Patent Description:
The present disclosure relates to wearable headsets, and in particular to components and modules for wearable visual display headsets.

Head mounted displays (HMDs), helmet mounted displays, near-eye displays (NEDs), and the like are being increasingly used for displaying virtual reality (VR) content, augmented reality (AR) content, mixed reality (MR) content, etc. Such displays are finding applications in diverse fields including entertainment, education, training and biomedical science, to name just a few examples. The displayed VR / AR / MR content can be three-dimensional (3D) to enhance the experience and to match virtual objects to real objects observed by the user. Eye position and gaze direction, and/or orientation of the user may be tracked in real time, and the displayed imagery may be dynamically adjusted depending on the user's head orientation and gaze direction, to provide a better experience of immersion into a simulated or augmented environment.

Compact display devices are desired for head-mounted displays. Because a display of HMD or NED is usually worn on the head of a user, a large, bulky, unbalanced, and/or heavy display device would be cumbersome and may be uncomfortable for the user to wear.

Projector-based displays, e.g. scanning projector displays, provide images in angular domain, which can be observed by a user's eye directly, without an intermediate screen or a display panel. A pupil-replicating waveguide is used to carry the image in angular domain to the user's eye. The lack of a screen or a display panel in a scanning projector display enables size and weight reduction of the display. The image may be obtained by scanning a light beam over the field of view (FOV) of the display.

<CIT> describes, for achieving an expanded observation range without sacrificing resolution, a scanning optical system that includes a scanner that deflects laser light from a light source while changing a deflection angle of the laser light; a polarization beam splitter that is capable of splitting-off the laser light from an optical path of the laser light deflected by the scanner; a polarization beam splitter that is disposed between the light source and the scanner and that causes the laser light split-off by the polarization beam splitter to travel toward the scanner; and a first relay optical system that has 1x relay magnifying power and that is disposed between the polarization beam splitter and the polarization beam splitter. The first relay optical system relays the laser light split-off by the polarization beam splitter so as to cause the laser light to be incident again on the scanner at the same position as an incident position of the laser light from the light source via the polarization beam splitter.

<CIT> describes a near-eye optical display system that has a laser source to direct modulated light toward a scan mirror and objective lens that define a focal surface. Pupil relay optics relay a first pupil at the scan mirror to a second pupil at an eye lens, the pupil relay optics defining an optical axis extending between pupils and having a curved mirror that transmits substantially half of the modulated beam and that has a first center of curvature at the first pupil and a first polarizer in the path of light from the scan mirror to reflect incident light of a first polarization and first angle toward the curved mirror surface and transmit incident light of an orthogonal polarization and second angle, wherein the pupil relay optics direct the modulated light beam twice to the first polarizer, and wherein the modulated light incident the second time is collimated and directed toward the second pupil.

<CIT> describes a near-eye optical display system that utilizes a compact display engine that couples image light from an imager to a waveguide-based display having diffractive optical elements (DOEs) that provide exit pupil expansion in two directions. The display engine comprises a pair of single axis MEMS (Micro Electro Mechanical System) scanners that are configured to reflect the image light through horizontal and vertical scan axes of the display system's field of view (FOV) using raster scanning. The MEMS scanners are arranged with their axes of rotation at substantially right angles to each other and operate with respective quarter wave retarder plates and a polarizing beam splitter (PBS) to couple the image light into an in-coupling DOE in the waveguide display without the need for additional optical elements such as lenses or relay systems.

<CIT> describes a head up display that can use a catadioptric collimating system. The head up display includes an image source. The head up display also includes a collimating mirror, and a polarizing beam splitter. The light from the image source enters the beam splitter and is reflected toward the collimating mirror. The light striking the collimating mirror is reflected through the beam splitter toward a combiner. A field lens can include a diffractive surface. A corrector lens can be disposed after the beam splitter.

A scanning projector display requires an optical scanner, which is typically based on a tiltable reflector. The scanner should be capable of scanning a light beam over the entire field of view (FOV) of the display. As the light beam is scanned, its brightness and/or color may vary in coordination with the scanning, to provide an image in angular domain. The light beam may be scanned in two directions, e.g. over X- and Y-viewing angles. When the frame rate is high enough, the eye integrates the scanned light beam, enabling the user to see the displayed imagery substantially without flicker.

One challenge of constructing a scanning display with a tiltable reflector is the required angular scanning range of the tiltable reflector. A large scanning range requires compromises is other parameters, including flexure stiffness and scan rate (frequency). Thin, flexible hinges cannot support a larger reflector required to provide a desired beam size and image quality. In accordance with this disclosure, a light beam may be made to impinge multiple times onto a same tiltable reflector, thereby multiplying the scanning range without having to increase the maximum tilting angle of the reflector.

According to an aspect of the invention, there is provided a near-eye display according to claim <NUM>.

The multipass coupler may include a first lens element having positive optical power and comprising a convex surface proximate the tiltable reflector, the convex surface supporting the reflective polarizer. Optionally the multipass coupler may also 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 in sequence though the second lens element, through the first lens element, impinges onto the tiltable reflector, is reflected by the reflective polarizer to impinge onto and get reflected by the tiltable reflector for the second time, propagates through the first lens element, propagates through the second lens element, and impinges onto the exit pupil of the multipass scanner. In some embodiments, the second lens element may include first and second coaxial optical surfaces, the first optical surface facing the first lens element, a side face between the first and second optical surfaces for inputting the light beam provided by the light source into the second lens element and a buried turn mirror within the second lens element in an optical path of the light beam inputted through the side face of the second lens element, for turning the light beam towards the first optical surface of the second lens element.

In some embodiments, the multipass scanner may include a polarization beamsplitter (PBS) for reflecting light having the first polarization state and transmitting light having the second polarization state. First and second curved reflectors may be disposed proximate adjoining surfaces of the PBS for reflecting the light beam exiting the PBS back towards 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 an optical path between the PBS and the first curved reflector and configured to convert a polarization state of light between the first and second polarization states upon a double-pass propagation through the second QWP. A third QWP may be disposed in an optical path between the PBS and the second curved reflector and configured to convert a polarization state of light between the first and second polarization states upon a double-pass propagation through the second QWP. In operation, the light beam provided by the light source may propagate in sequence: through an opening in the first curved reflector, through the second QWP, impinges, while in the first polarization state, onto the PBS, is reflected by the PBS towards the tiltable reflector, propagates through the first QWP, is reflected by the tiltable reflector for the first time, propagates again through the first QWP thereby converting to the second polarization state, propagates through the PBS and the third QWP, impinges onto 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. The light beam reflected by the PBS towards the reflective polarizer in the first polarization state may optionally propagate back towards 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 for the second time towards the PBS. The light beam reflected by the tiltable reflector for the second time may optionally propagate again through the first QWP thereby converting to the first polarization state, be reflected by the PBS to 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 PBS, and propagate through the reflective polarizer to the exit pupil.

