer 508 and the QWP 511, and the reflective polarizer 508 and the QWP 511 are set in a configuration similar to the configuration described above with reference to Figure 2 a configuration similar to that described.

[0058] Reference Figures 6A to 6E, the near-eye display 600 includes a multi-channel scanner 630 coupled to a pupil replication waveguide 636. The multi-channel scanner 630 includes a light source 604, a tiltable reflector 606 (e.g., a packaged MEMS tiltable reflector having a window 607), and a multi-channel coupler 640. Similar to Figure 4A and Figure 4B the multi-channel coupler 440 of Figure 5A and Figure 5B the multi-channel coupler 540 of Figures 6A to 6E the multi-channel coupler 640 of Figure 2 employs a polarization-based double reflection configuration because it includes a reflective polarizer 608 for reflecting light having a first polarization state and transmitting light having a second polarization state orthogonal to the first polarization state, and a first QWP 611 disposed in the optical path between the reflective polarizer 608 and the tiltable reflector 606.

[0059] The multi-channel coupler 540 also includes a polarization beam splitter (PBS) 658 for reflecting light having a first polarization state and transmitting light having a second polarization state, and a first curved reflector 661 and a second curved reflector 662 adjacent to the adjacent surfaces of the PBS 658 for reflecting the light beam exiting the PBS 658 back to the PBS 658. The first curved reflector 661 and the reflective polarizer 608 can be arranged on opposite sides of the PBS 658, i.e., Figures 6A to 6E below and above the PBS 658 in

[0060] The multi-channel coupler 540 further includes a second QWP 612 disposed in the optical path between the PBS 658 and the first curved reflector 661 and configured to convert the polarization state of light between a first and a second polarization state during two-channel propagation through the second QWP 612, and a third QWP 613 disposed in the optical path between the PBS 658 and the second curved reflector 662 and configured to convert the polarization state of light between a first and a second polarization state during two-channel propagation through the third QWP 613. The multi-channel coupler 540 may further include a first lens element 671 in the optical path between the PBS 658 and the tiltable reflector 606, and a second lens element 672 in the optical path between the PBS 658 and the reflective polarizer 608. The light propagation through the multi-channel coupler 540 involves seven passes through the PBS 658 and will be considered in several steps described sequentially in the following Figure 6A , Figure 6B and Figure 6C .

[0061] Figure 6A The first three channels of the light beam 602 emitted by the light source 604 through the PBS 658 are shown in Figures 6B to 6E . Here, in Figures 6A to 6E , the first polarization state is a linearly polarized state oriented perpendicular to Figures 6A to 6E , while the second polarization state is a linearly polarized state oriented in the plane of Figure 6A . The light beam 602 emitted by the light source 604 ( Figure 6A ) is circularly polarized. The light beam 602 is focused to propagate through the opening 643 in the first curved reflector 661. Then, the light beam 602 propagates through the second QWP 612, strikes the PBS 658 when in the first polarization state, is reflected by the PBS 658 towards the tiltable reflector 606, propagates through the first QWP 611, is reflected by the tiltable reflector 606 for the first time, propagates through the first QWP 611 again, thereby converting to the second polarization state, propagates through the PBS 658 and the third QWP 613, strikes the second curved reflector 662, and propagates through the third QWP 613 again, thereby converting back to the first polarization state and being reflected by the PBS 658 towards the reflective polarizer 608 accordingly.

[0062] Figure 6BShown are the next two channels of the light beam 602 passing through the PBS 658. The light beam 602 reflected by the PBS 658 towards the reflective polarizer 608 in the first polarization state propagates back to the PBS 658 as shown, is reflected by the PBS 658 towards the second curved reflector 662, passes through the third QWP 613, is reflected by the second curved reflector 662 to pass through the third QWP 613 again, thereby switching to the second polarization state, passes through the PBS 658, passes through the first QWP 611, and is reflected by the tiltable reflector 606 towards the PBS 658 for the second time.

[0063] Figure 6C Shown are the last two channels of the light beam 602 passing through the PBS 658. The light beam 602 reflected by the tiltable reflector 606 for the second time passes through the first QWP 611 again, thereby switching to the first polarization state, is reflected by the PBS 658 to the first curved reflector 661, passes through the second QWP 612, is reflected by the first curved reflector 661, and passes through the second QWP 612 again, thereby switching to the second polarization state, passes through the PBS 658, and passes through the reflective polarizer 608 to the exit pupil located near the pupil replication waveguide 636.

[0064] Figure 6D Shown is the entire optical path of the light beam 602 in the near-eye display 600. Figure 6E Represents the entire optical path of the chief ray 699 of the light beam 602. In summary, the chief ray 699 passes through an optical path of one cube width seven times. Figure 6A Described are the first three channels through the cube, Figure 6B Described are the subsequent two channels, Figure 6C Described are the last two channels. In addition, the pupil of the tiltable reflector 606 is first relayed to the reflective polarizer 602, then relayed back to itself (doubling the reflection angle), and then relayed back to the reflective polarizer 608, this time transmitted to the pupil replication waveguide 636.

[0065] Figure 4A and Figure 4B the multi-channel coupler 440 of Figure 5A and Figure 5B the 540 of Figures 6A to 6EThe 640 performs similar functions: First, coupling the light beam emitted by the light source to the tiltable reflector; second, coupling the light beam reflected by the tiltable reflector back to the tiltable reflector; and third, coupling the light beam reflected multiple times from the tiltable reflector to the exit pupil or the pupil replica waveguide. Therefore, the above multi-channel coupler can be described as each having a first coupler portion that is responsible for coupling the light provided by the light source to the tiltable reflector; a second coupler portion for coupling the light reflected by the tiltable reflector back to the tiltable reflector; and a third coupling portion for coupling the light reflected multiple times from the tiltable reflector to the exit pupil. Different parts of the multi-channel coupler can share the same optical elements. This is shown in Figure 7 and Figure 8 shown below.

[0066] First referring to Figure 7 and further referring to Figure 4A , Figure 4B , Figure 5A and Figure 5B , the multi-channel coupler 740 ( Figure 7 ) represents Figure 4A and Figure 4B 's multi-channel coupler 440 and Figure 5A and Figure 5B 's multi-channel coupler 540. The first part 781 ( Figure 7 ) of the multi-channel coupler 740 couples the light provided by the light source 704 to the tiltable reflector 706 at the tilt angle α shown in Figure 7 . The first part 781 can include, for example, the opening 343 in the pupil replica waveguide 136 and the first 414 and second 416 lens elements ( Figure 4A and Figure 4B ); or the buried steering mirror 518 and the first 514 and second 516 lens elements ( Figure 5A and Figure 5B ). The second part 782 ( Figure 7 ) couples the light reflected by the tiltable reflector 706 at twice the tilt angle α back to the tiltable reflector 706. The light is coupled through a reflector that reflects the light from the tiltable reflector 706 back to the tiltable reflector 706. For example, the reflective polarizer 408 ( Figure 4A and Figure 4B ) reflects the light beam 402 back to the tiltable reflector 406; and Figure 5A and 5B 's reflective polarizer 508 ( Figure 5A and 5B ) reflects the light beam 502 back to the tiltable reflector 506. The third part 783 ( Figure 7)Couple the light reflected a second time at four times the tilt angle α to an exit pupil located near the pupil replication waveguide 736. The third portion 783 may also include a first lens element 414 and a second lens element 416( Figure 4A and Figure 4B );and a first lens element 514 and a second lens element 516( Figure 5A and Figure 5B ).

[0067] Now refer to Figure 8 and further refer to Figures 6A to 6E , the multi-channel coupler 840( Figure 8 ) represents Figures 6A to 6E 's multi-channel coupler 640. The first portion 881 of the multi-channel coupler 840( Figure 8 ) couples the light provided by the light source 804 to the tiltable reflector 806, and the tiltable reflector 806 shows the tilt angle α in Figure 8 . The first portion 881 may include, for example, an opening 643 in the first curved reflector 661, a PBS 658, and a first lens element 671( Figure 6A ). The second portion 882( Figure 8 ) couples the light 802* reflected by the tilt mirror at twice the tilt angle α back to the same position on the tilt mirror 706. In the multi-channel coupler 840, the light is coupled through a pupil auto-relay that relays the light 802* reflected by the tiltable reflector 806 for the first time back to the same position on the tiltable reflector 806. The pupil auto-relay is represented in Figure 6A and 6B 's multi-channel coupler 640 by the first lens element 671; PBS 658; the second curved reflector 662, and the second lens element 672, which returns the light beam 602 to the same position on the tiltable reflector 606. The third portion 883 of the multi-channel coupler 840( Figure 8 ) couples the light reflected a second time at four times the tilt angle α to the exit pupil. The third portion 883 may also include a first lens element 671, a PBS 658, a first curved reflector 661, and a second lens element 672( Figure 6C ). The third portion 883 is also a pupil relay, and thus it returns the light at four times the tilt angle α to the same position as at the zero tilt angle. Using (a) pupil relay and / or (a) pupil auto-relay is advantageous because it allows reducing the size of the tiltable mirrors 606, 806 and the grating inner couplers of the pupil replication waveguides 636, 836.