In some embodiments, the multipass scanner may further include a first lens element in an optical path between the PBS and the tiltable reflector, and a second lens element in an optical path between the PBS and the reflective polarizer. In embodiments where the multipass coupler comprises a first coupler portion for coupling light provided by the light source to the tiltable reflector, the multipass coupler may include a reflector for reflecting light from the tiltable reflector back towards the tiltable reflector. The multipass coupler may further include a second coupler portion comprising a pupil auto-relay for relaying light reflected by the tiltable reflector for the first time back to the tiltable reflector, and the multipass coupler may optionally comprise a third coupler portion for relaying light reflected by the tiltable reflector for the second time to the exit pupil of the multipass scanner.

The near-eye display may include a pupil- replicating waveguide for receiving the light beam tilted by the tiltable reflector and expanding the light beam over the eyebox by providing multiple portions of the light beam over the eyebox.

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

In accordance with the present disclosure not according to the claimed invention, there is further provided a near eye display for providing an image in angular domain at an eyebox. 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 and second light beams at a variable angle; a pupil-replicating waveguide for receiving the first and second light beams tilted by the tiltable reflector and expanding the first and second light beams over the eyebox by providing multiple portions of the first and second light beams over the eyebox. The pupil-replicating waveguide includes a polarization-selective in-coupler for in- coupling light in a first polarization state while transmitting through light in a second polarization state orthogonal to the first polarization state. The near-eye display further includes a pupil-replicating waveguide for receiving the light beam tilted by the tiltable reflector and expanding the light beam over the eyebox by providing multiple portions of the light beam over the eyebox; and a multipass 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 a 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 a second time and coupling the light beam to the pupil-replicating waveguide. The first and second light sources may be disposed on an opposite side of the pupil-replicating waveguide from the first and second curved reflectors.

In embodiments where the first and second light sources are disposed on a same side of the pupil-replicating waveguide as the first and second curved reflectors, the near-eye display may further include a first folding mirror in an optical path between the first light source and the first curved reflector; and a second folding mirror in an optical path between the second light source and the second curved reflector.

Exemplary embodiments will now be described in conjunction with the drawings, in which:.

While the present teachings are described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives and equivalents, as will be appreciated by those of skill in the art. All statements herein reciting principles, aspects, and embodiments of this disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof.

As used herein, the terms "first", "second", and so forth are not intended to imply sequential ordering, but rather are intended to distinguish one element from another, unless explicitly stated. Similarly, sequential ordering of method steps does not imply a sequential order of their execution, unless explicitly stated. In <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, similar reference numerals denote similar elements.

Referring to <FIG>, a near-eye display <NUM> includes a multipass scanner <NUM> optically coupled to a pupil-replicating waveguide <NUM>. The multipass scanner <NUM> may be used to provide an image in angular domain to the pupil-replicating waveguide <NUM> by scanning a light beam <NUM> of a variable brightness and/or color over a display's FOV. The light beam <NUM> is emitted by a light source <NUM>.

The multipass scanner <NUM> includes a tiltable reflector <NUM> for reflecting the light beam <NUM> provided by the light source <NUM>. The light beam <NUM> is scanned, or steered, by tilting the tiltable reflector <NUM> at a variable angle. The tiltable reflector <NUM> may include a microelectromechanical (MEMS) reflector tiltable at a controllable angle by applying a control signal to its electrodes. The MEMS reflector may include a mirror and/or a grating, for example. The multipass scanner <NUM> further includes a multipass coupler <NUM> configured for receiving the light beam <NUM> from the light source <NUM> and coupling the light beam <NUM> to the tiltable reflector <NUM>. The multipass coupler <NUM> directs the light beam <NUM> to the tiltable reflector <NUM> and receives the light beam <NUM> reflected from the tiltable reflector <NUM> for a first time (event <NUM>) at twice the angle of tilt of the tiltable reflector <NUM>, and redirects the light beam <NUM> back to the tiltable reflector <NUM> for a secondary reflection. A portion <NUM> of the multipass coupler <NUM> that couples the light beam <NUM> back to the tiltable reflector <NUM> may include e.g. a mirror or a pupil auto-relay. Examples of both will be considered further below.

The multipass coupler <NUM> redirects the light beam <NUM> back to the tiltable reflector <NUM> and receives the light beam <NUM> reflected from the tiltable reflector for a second time (event <NUM>) at an increased angle of four times the variable angle, and couples the light beam to an exit pupil <NUM> of the multipass scanner <NUM>. The increased angle of the light beam <NUM> is due to multiple reflections from the tiltable reflector <NUM>. The pupil-replicating waveguide <NUM> may be disposed proximate the exit pupil <NUM> for receiving the light beam at four times the variable angle of tilt of the tiltable reflector <NUM>. In some embodiments, the multipass coupler <NUM> has an optical magnification factor between the light source <NUM> and the exit pupil <NUM> of greater or smaller than unity, in which case the angle of the light beam <NUM> at the exit pupil <NUM> may be different from four times the tilt angle of the tiltable reflector <NUM>, but is typically larger than the tilt angle of the tiltable reflector <NUM>.

In some embodiments, the multipass coupler <NUM> may be based on a polarization diversity configuration ensuring a double reflection of the light beam <NUM> from the tiltable mirror <NUM>. Referring to <FIG>, a multipass coupler <NUM> includes a reflective polarizer <NUM> for reflecting light having a first polarization state and transmitting light having a second polarization state orthogonal to the first polarization state. The first and second polarization states may be orthogonal linear polarization states or circular polarization states of opposite handedness, for example.