[0068] Refer to Figure 9A, the near-eye display 900 includes a first light source 903 for providing a first light beam 901 and a second light source 904 for providing a second light beam 902. The tiltable reflector 906 is configured to reflect the first light beam 901 and the second light beam 902 at variable angles. The pupil replication waveguide 936 is configured to receive the first light beam 901 and the second light beam 902 tilted by the tiltable reflector 906 and expand the first light beam 901 and the second light beam 902 onto the eye box 990 by providing multiple portions of the first light beam 901 and the second light beam 902 on the eye box 990, so that a user of the near-eye display 900 can comfortably view an image in the angular field provided by the near-eye display 900. The pupil replication waveguide 936 includes a polarization-selective input coupler 942 for input-coupling light in a first polarization state into the pupil replication waveguide 936 while transmitting light in a second polarization state orthogonal to the first polarization state.

[0069] The near-eye display 900 further includes a first curved reflector 961 configured to receive the first light beam 901 from the first light source 903 and reflect the first light beam 901 in a second polarization state to the tiltable reflector 906 and through the polarization-selective internal coupler 942. Since the first light beam 901 generated by the first light source 903 is in the second polarization state, the first light beam 901 does not substantially couple into the pupil replication waveguide 936 and propagates through the internal coupler 942.

[0070] Similarly, the second curved reflector can be configured to receive the second light beam 902 from the second light source 904 and reflect the second light beam 902 in a second polarization state to the tiltable reflector 906 and through the polarization-selective internal coupler 942 without substantially coupling into the pupil replication waveguide 936. The first 903 and second 904 light sources are arranged on opposite sides of the pupil replication waveguide of the first curved reflector 961 and the second 962 curved reflector. The first curved reflector 961 and the second curved reflector 962 can be constructed similar to Figures 6A to 6E the curved reflectors 661 and 662.

[0071] After reflection from the tiltable reflector, the first and second light beams are converted to a first polarization state. The conversion can be facilitated by (a plurality of) dedicated polarization conversion elements disposed in the optical path between the tiltable reflector 906 and the pupil replication waveguide 936. In some embodiments, the conversion can occur even without polarization conversion elements. For example, in embodiments where the first and second polarization states are left-handed circular polarization states, since upon reflection, the phase relationship between the X and Y components of the optical electric field remains unchanged while the propagation direction is reversed, a conversion from the second polarization state to the first polarization state occurs upon reflection from the tiltable reflector 906 or any reflector for TAT material, thereby changing the right-handed circular polarization to left-handed. Thus, the first light beam 901 and the second light beam 902 are intra-coupled into the pupil replication waveguide 936 through the intra-coupler 942.

[0072] The first light beam 901 and the second light beam 902, respectively generated by the first 903 and second 904 light sources, are scanned over different portions of the field of view (FOV) of the near-eye display 900, thereby expanding the overall FOV. The portions of the FOV can overlap, thereby providing a redundant region that can be used to provide increased spatial resolution, overall brightness, etc.

[0073] Reference Figure 10A and Figure 10B The near-eye display 1000 is similar to Figure 9A and Figure 9B the near-eye display 900 and includes similar elements such as the pupil replication waveguide 1036, the tiltable mirror 1006, etc. Figure 10A and Figure 10B The near-eye display 1000 of

[0074] Turning to Figure 11A and Figure 11B The near-eye display 1100 is similar to Figure 9A and Figure 9B the near-eye display 900 and includes similar elements, namely light sources 1103 and 1104, a pupil replication waveguide 1136 having a polarization-selective input coupler 1142, curved reflectors 1161 and 1162, and a tiltable reflector 1106 for reflecting at variable angles the light beams 1101 and 1102 respectively emitted by the light sources 1103 and 1104 and collimated by the curved reflectors 1161 and 1162. Figure 11A and Figure 11BThe near-eye display 1100 further includes folding mirrors 1191 and 1192 respectively disposed in the optical paths between the light sources 1103 and 1104 and the curved reflectors 1161 and 1162. The folding mirrors 1191 and 1102 enable the light sources 1103 and 1104 to be disposed on the same side of the pupil duplication waveguide as the curved reflectors 1161 and 1162, thereby reducing the number of channels through which the light beams 1101 and 1102 pass through the pupil duplication waveguide 1136. Each of the light sources 1103 and 1104 may include a set of individual emitters (source group 1 and source group 2 respectively); for this purpose, Figure 1 the light source 104, Figure 4A and Figure 4B the 404, Figure 5A and Figure 5B the 504, Figures 6A to 6E the 604, Figure 7 the 704, Figure 8 the 804, Figure 9A and Figure 9B the 903 and 904, and Figure 10A the 1003, 1004, 1053 and 1054 may each include a plurality of emitters. Several emitters may be provided for each color channel.

[0075] Reference Figure 12A , Figure 12B and Figure 12C , four red emitters 1200R may be provided for the red (R) color channel (dark shaded circle); four green emitters 1200G may be provided for the green (G) color channel (medium shaded circle); and four blue emitters 1200B may be provided for the blue (B) color channel (light shaded circle). Each of the emitters 1200R, 1200G and 1200B may be a ridge emitter sharing a common semiconductor substrate. By way of example only, the emitters 1200R, 1200G and 1200B may be arranged in a line pattern ( Figure 12A ), in a zigzag pattern ( Figure 12B ), or in a honeycomb pattern ( Figure 12C ).

[0076] Causing a plurality of emitters to illuminate the same tiltable reflector enables the scanning of the light beams generated by the emitters to be performed together as a group. When the light source includes a plurality of individual emitters, the illumination beam includes a plurality of sub-beams propagating together at a small angle to each other. In some embodiments, the maximum angular cone of the sub-beams may be less than 5 degrees, or less than 2 degrees or less than 1 degree. A plurality of emitters and, in some cases, a plurality of light sources may be used to provide redundancy, improve image resolution, increase overall image brightness, etc. in the event of failure of some of the light sources. Each of the plurality of light sources may be equipped with its own collimator.

[0077] Figure 1Near-eye display 100, Figure 4A and Figure 4B 400 of Figure 5A and Figure 5B 500 of Figures 6A to 6E 600 of Figure 9A and Figure 9B 900 of Figure 10A and Figure 10B 1000 of Figure 11A and Figure 11B 1100 of provide(s) (a) beam(s) to a low-angle coupling of a tiltable reflector. Herein, the term "low angle" refers to a low angle of incidence at the tiltable reflector when at a nominal (e.g., center or zero) angle of inclination, i.e., normal incidence. Figures 13A to 13C An advantage of having a low angle is shown in Figure 13A . First referring to

[0078] Figure 13B , the aspect ratio of the FOV of a projector using a tiltable reflector is plotted as a function of the angle of inclination, i.e., the angle of incidence at the tiltable reflector when in the nominal position or center position. The aspect ratio is plotted in four cases: FOV on the 75-degree by 50-degree axis; FOV on the 60-degree by 40-degree axis; FOV on the 45-degree by 30-degree axis; and FOV on the 30-degree by 20-degree axis. The aspect ratio decreases from 1.5 at zero angle of inclination (i.e., normal incidence) to approximately 1.1 at a 40-degree angle of inclination. Figure 13C shows a zero-angle scan angle region 1300B and an associated inset rectangular field of view 1302B. The zero-angle FOV 1302B solid angle covers most of the angular region 1300B. By comparison, Figure 1 and Figure 2 tiltable reflector 106 of Figure 4A and Figure 4B 406 of Figure 5A and Figure 5B 506 of Figures 6A to 6E 606 of Figure 7 706 of Figure 8 806 of Figure 9A and Figure 9B 906 of Figure 10A and Figure 10B 1006 of Figure 11A and Figure 11B1106 can be implemented as a MEMS tiltable reflector.

[0079] Embodiments of the present disclosure may be implemented in combination with or include an artificial reality system. Before being presented to a user, the artificial reality system adjusts sensory information about the external world obtained through senses such as visual information, audio, touch (haptic) information, acceleration, balance, etc. As a non-limiting example, artificial reality may include virtual reality (VR), augmented reality (AR), mixed reality (MR), hybrid reality, or some combination and / or derivative thereof. Artificial reality content may include fully generated content or generated content combined with captured (e.g., real-world) content. Artificial reality content may include video, audio, body or haptic feedback, or some combination thereof. Any of these contents may be presented in a single channel or multiple channels, such as in a stereoscopic video that produces a three-dimensional effect for viewers. Additionally, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof for creating content in the artificial reality and / or otherwise using in the artificial reality (e.g., performing activities in the artificial reality). An artificial reality system that provides artificial reality content may be implemented on various platforms, including wearable displays such as HMDs connected to a host computer system, standalone HMDs, near-eye displays having a glasses form factor, mobile devices or computing systems, or any other hardware platform capable of providing artificial reality content to one or more viewers.