A quarter-wave waveplate (QWP) <NUM> is disposed in an optical path between the reflective polarizer <NUM> and the tiltable reflector <NUM> and configured to convert a polarization state of light between the first and second polarization states upon a double-pass propagation through the QWP <NUM>. In operation, the light beam <NUM> having the second polarization state PS2 propagates in sequence through the pupil-replicating waveguide <NUM>, through the reflective polarizer <NUM> and the QWP <NUM>, impinges onto the tiltable reflector <NUM> and is reflected by the tiltable reflector for the first time (event <NUM>) to propagate again through the QWP <NUM> thereby converting to the first polarization state PS1, is reflected by the reflective polarizer <NUM>, propagates through the QWP <NUM> and impinges onto the tiltable reflector for the second time, is reflected by the tiltable reflector for the second time (event <NUM>) to propagate through the QWP <NUM> thereby converting back to the second polarization state PS2, and consequently propagates through the reflective polarizer <NUM> towards the pupil-replicating waveguide <NUM>, where it is in-coupled to propagate in the pupil-replicating waveguide <NUM>.

It is to be understood that the light beams <NUM> are shown in <FIG> vertically separated for illustration only. In an actual device, the light beams <NUM> may propagate along a same path at normal angle of incidence onto the tiltable reflector <NUM>, and deviate from a same path at non-zero angles of incidence onto the tiltable reflector <NUM> in accordance with laws of reflection. An in-coupler, e.g. a grating in-coupler <NUM> shown in <FIG>, may be used to in-couple the light beam <NUM> into the pupil-replicating waveguide <NUM>. To make sure that the light beam <NUM> is not in-coupled into the pupil-replicating waveguide <NUM> at first incidence, the grating in-coupler <NUM> may include an opening <NUM>. The light beam <NUM> may be focused onto the opening <NUM> to propagate through the grating in-coupler <NUM> substantially without loss.

Implementations of the polarization-based multipass coupler <NUM> of <FIG> will now be considered. Referring to <FIG>, a near-eye display <NUM> includes a multipass scanner <NUM> coupled to the pupil-replicating waveguide <NUM>. The multipass scanner <NUM> includes a light source <NUM>, a tiltable reflector <NUM>, and a multipass coupler <NUM>. The light source <NUM> is disposed on an opposite side of the pupil-replicating waveguide <NUM> than the tiltable reflector <NUM> and the multipass coupler <NUM>. The multipass coupler <NUM> includes a first lens element <NUM> having positive optical power (i.e. focusing power). The first lens element <NUM> includes a convex surface proximate the tiltable reflector <NUM>, and may include a concave opposite surface coaxial with the convex surface. The convex surface supports a reflective polarizer <NUM>, which may be of a same shape as the convex surface of the first lens element <NUM>. A QWP <NUM> is disposed between the reflective polarizer <NUM> and the tiltable reflector <NUM>. The QWP <NUM> may be supported by a window of an enclosure, not shown, of the tiltable reflector <NUM>, and may even be supported by the tiltable reflector <NUM> itself, or may be laminated to the reflective polarizer <NUM>.

The multipass coupler <NUM> may further include a second lens element <NUM> disposed between the first lens element <NUM> and the exit pupil located proximate the pupil-replicating waveguide <NUM>. In operation, the light source <NUM> provides a light beam <NUM> which converges onto the opening <NUM> in the input coupler <NUM> of the pupil-replicating waveguide <NUM> (<FIG>). The light beam <NUM> (<FIG>) propagates through the opening <NUM> and is coupled to the multi-pass coupler <NUM>. Then, the light beam <NUM> propagates in sequence though the second lens element <NUM>, through the first lens element <NUM>, impinges onto and gets reflected by the tiltable reflector <NUM>, is reflected by the reflective polarizer <NUM> to impinge onto and get reflected by the tiltable reflector <NUM> for the second time, propagates through the first lens element <NUM>, propagates through the second lens element <NUM>, and impinges onto the exit pupil of the multipass scanner <NUM> located at the pupil-replicating waveguide <NUM>. The first <NUM> and second <NUM> lens elements surfaces may be optimized to provide the necessary collimation of the light beam <NUM> at the pupil-replicating waveguide <NUM>. The above described optical path is defined by the position and orientation of the reflective polarizer <NUM> and the QWP <NUM>, which are configured as described above with reference to <FIG>.

Turning now to <FIG>, a near-eye display <NUM> includes a multipass scanner <NUM> coupled to a pupil-replicating waveguide <NUM>. The multipass scanner <NUM> includes a light source <NUM>, a tiltable reflector <NUM>, and a multipass coupler <NUM>. The light source <NUM> is disposed on a same side of the pupil-replicating waveguide <NUM> as the tiltable reflector <NUM> and the multipass coupler <NUM>. The multipass coupler <NUM> includes a first lens element <NUM> having positive optical power. The first lens element <NUM> includes a convex surface proximate the tiltable reflector <NUM>, and may include a concave opposite surface coaxial with the convex surface. The convex surface supports a reflective polarizer <NUM>, which may be of a same shape as the convex surface of the first lens element <NUM>. A QWP <NUM> is disposed between the reflective polarizer <NUM> and the tiltable reflector <NUM>. The QWP <NUM> may be supported by a window of an enclosure, not shown, of the tiltable reflector <NUM>, and may even be supported by the tiltable reflector <NUM> itself, or may be laminated to the reflective polarizer <NUM>.

The multipass coupler <NUM> may further include a second lens element <NUM> having first <NUM> and second <NUM> coaxial optical surfaces, the first optical surface <NUM> facing the first lens element <NUM>. A side face <NUM> may be disposed between the first <NUM> and second <NUM> optical surfaces for inputting the light beam <NUM> provided by the light source <NUM> into the second lens element <NUM>. A buried turn mirror <NUM> may be disposed within the second lens element <NUM> in an optical path of the light beam <NUM> inputted through the side face <NUM> of the second lens element <NUM>, for turning the light beam <NUM> towards the first optical surface <NUM> of the second lens element <NUM> and further through the first lens element <NUM>.

The light beam <NUM> propagates through the side face <NUM> and is reflected by the buried turn mirror <NUM>. Then, the light beam <NUM> propagates in sequence through the first surface <NUM> of the second lens element <NUM>, through the first lens element <NUM>, impinges onto and gets reflected by the tiltable reflector <NUM>, is reflected by the reflective polarizer <NUM> to impinge onto and get reflected by the tiltable reflector <NUM> once again, propagates through the first lens element <NUM>, propagates through the second lens element <NUM>, and impinges onto the exit pupil of the multipass scanner <NUM> located at the pupil-replicating waveguide <NUM>. The first <NUM> and second <NUM> lens elements surfaces may be optimized to provide the necessary collimation of the light beam <NUM> at the pupil-replicating waveguide <NUM>. The above described optical path is defined by the position and orientation of the reflective polarizer <NUM> and the QWP <NUM>, which are disposed in a configuration similar to one described above with reference to <FIG>.