[0080] Reference Figure 14A , to be more immersed in the AR / VR environment, the HMD 1400 is an example of an AR / VR wearable display system that surrounds the user's face. For example, the HMD 1400 is Figure 1 100 of Figure 4A and Figure 4B 400 of Figure 5A and Figure 5B 500 of Figures 6A to 6E 600 of Figure 9A and Figure 9B 900 of Figure 10A and Figure 10B 1000 of Figure 11A and Figure 11BExample of 1100. The function of the HMD 1400 is to enhance the view of the physical, real-world environment with computer-generated images and / or generate a fully virtual 3D image. The HMD 1400 may include a front body 1402 and a strap 1404. The front body 1402 is configured to be placed in front of the user's eyes in a reliable and comfortable manner, and the strap 1404 can be stretched to fix the front body 1402 on the user's head. A display system 1480 may be provided in the front body 1402 for presenting AR / VR images to the user. The side 1406 of the front body 1402 may be opaque or transparent.

[0081] In some embodiments, the front body 1402 includes a locator 1408 and an inertial measurement unit (IMU) 1410 for tracking the acceleration of the HMD 1400, and a position sensor 1412 for tracking the position of the HMD 1400. The IMU 1410 is an electronic device that generates data indicating the position of the HMD 1400 based on measurement signals received from one or more position sensors 1412, and the position sensors 1412 generate one or more measurement signals in response to the movement of the HMD 1400. Examples of the position sensors 1412 include: one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor for detecting movement, a sensor type for error correction of the IMU 1410, or some combination thereof. The position sensors 1412 may be located outside the IMU 1410, inside the IMU 1410, or some combination thereof.

[0082] The locator 1408 is tracked by an external imaging device of the virtual reality system, so that the virtual reality system can track the position and orientation of the entire HMD 1400. The information generated by the IMU 1410 and the position sensors 1412 can be compared with the position and orientation obtained by tracking the locator 1408 to improve the tracking accuracy of the position and orientation of the HMD 1400. Accurate position and orientation are very important for presenting a suitable virtual scene to the user when the user moves and rotates in 3D space.

[0083] The HMD 1400 may also include a depth camera accessory (DCA) 1411 that captures data describing the depth information of a local area around part or all of the HMD 1400. For this purpose, the DCA 1411 may include a lidar (LIDAR) or a similar device. The depth information can be compared with the information from the IMU 1410 to more accurately determine the position and orientation of the HMD 1400 in 3D space.

[0084] The HMD 1400 may also include an eye tracking system 1414 for determining the orientation and position of the user's eyes in real time. The obtained position and orientation of the eyes also allow the HMD 1400 to determine the user's gaze direction and accordingly adjust the images generated by the display system 1480. In one embodiment, the convergence degree, i.e., the convergence angle of the user's eye gaze, is determined. The determined gaze direction and convergence angle can also be used to compensate for visual artifacts in real time based on the viewing angle and eye position. In addition, the determined convergence degree and gaze angle can be used for interacting with the user, highlighting objects, bringing objects to the foreground, creating additional objects or pointers, etc. An audio system may also be provided, including, for example, a set of small speakers built into the front body 1402.

[0085] Reference Figure 14B , the AR / VR system 1450 includes Figure 14A the HMD 1400, an external console 1490 that stores various AR / VR applications, settings, and calibration procedures, 3D videos, etc., and an input / output (I / O) interface 1415 for operating the console 1490 and / or interacting with the AR / VR environment. The HMD 1400 can be "tethered" to the console 1490 via a physical cable or connected to the console 1490 via a wireless communication link such as Wi-Fi. There can be multiple HMDs 1400, each HMD 1400 having an associated I / O interface 1415, and each HMD 1400 and the (multiple) I / O interfaces 1415 communicate with the console 1490. In an alternative configuration, different and / or additional components may be included in the AR / VR system 1450. Additionally, in some embodiments, the functions described in connection with Figure 14A and Figure 14B one or more of the components shown may be different from the way the functions are distributed among the components described in connection with Figure 14A and Figure 14B . For example, some or all of the functions of the console 1415 may be provided by the HMD 1400, and vice versa. The HMD 1400 may be equipped with a processing module capable of implementing such functions.

[0086] As described above with reference to Figure 14A , the HMD 1400 may include an eye tracking system 1414 for tracking eye position and orientation, determining the gaze angle and convergence angle, etc. ( Figure 14B ), an IMU 1410 for determining the position and orientation of the HMD 1400 in 3D space, a DCA 1411 for capturing the external environment, a position sensor 1412 for independently determining the position of the HMD 1400, and a display system 1480 for displaying AR / VR content to the user. The display system 1480 includes ( Figure 14B)An electronic display 1425, such as but not limited to, a liquid crystal display (LCD), an organic light emitting display (OLED), an inorganic light emitting display (ILED), an active matrix organic light emitting diode (AMOLED) display, a transparent organic light emitting diode (TOLED) display, a projector, or a combination thereof. The display system 1480 also includes an optical block 1430, which functions to transmit the image generated by the electronic display 1425 to the user's eyes. The optical block may include various lenses, such as refractive lenses, Fresnel lenses, diffractive lenses, active or passive Pancharatnam-Berry phase (PBP) lenses, liquid crystal lenses, etc., pupil replication waveguides, grating structures, coatings, etc. The display system 1480 may also include a zoom module 1435, which may be a part of the optical block 1430. The function of the zoom module 1435 is to adjust the focus of the optical block 1430, such as compensating for the convergence-accommodation conflict, correcting the visual defects of a specific user, offsetting the aberrations of the optical block 1430, etc.

[0087] The I / O interface 1415 is a device that allows the user to send action requests and receive responses from the console 1490. An action request is a request to perform a specific action. For example, the action request may be an instruction to start or end capturing image or video data, or an instruction to perform a specific action within an application. The I / O interface 1415 may include one or more input devices, such as a keyboard, a mouse, a game controller, or any other suitable device for receiving action requests and transmitting the action requests to the console 1490. The action requests received by the I / O interface 1415 are transmitted to the console 1490, and the console 1490 performs the action corresponding to the action request. In some embodiments, the I / O interface 1415 includes an IMU, which captures calibration data indicating an estimated position of the I / O interface 1415 relative to the initial position of the I / O interface 1415. In some embodiments, the I / O interface 1415 may provide haptic feedback to the user according to instructions received from the console 1490. For example, haptic feedback may be provided when an action request is received, or the console 1490 transmits an instruction to the I / O interface 1415 such that the I / O interface 1415 generates haptic feedback when the console 1490 performs an action.

[0088] The console 1490 may provide content to the HMD 1400 for processing according to information received from one or more of the IMU 1410, the DCA 1411, the eye tracking system 1414, and the I / O interface 1415. In Figure 14B the example shown, the console 1490 includes an application storage device 1455, a tracking module 1460, and a processing module 1465. Some embodiments of the console 1490 may have the same as those combined Figure 14BThe described modules or components are different from other modules or components. Similarly, the functions further described below may be different from the way they are distributed among the components of the console 1490 as described in conjunction with Figure 14A and Figure 14B described.

[0089] The application storage device 1455 may store one or more applications for execution by the console 1490. An application is a set of instructions that, when executed by a processor, generate content to be presented to a user. The content generated by an application may be responsive to input received from the user via the mobile HMD 1400 or the I / O interface 1415. Examples of applications include: game applications, presentation and conferencing applications, video playback applications, or other suitable applications.

[0090] The tracking module 1460 may use one or more calibration parameters to calibrate the AR / VR system 1450 and may adjust one or more calibration parameters to reduce errors in determining the position of the HMD 1400 or the I / O interface 1415. The calibration performed by the tracking module 1460 also takes into account information received from the IMU 1410 in the HMD 1400 and / or the IMU (if any) included in the I / O interface 1415. Additionally, if tracking of the HMD 1400 is lost, the tracking module 1460 may recalibrate some or all of the AR / VR system 1450.

[0091] The tracking module 1460 may track the movement of the HMD 1400 or the I / O interface 1415, the IMU 1410, or some combination thereof. For example, the tracking module 1460 may determine the position of the reference point of the HMD 1400 in the mapping of the local area based on information from the HMD 1400. The tracking module 1460 may also determine the position of the reference point of the HMD 1400 or the reference point of the I / O interface 1415 using data from the IMU 1410 indicating the position of the HMD 1400 or using data from the IMU included in the I / O interface 1415 indicating the position of the I / O interface 1415, respectively. Additionally, in some embodiments, the tracking module 1460 may use data indicating the position or a portion of the HMD 1400 from the IMU 1410 and a representation of the local area from the DCA 1411 to predict the future position of the HMD 1400. The tracking module 1460 provides the estimated or predicted future position of the HMD 1400 or the I / O interface 1415 to the processing module 1465.