Referring to <FIG>, a near-eye display <NUM> includes a multipass scanner <NUM> coupled to a pupil-replicating waveguide <NUM>. The multipass scanner <NUM> includes a light source <NUM>, a tiltable reflector <NUM>, e.g. a packaged MEMS tiltable reflector having a window <NUM>, and a multipass coupler <NUM>. Similarly to the multipass coupler <NUM> of <FIG> and the multipass coupler <NUM> of <FIG>, the multipass coupler <NUM> of <FIG> to 6R employs a polarization-based double reflection configuration of <FIG>, in that it includes a reflective polarizer <NUM> 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 <NUM> disposed in an optical path between the reflective polarizer <NUM> and the tiltable reflector <NUM>.

The multipass coupler <NUM> further includes a polarization beamsplitter (PBS) <NUM> for reflecting light having the first polarization state and transmitting light having the second polarization state, and first <NUM> and second <NUM> curved reflectors proximate adjoining surfaces of the PBS <NUM> for reflecting the light beam exiting the PBS <NUM> back towards the PBS <NUM>. The first curved reflector <NUM> and the reflective polarizer <NUM> may be disposed on opposite sides of the PBS <NUM>, i.e. below and above the PBS <NUM> in <FIG>, and the second curved reflector <NUM> and the tiltable reflector <NUM> may be disposed on other opposite sides of the PBS <NUM>, i.e. to the right and to the left of the PBS <NUM>. The first curved reflector <NUM> and the second curved reflector <NUM> may each include a concave lens with a reflective coating on its distal (i.e. farthest from the PBS <NUM>) convex surface. The reflective coating may include several coatings spaced apart in a direction of the optical axis of the reflector. Some of these coatings may be dichroic to selectively reflect light of a particular color channel of the image to be displayed. Such a configuration may be used to compensate for chromatic aberrations in the system.

The multipass coupler <NUM> further includes a second QWP <NUM> disposed in an optical path between the PBS <NUM> and the first curved reflector <NUM> and configured to convert a polarization state of light between the first and second polarization states upon a double-pass propagation through the second QWP <NUM>, and a third QWP <NUM> disposed in an optical path between the PBS <NUM> and the second curved reflector <NUM> and configured to convert a polarization state of light between the first and second polarization states upon a double-pass propagation through the third QWP <NUM>. The multipass coupler <NUM> may further include a first lens element <NUM> in an optical path between the PBS <NUM> and the tiltable reflector <NUM>, and a second lens element <NUM> in an optical path between the PBS <NUM> and the reflective polarizer <NUM>. The light propagation through the multipass coupler <NUM> involves seven passes through the PBS <NUM> and will be considered below in several steps depicted sequentially in <FIG>, <FIG>, and <FIG>.

The first three passes of a light beam <NUM> emitted by the light source <NUM> through the PBS <NUM> are illustrated in <FIG>. Herein an in <FIG>, the first polarization state is a linear polarization state oriented perpendicular to <FIG>, and the second polarization state is a linear polarization state oriented in-plane of <FIG>. The light beam <NUM> emitted by the light source <NUM> (<FIG>) is circularly polarized. The light beam <NUM> is focused to propagate through an opening <NUM> in the first curved reflector <NUM>. Then, the light beam <NUM> propagates through the second QWP <NUM>, impinges, while in the first polarization state, onto the PBS <NUM>, is reflected by the PBS <NUM> towards the tiltable reflector <NUM>, propagates through the first QWP <NUM>, is reflected by the tiltable reflector <NUM> for the first time, propagates again through the first QWP <NUM> thereby converting to the second polarization state, propagates through the PBS <NUM> and the third QWP <NUM>, impinges onto the second curved reflector <NUM>, propagates again through the third QWP <NUM> thereby converting back to the first polarization state, and is accordingly reflected by the PBS <NUM> towards the reflective polarizer <NUM>.

The next two passes of the light beam <NUM> through the PBS <NUM> are illustrated in <FIG>. The light beam <NUM> reflected by the PBS <NUM> towards the reflective polarizer <NUM> in the first polarization state propagates back towards the PBS <NUM> as shown, is reflected by the PBS <NUM> towards the second curved reflector <NUM>, propagates through the third QWP <NUM>, is reflected by the second curved reflector <NUM> to propagate again through the third QWP <NUM> thereby converting to the second polarization state, propagates through the PBS <NUM>, through the first QWP <NUM>, and is reflected by the tiltable reflector <NUM> for the second time towards the PBS <NUM>.

The final two passes of the light beam <NUM> through the PBS <NUM> are illustrated in <FIG>. The light beam <NUM> reflected y the tiltable reflector <NUM> for the second time propagates again through the first QWP <NUM> thereby converting to the first polarization state, is reflected by the PBS <NUM> to the first curved reflector <NUM>, propagates through the second QWP <NUM>, is reflected by the first curved reflector <NUM>, propagates again through the second QWP <NUM> thereby converting to the second polarization state, propagates through PBS <NUM>, and propagates through the reflective polarizer <NUM> to the exit pupil located proximate the pupil-replicating waveguide <NUM>.

The entire optical path of the light beam <NUM> in the near-eye display <NUM> is illustrated in <FIG>. <FIG> shows the entire optical path of a chief ray <NUM> of the light beam <NUM>. In summary, the chief ray <NUM> passes through one cube-width of optical path seven times. The first three passes through the cube are depicted in <FIG>, the following two passes are depicted in <FIG>, and the final two passes are depicted in <FIG>. Further, the pupil of tiltable reflector <NUM> is relayed first to a reflective polarizer <NUM>, then relayed back onto itself (doubling the reflected angle), then relayed back to the reflective polarizer <NUM>, this time transmitting to the pupil-replicating waveguide <NUM>.

The multipass couplers <NUM> of <FIG>, <NUM> of <FIG>, and <NUM> of <FIG> perform similar functions of firstly, coupling the light beam emitted by the light source to the tiltable reflector; secondly, coupling the light beam reflected by the tiltable reflector back to the tiltable reflector; and thirdly, coupling the light beam reflected multiple times from the tiltable reflector to the exit pupil, or to the pupil-replicating waveguide. Accordingly, the above multipass couplers may be described as each having a first coupler portion responsible for coupling light provided by the light source to the tiltable reflector; a second coupler portion for coupling light reflected by the tiltable reflector back to the tiltable reflector; and a third coupling portion for coupling light reflected multiple times from the tiltable reflector to the exit pupil. Different portions of the multipass couplers may share same optical elements. This is illustrated in <FIG> considered below.

Referring first to <FIG> with further reference to <FIG>, <FIG>, a multipass coupler <NUM> (<FIG>) is representative of the multipass coupler <NUM> of <FIG> and the multipass coupler <NUM> of <FIG>. A first portion <NUM> (<FIG>) of the multipass coupler <NUM> couplers light provided by a light source <NUM> to a tiltable reflector <NUM>, which is shown in <FIG> tilted by an angle of tilt α. The first portion <NUM> may include e.g. the opening <NUM> in the pupil-replicating waveguide <NUM>, and the first <NUM> and second <NUM> lens elements (<FIG>); or the buried turning mirror <NUM> and the first <NUM> and second <NUM> lens elements (<FIG>). A second portion <NUM> (<FIG>) couples light reflected by the tiltable reflector <NUM> at twice the angle of tilt α back to the tiltable reflector <NUM>. The light is coupled by a reflector reflecting the light from the tiltable reflector <NUM> back towards the tiltable reflector <NUM>. For example, the reflective polarizer <NUM> (<FIG>) reflects the light beam <NUM> back towards the tiltable reflector <NUM>; and the reflective polarizer <NUM> of <FIG>) reflects the light beam <NUM> back towards the tiltable reflector <NUM>. A third portion <NUM> (<FIG>) of the multipass coupler <NUM> couples the light reflected for the second time at four times the angle of tilt α to the exit pupil located proximate a pupil-replicating waveguide <NUM>. The third portion <NUM> may also include the first <NUM> and second <NUM> lens elements (<FIG>); and the first <NUM> and second <NUM> lens elements (<FIG>).

Referring now to <FIG> with further reference to <FIG>, a multipass coupler <NUM> (<FIG>) is representative of the multipass coupler <NUM> of <FIG>. A first portion <NUM> of the multipass coupler <NUM> (<FIG>) couplers light provided by a light source <NUM> to a tiltable reflector <NUM>, which is shown in <FIG> tilted by the angle of tilt α. The first portion <NUM> may include e.g. the opening <NUM> in first curved reflector <NUM>, the PBS <NUM>, and the first lens element <NUM> (<FIG>). A second portion <NUM> (<FIG>) couples light <NUM>* reflected by the tiltable mirror at twice the angle of tilt α back to a same location on the tiltable mirror <NUM>. In the multipass coupler <NUM>, the light is coupled by a pupil auto-relay relaying the light <NUM>* reflected by the tiltable reflector <NUM> for the first time back to the same location on the tiltable reflector <NUM>. The pupil auto-relay is represented in the multipass coupler <NUM> of <FIG> and <FIG> by the first lens element <NUM>; the PBS <NUM>; the second curved reflector <NUM> and the second lens element <NUM>, which returns the light beam <NUM> to a same location on the tiltable reflector <NUM>. A third portion <NUM> (<FIG>) of the multipass coupler <NUM> couples the light reflected for the second time at four times the angle of tilt α to the exit pupil. The third portion <NUM> may also include the first lens element <NUM>, the PBS <NUM>, the first curved reflector <NUM>, and the second lens element <NUM> (<FIG>). The third portion <NUM> is also a pupil relay, and as such it returns the light at four times the angle of tilt α back to a same location as at zero angle of tilt. Using the pupil relay(s) and/or pupil auto relay(s) is advantageous, because it allows one to reduce the size of the tiltable mirrors <NUM>, <NUM> and the size of grating in-couplers of the pupil-replicating waveguides <NUM>, <NUM>.

Referring to <FIG>, a near-eye display <NUM> not according to the claimed invention includes a first light source <NUM> for providing a first light beam <NUM> and a second light source <NUM> for providing a second light beam <NUM>. A tiltable reflector <NUM> is configured for reflecting the first <NUM> and second <NUM> light beams at a variable angle. A pupil-replicating waveguide <NUM> is configured to receive the first <NUM> and second <NUM> light beams tilted by the tiltable reflector <NUM>, and expanding the first <NUM> and second <NUM> light beams over an eyebox <NUM> by providing multiple portions of the first <NUM> and second <NUM> light beams over the eyebox <NUM>, thus enabling a user of the near-eye display <NUM> to comfortably view the image in angular domain provided by the near-eye display <NUM>. The pupil-replicating waveguide <NUM> includes a polarization-selective in-coupler <NUM> for in-coupling light in a first polarization state into the pupil-replicating waveguide <NUM> while transmitting through light in a second polarization state orthogonal to the first polarization state.

The near-eye display <NUM> further includes a first curved reflector <NUM> configured to receive the first light beam <NUM> from the first light source <NUM> and reflect the first light beam <NUM> in the second polarization state towards the tiltable reflector <NUM> and through the polarization-selective in-coupler <NUM>. Since the first light beam <NUM> generated by the first light source <NUM> is in the second polarization state, the first light beam <NUM> propagates through the in-coupler <NUM> substantially without coupling into the pupil-replicating waveguide <NUM>.

Similarly, a second curved reflector may be configured for receiving the second light beam <NUM> from the second light source <NUM> and reflecting the second light beam <NUM> in the second polarization state towards the tiltable reflector <NUM> and through the polarization-selective in-coupler <NUM> substantially without coupling into the pupil-replicating waveguide <NUM>. The first <NUM> and second <NUM> light sources are disposed on an opposite side of the pupil-replicating waveguide from the first <NUM> and second <NUM> curved reflectors. The first <NUM> and second <NUM> curved reflectors may be constructed similarly to the curved reflectors <NUM> and <NUM> of <FIG>.