[0092] The processing module 1465 can generate a 3D map of some or all of the surrounding area (“local area”) in the HMD 1400 based on the information received from the HMD 1400. In some embodiments, the processing module 1465 determines the depth information for the 3D map of the local area based on the information received from the DCA 1411 related to the techniques used in computing depth. In various embodiments, the processing module 1465 can use the depth information to update the model of the local area and generate content partially based on the updated model.

[0093] The processing module 1465 executes applications within the AR / VR system 1450 and receives position information, acceleration information, velocity information, predicted future position, or some combination thereof of the HMD 1400 from the tracking module 1460. Based on the received information, the processing module 1465 determines the content to be provided to the HMD 1400 for presentation to the user. For example, if the received information indicates that the user has looked left, the processing module 1465 generates content for the HMD 1400 that reflects the user's movement in a virtual environment or in an environment where the local area is enhanced with additional content. Additionally, the processing module 1465 executes an action within an application running on the console 1490 in response to an action request received from the I / O interface 1415 and provides feedback to the user that the action has been executed. The feedback provided can be visual or auditory feedback through the HMD 1400, or tactile feedback through the I / O interface 1415.

[0094] In some embodiments, based on the eye tracking information received from the eye tracking system 1414 (e.g., the orientation of the user's eyes), the processing module 1465 determines the resolution of the content provided to the HMD 1400 for presentation to the user on the electronic display 1425. The processing module 1465 can provide the content to the HMD 1400 with the maximum pixel resolution in the foveal region where the user is fixating on the electronic display 1425. The processing module 1465 can provide a lower pixel resolution in other areas of the electronic display 1425, thereby reducing the power consumption of the AR / VR system 1450 and saving computing resources of the console 1490 without compromising the user's visual experience. In some embodiments, the processing module 1465 can also use the eye tracking information to adjust the display position of an object on the electronic display 1425 to prevent convergence-accommodation conflicts and / or counteract optical distortion and aberration.

[0095] The hardware for implementing the various illustrative logics, logic blocks, modules, and circuits described in connection with the aspects disclosed herein can be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with DSP cores, or any other such configuration. Alternatively, certain steps or methods may be performed by circuitry specific to a given function.

[0096] The scope of the present disclosure is not limited to the specific embodiments described herein. Indeed, various other embodiments and modifications will be apparent to those of ordinary skill in the art from the foregoing description and drawings in addition to those described herein. Accordingly, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Moreover, although the present disclosure is described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto, and that the present disclosure may be advantageously implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the present disclosure described herein.

Claims

1. A near-eye display for providing an angular field image at an eye box, the near-eye display including a multi-channel scanner for scanning a light beam, the multi-channel scanner including: a light source for providing the light beam; a tiltable reflector for reflecting the light beam provided by the light source by tilting the tiltable reflector at a variable angle; a multi-channel coupler for receiving the light beam from the light source, coupling the light beam to the tiltable reflector, receiving the light beam reflected from the tiltable reflector for the first time at twice the variable angle, redirecting the light beam back to the tiltable reflector, and receiving the light beam reflected from the tiltable reflector for the second time and coupling the light beam to an exit pupil of the multi-channel scanner; a reflective polarizer for reflecting light having a first polarization state and transmitting light having a second polarization state orthogonal to the first polarization state; and a first QWP disposed in an optical path between the reflective polarizer and the tiltable reflector and configured to convert the polarization state of light between the first polarization state and the second polarization state after two-channel propagation through the first QWP, wherein in operation, the light beam having the second polarization state sequentially propagates through the reflective polarizer and the first QWP, impinges on the tiltable reflector for the first time, is reflected by the tiltable reflector to propagate through the first QWP again, thereby converting to the first polarization state, is reflected by the reflective polarizer, propagates through the first QWP and impinges on the tiltable reflector for the second time, is reflected by the tiltable reflector to propagate through the first QWP, thereby converting back to the second polarization state, and propagates through the reflective polarizer to the exit pupil.

2. The near-eye display according to claim 1, wherein the multi-channel coupler includes a first lens element having positive optical power and includes a convex surface adjacent to the tiltable reflector, the convex surface supporting the reflective polarizer.

3. The near-eye display according to claim 2, wherein the multi-channel coupler further includes a second lens element disposed between the first lens element and the exit pupil, wherein in operation, the light beam provided by the light source sequentially propagates through the second lens element, through the first lens element, impinges on the tiltable reflector, is reflected by the reflective polarizer to impinge on the tiltable reflector for the second time and is reflected by the tiltable reflector, propagates through the first lens element, propagates through the second lens element, and impinges on the exit pupil of the multi-channel coupler.