Upon reflection from the tiltable reflector, the first and second light beams convert to the first polarization state. The conversion may be facilitated by dedicated polarization conversion element(s) disposed in the optical path between the tiltable reflector <NUM> and the pupil-replicating waveguide <NUM>. In some embodiments, the conversion may occur even without polarization-converting elements. For example, in embodiments where the first and second polarization states are circular polarization states of opposite handedness, the conversion from the second to first polarization state occurs upon reflection from the tiltable reflector <NUM>, or any reflector for tat matter, because upon reflection, the phase relationship between the X- and Y-components of the optical electric field is preserved, while the direction of propagation is reversed, thereby changing the handedness of the circular polarization to an opposite handedness. Due to this, the first <NUM> and second <NUM> light beams are in-coupled by the in-coupler <NUM> into the pupil-replicating waveguide <NUM>.

The first <NUM> and second <NUM> light beams generated by the first <NUM> and second <NUM> light sources, respectively, are scanned over different portions of the field of view (FOV) of the near-eye display <NUM>, thereby expanding the overall FOV. The portions of the FOV may overlap thereby providing an area of redundancy, which may be used to provide an increased spatial resolution, overall brightness, etc..

Referring to <FIG>, a near-eye display <NUM> is similar to the near-eye display <NUM> of <FIG>, and includes similar elements, e.g. a pupil-replicating waveguide <NUM>, a tiltable mirror <NUM>, etc. The near-eye display <NUM> of <FIG> includes not two but four light sources <NUM>, <NUM>, <NUM>, <NUM> for providing not two but four light beams <NUM>, <NUM>, <NUM>, and <NUM> reflected by tiltable reflectors <NUM>, <NUM>, <NUM>, and <NUM> respectively and scanned by the tiltable reflector <NUM> over their corresponding FOV portions.

Turning to <FIG>, a near-eye display <NUM> is similar to the near-eye display <NUM> of <FIG> and includes similar elements, i.e. light sources <NUM> and <NUM>, a pupil-replicating waveguide <NUM> having a polarization-selective input coupler <NUM>, curved reflectors <NUM> and <NUM>, and a tiltable reflector <NUM> for reflecting at a variable angle light beams <NUM> and <NUM> emitted by the light sources <NUM> and <NUM>, respectively, and collimated by curved reflectors <NUM> and <NUM>, respectively. The near-eye display <NUM> of <FIG> further includes folding mirrors <NUM> and <NUM> disposed in an optical path between the light sources <NUM> and <NUM> and the curved reflectors <NUM> and <NUM>, respectively. The folding mirrors <NUM> and <NUM> enable the light sources <NUM> and <NUM> to be disposed on a same side of the pupil-replicating waveguide as the curved reflectors <NUM> and <NUM>, thereby reducing the number of passes of the light beams <NUM> and <NUM> through the pupil-replicating waveguide <NUM>. The light sources <NUM> and <NUM> may each include a group of individual emitters (Source Group <NUM> and Source Group <NUM>, respectively); for that matter, the light sources <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> and <NUM> of <FIG>, and <NUM>, <NUM>, <NUM>, and <NUM> of <FIG> may also each include a plurality of emitters. Several emitters may be provided for each color channel.

Referring to <FIG>, four red emitters 1200R may be provided for red (R) color channel (dark-shaded circles); four green emitters <NUM> may be provided for green (G) color channel (medium-shaded circles); and four blue emitters 1200B may be provided for blue (B) color channel (light-shaded circles). The emitters 1200R, <NUM>, and 1200B may each be ridge emitters sharing a common semiconductor substrate. The emitters 1200R, <NUM>, and 1200B may be disposed in a line pattern (<FIG>); in a zigzag pattern (<FIG>); or in a honeycomb pattern (<FIG>), to name just a few examples.

Having a plurality of emitters illuminating a same tiltable reflector enables the scanning of the light beams generated by the emitters to be performed together as a group. When a light source includes a plurality of individual emitters, the illuminating light beam includes a plurality of sub-beams co-propagating at a slight angle w. t each other. Maximum angular cone of the sub-beams may be less than <NUM> degrees, or less than <NUM> degrees, or less than <NUM> degree in some embodiments. Multiple emitters and, in some cases, multiple light sources may be used to provide redundancy in case some of light sources fail, increase image resolution, increase overall image brightness, etc. Multiple light sources may each be equipped with its own collimator.

The near-eye displays <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, and <NUM> of <FIG> provide a low-obliquity coupling of light beam(s) to a tiltable reflector. Herein, the term "low obliquity" means a low angle of incidence, i.e. a normal incidence, at the tiltable reflector when in a nominal, e.g. a center or zero, angle of tilt. One advantage of having low obliquity is illustrated in <FIG>. Referring first to <FIG>, an aspect ratio of a FOV of a projector using a tiltable reflector is plotted as a function of obliquity, i.e. angle of incidence at the tiltable reflector when in nominal or center position. The aspect ratio is plotted for four cases: <NUM> degrees by <NUM> degrees on-axis FOV; <NUM> degrees by <NUM> degrees on-axis FOV; <NUM> degrees by <NUM> degrees on-axis FOV; and <NUM> degrees by <NUM> degrees on-axis FOV. The aspect ratio drops from <NUM> at zero obliquity, i.e. normal incidence, to about <NUM> at <NUM> degrees obliquity angle.

<FIG> shows a zero-obliquity scanning angular area 1300B and an associated inscribed rectangular FOV 1302B. The zero-obliquity FOV 1302B solid angle is covering most of the angular area 1300B. By comparison, <FIG> shows a <NUM> degrees obliquity scanning angular area 1300C and an associated inscribed rectangular FOV 1302C. The FOV 1302C solid angle occupies a smaller percentage of the angular area 1300C, and is almost <NUM> times less than the zero-obliquity FOV 1302B, and has a different aspect ratio. Thus, the low-obliquity coupling improves the utilization of the scanning range of the tiltable reflector, enabling wider fields of view at the same scanning range of the tiltable reflector. It is to be noted that the tiltable reflector <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, and <NUM> of <FIG> may be implemented as a MEMS tiltable reflectors.

Embodiments of the present disclosure may include, or be implemented in conjunction with, an artificial reality system. An artificial reality system adjusts sensory information about outside world obtained through the senses such as visual information, audio, touch (somatosensation) information, acceleration, balance, etc., in some manner before presentation to a user. By way of non-limiting examples, artificial reality may include virtual reality (VR), augmented reality (AR), mixed reality (MR), hybrid reality, or some combination and/or derivatives thereof. Artificial reality content may include entirely generated content or generated content combined with captured (e.g., real-world) content. The artificial reality content may include video, audio, somatic or haptic feedback, or some combination thereof. Any of this content may be presented in a single channel or in multiple channels, such as in a stereo video that produces a three-dimensional effect to the viewer. Furthermore, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, that are used to, for example, create content in artificial reality and/or are otherwise used in (e.g., perform activities in) artificial reality. The artificial reality system that provides the artificial reality content may be implemented on various platforms, including a wearable display such as an HMD connected to a host computer system, a standalone HMD, a near-eye display having a form factor of eyeglasses, a mobile device or computing system, or any other hardware platform capable of providing artificial reality content to one or more viewers.

Referring to <FIG>, an HMD <NUM> is an example of an AR/VR wearable display system which encloses the user's face, for a greater degree of immersion into the AR/VR environment. The HMD <NUM> is an embodiment of the <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, <NUM> of <FIG>, and <NUM> of <FIG>, for example. The function of the HMD <NUM> is to augment views of a physical, real-world environment with computer-generated imagery, and/or to generate the entirely virtual 3D imagery. The HMD <NUM> may include a front body <NUM> and a band <NUM>. The front body <NUM> is configured for placement in front of eyes of a user in a reliable and comfortable manner, and the band <NUM> may be stretched to secure the front body <NUM> on the user's head. A display system <NUM> may be disposed in the front body <NUM> for presenting AR/VR imagery to the user. Sides <NUM> of the front body <NUM> may be opaque or transparent.

In some embodiments, the front body <NUM> includes locators <NUM> and an inertial measurement unit (IMU) <NUM> for tracking acceleration of the HMD <NUM>, and position sensors <NUM> for tracking position of the HMD <NUM>. The IMU <NUM> is an electronic device that generates data indicating a position of the HMD <NUM> based on measurement signals received from one or more of position sensors <NUM>, which generate one or more measurement signals in response to motion of the HMD <NUM>. Examples of position sensors <NUM> include: one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor that detects motion, a type of sensor used for error correction of the IMU <NUM>, or some combination thereof. The position sensors <NUM> may be located external to the IMU <NUM>, internal to the IMU <NUM>, or some combination thereof.

The locators <NUM> are traced by an external imaging device of a virtual reality system, such that the virtual reality system can track the location and orientation of the entire HMD <NUM>. Information generated by the IMU <NUM> and the position sensors <NUM> may be compared with the position and orientation obtained by tracking the locators <NUM>, for improved tracking accuracy of position and orientation of the HMD <NUM>. Accurate position and orientation is important for presenting appropriate virtual scenery to the user as the latter moves and turns in 3D space.

The HMD <NUM> may further include a depth camera assembly (DCA) <NUM>, which captures data describing depth information of a local area surrounding some or all of the HMD <NUM>. To that end, the DCA <NUM> may include a laser radar (LIDAR), or a similar device. The depth information may be compared with the information from the IMU <NUM>, for better accuracy of determination of position and orientation of the HMD <NUM> in 3D space.

The HMD <NUM> may further include an eye tracking system <NUM> for determining orientation and position of user's eyes in real time. The obtained position and orientation of the eyes also allows the HMD <NUM> to determine the gaze direction of the user and to adjust the image generated by the display system <NUM> accordingly. In one embodiment, the vergence, that is, the convergence angle of the user's eyes gaze, is determined. The determined gaze direction and vergence angle may also be used for real-time compensation of visual artifacts dependent on the angle of view and eye position. Furthermore, the determined vergence and gaze angles may be used for interaction with the user, highlighting objects, bringing objects to the foreground, creating additional objects or pointers, etc. An audio system may also be provided including e.g. a set of small speakers built into the front body <NUM>.

Referring to <FIG>, an AR/VR system <NUM> includes the HMD <NUM> of <FIG>, an external console <NUM> storing various AR/VR applications, setup and calibration procedures, 3D videos, etc., and an input/output (I/O) interface <NUM> for operating the console <NUM> and/or interacting with the AR/VR environment. The HMD <NUM> may be "tethered" to the console <NUM> with a physical cable, or connected to the console <NUM> via a wireless communication link such as Bluetooth®, Wi-Fi, etc. There may be multiple HMDs <NUM>, each having an associated I/O interface <NUM>, with each HMD <NUM> and I/O interface(s) <NUM> communicating with the console <NUM>. In alternative configurations, different and/or additional components may be included in the AR/VR system <NUM>. Additionally, functionality described in conjunction with one or more of the components shown in <FIG> and <FIG> may be distributed among the components in a different manner than described in conjunction with <FIG> and <FIG> in some embodiments. For example, some or all of the functionality of the console <NUM> may be provided by the HMD <NUM>, and vice versa. The HMD <NUM> may be provided with a processing module capable of achieving such functionality.

As described above with reference to <FIG>, the HMD <NUM> may include the eye tracking system <NUM> (<FIG>) for tracking eye position and orientation, determining gaze angle and convergence angle, etc., the IMU <NUM> for determining position and orientation of the HMD <NUM> in 3D space, the DCA <NUM> for capturing the outside environment, the position sensor <NUM> for independently determining the position of the HMD <NUM>, and the display system <NUM> for displaying AR/VR content to the user. The display system <NUM> includes (<FIG>) an electronic display <NUM>, for example and without limitation, 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 <NUM> further includes an optics block <NUM>, whose function is to convey the images generated by the electronic display <NUM> to the user's eye. The optics block may include various lenses, e.g. a refractive lens, a Fresnel lens, a diffractive lens, an active or passive Pancharatnam-Berry phase (PBP) lens, a liquid lens, a liquid crystal lens, etc., a pupil-replicating waveguide, grating structures, coatings, etc. The display system <NUM> may further include a varifocal module <NUM>, which may be a part of the optics block <NUM>. The function of the varifocal module <NUM> is to adjust the focus of the optics block <NUM> e.g. to compensate for vergence-accommodation conflict, to correct for vision defects of a particular user, to offset aberrations of the optics block <NUM>, etc..