4. The near-eye display according to claim 2, wherein the multi-channel coupler further includes a second lens element disposed between the first lens element and the exit pupil, the second lens element including: a first coaxial optical surface and a second coaxial optical surface, the first coaxial optical surface facing the first lens element; On a side between the first coaxial optical surface and the second coaxial optical surface, the side being for inputting the light beam provided by the light source into the second lens element; and a buried turning mirror, the buried turning mirror being within the second lens element in an optical path of the light beam input through the side of the second lens element, for turning the light beam to the first coaxial optical surface of the second lens element.

5. The near-eye display according to claim 1, further comprising: a polarization beam splitter PBS for reflecting light having the first polarization state and transmitting light having the second polarization state; a first curved reflector and a second curved reflector, the first curved reflector and the second curved reflector being adjacent to surfaces of the PBS, for reflecting the light beam exiting the PBS back to the PBS, wherein the first curved reflector and the reflective polarizer are arranged on opposite sides of the PBS, and wherein the second curved reflector and the tiltable reflector are arranged on opposite sides of the PBS; a second QWP, arranged in an optical path between the PBS and the first curved reflector, and configured to convert a polarization state of light between the first polarization state and the second polarization state after double-channel propagation through the second QWP; and a third QWP, arranged in an optical path between the PBS and the second curved reflector, and configured to convert a polarization state of light between the first polarization state and the second polarization state after double-channel propagation through the second QWP.

6. The near-eye display according to claim 5, wherein in operation, the light beam provided by the light source propagates in sequence as follows: through an opening in the first curved reflector, through the second QWP, while in the first polarization state, impinges on the PBS, is reflected by the PBS towards the tiltable reflector, propagates through the first QWP, is first reflected by the tiltable reflector, propagates through the first QWP again, thereby converting to the second polarization state, propagates through the PBS and the third QWP, impinges on the second curved reflector, propagates through the third QWP again, thereby converting to the first polarization state, and is reflected by the PBS towards the reflective polarizer.

7. The near-eye display according to claim 6, wherein in operation, the light beam in the first polarization state reflected by the PBS towards the reflective polarizer propagates back to the PBS, is reflected by the PBS towards the second curved reflector, propagates through the third QWP, is reflected by the second curved reflector to propagate through the third QWP again, thereby converting to the second polarization state, propagates through the PBS, through the first QWP, and is secondarily reflected by the tiltable reflector towards the PBS.

8. The near-eye display according to claim 7, wherein in operation, the light beam reflected a second time by the tiltable reflector propagates through the first QWP again, thereby being converted to the first polarization state, reflected by the PBS towards the first curved reflector, propagates through the second QWP, reflected by the first curved reflector, propagates through the second QWP again, thereby being converted to the second polarization state, propagates through the PBS, and propagates through the reflective polarizer to the exit pupil.

9. The near-eye display according to claim 5, further comprising a first lens element in the optical path between the PBS and the tiltable reflector, and a second lens element in the optical path between the PBS and the reflective polarizer.

10. The near-eye display according to claim 1, wherein the multi-channel coupler comprises a first coupler portion for coupling the light provided by the light source to the tiltable reflector.

11. The near-eye display according to claim 10, wherein the multi-channel coupler comprises a reflector for reflecting the light from the tiltable reflector back to the tiltable reflector.

12. The near-eye display according to claim 10, wherein the multi-channel coupler comprises a second coupler portion, and the second coupler portion comprises a pupil auto-relay for relaying the light reflected by the tiltable reflector back to the tiltable reflector for the first time.

13. The near-eye display according to claim 12, further comprising a third coupler portion for relaying the light reflected a second time by the tiltable reflector to the exit pupil of the multi-channel scanner.

14. The near-eye display according to any one of the preceding claims, further comprising: a pupil replication waveguide for receiving the light beam tilted by the tiltable reflector and expanding the light beam over the eye box by providing multiple portions of the light beam over the eye box.

15. The near-eye display according to claim 14, wherein the light source and the multi-channel coupler are arranged on opposite sides of the pupil replication waveguide, and the pupil replication waveguide comprises an opening therein for propagating the light beam provided by the light source for coupling to the multi-channel coupler.

16. The near-eye display according to claim 14, wherein the tiltable reflector comprises a tiltable microelectromechanical system (MEMS) reflector.

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