The I/O interface <NUM> is a device that allows a user to send action requests and receive responses from the console <NUM>. An action request is a request to perform a particular action. For example, an action request may be an instruction to start or end capture of image or video data or an instruction to perform a particular action within an application. The I/O interface <NUM> 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 communicating the action requests to the console <NUM>. An action request received by the I/O interface <NUM> is communicated to the console <NUM>, which performs an action corresponding to the action request. In some embodiments, the I/O interface <NUM> includes an IMU that captures calibration data indicating an estimated position of the I/O interface <NUM> relative to an initial position of the I/O interface <NUM>. In some embodiments, the I/O interface <NUM> may provide haptic feedback to the user in accordance with instructions received from the console <NUM>. For example, haptic feedback can be provided when an action request is received, or the console <NUM> communicates instructions to the I/O interface <NUM> causing the I/O interface <NUM> to generate haptic feedback when the console <NUM> performs an action.

The console <NUM> may provide content to the HMD <NUM> for processing in accordance with information received from one or more of: the IMU <NUM>, the DCA <NUM>, the eye tracking system <NUM>, and the I/O interface <NUM>. In the example shown in <FIG>, the console <NUM> includes an application store <NUM>, a tracking module <NUM>, and a processing module <NUM>. Some embodiments of the console <NUM> may have different modules or components than those described in conjunction with <FIG>. Similarly, the functions further described below may be distributed among components of the console <NUM> in a different manner than described in conjunction with <FIG> and <FIG>.

The application store <NUM> may store one or more applications for execution by the console <NUM>. An application is a group of instructions that, when executed by a processor, generates content for presentation to the user. Content generated by an application may be in response to inputs received from the user via movement of the HMD <NUM> or the I/O interface <NUM>. Examples of applications include: gaming applications, presentation and conferencing applications, video playback applications, or other suitable applications.

The tracking module <NUM> may calibrate the AR/VR system <NUM> using one or more calibration parameters and may adjust one or more calibration parameters to reduce error in determination of the position of the HMD <NUM><NUM> or the I/O interface <NUM>. Calibration performed by the tracking module <NUM> also accounts for information received from the IMU <NUM> in the HMD <NUM><NUM> and/or an IMU included in the I/O interface <NUM>, if any. Additionally, if tracking of the HMD <NUM><NUM> is lost, the tracking module <NUM> may re-calibrate some or all of the AR/VR system <NUM>.

The tracking module <NUM> may track movements of the HMD <NUM><NUM> or of the I/O interface <NUM>, the IMU <NUM>, or some combination thereof. For example, the tracking module <NUM> may determine a position of a reference point of the HMD <NUM><NUM> in a mapping of a local area based on information from the HMD <NUM><NUM>. The tracking module <NUM> may also determine positions of the reference point of the HMD <NUM><NUM> or a reference point of the I/O interface <NUM> using data indicating a position of the HMD <NUM><NUM> from the IMU <NUM> or using data indicating a position of the I/O interface <NUM> from an IMU included in the I/O interface <NUM>, respectively. Furthermore, in some embodiments, the tracking module <NUM> may use portions of data indicating a position or the HMD <NUM><NUM> from the IMU <NUM> as well as representations of the local area from the DCA <NUM> to predict a future location of the HMD <NUM>. The tracking module <NUM> provides the estimated or predicted future position of the HMD <NUM> or the I/O interface <NUM> to the processing module <NUM>.

The processing module <NUM> may generate a 3D mapping of the area surrounding some or all of the HMD <NUM> ("local area") based on information received from the HMD <NUM>. In some embodiments, the processing module <NUM> determines depth information for the 3D mapping of the local area based on information received from the DCA <NUM> that is relevant for techniques used in computing depth. In various embodiments, the processing module <NUM> may use the depth information to update a model of the local area and generate content based in part on the updated model.

The processing module <NUM> executes applications within the AR/VR system <NUM> and receives position information, acceleration information, velocity information, predicted future positions, or some combination thereof, of the HMD <NUM> from the tracking module <NUM>. Based on the received information, the processing module <NUM> determines content to provide to the HMD <NUM> for presentation to the user. For example, if the received information indicates that the user has looked to the left, the processing module <NUM> generates content for the HMD <NUM> that mirrors the user's movement in a virtual environment or in an environment augmenting the local area with additional content. Additionally, the processing module <NUM> performs an action within an application executing on the console <NUM> in response to an action request received from the I/O interface <NUM> and provides feedback to the user that the action was performed. The provided feedback may be visual or audible feedback via the HMD <NUM> or haptic feedback via the I/O interface <NUM>.

In some embodiments, based on the eye tracking information (e.g., orientation of the user's eyes) received from the eye tracking system <NUM>, the processing module <NUM> determines resolution of the content provided to the HMD <NUM> for presentation to the user on the electronic display <NUM>. The processing module <NUM> may provide the content to the HMD <NUM> having a maximum pixel resolution on the electronic display <NUM> in a foveal region of the user's gaze. The processing module <NUM> may provide a lower pixel resolution in other regions of the electronic display <NUM>, thus lessening power consumption of the AR/VR system <NUM> and saving computing resources of the console <NUM> without compromising a visual experience of the user. In some embodiments, the processing module <NUM> can further use the eye tracking information to adjust where objects are displayed on the electronic display <NUM> to prevent vergence-accommodation conflict and/or to offset optical distortions and aberrations.

Claim 1:
A near-eye display for providing an image in angular domain at an eyebox, the near-eye display comprising a multipass scanner (<NUM>, <NUM>, <NUM>, <NUM>) for scanning a light beam, the multipass
scanner comprising:
a light source (<NUM>, <NUM>, <NUM>, <NUM>) for providing the light beam;
a tiltable reflector (<NUM>, <NUM>, <NUM>, <NUM>) for reflecting the light beam provided by the light source by tilting the tiltable reflector at a variable angle;
a multipass coupler (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) 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 a 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 a second time and coupling the light beam to an exit pupil of the multipass 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 quarter-wave waveplate (<NUM>, <NUM>, <NUM>, <NUM>), QWP, disposed in an optical path between the reflective polarizer and the tiltable reflector and configured to convert a polarization state of light between the first and second polarization states upon a double-pass propagation through the first QWP,
wherein in operation, the light beam having the first or second polarization state propagates in sequence through the first QWP, impinges onto the tiltable reflector for the first time, is reflected by the tiltable reflector to propagate again through the first QWP thereby converting to the other of the first and second polarization states, is reflected by the reflective polarizer, propagates through the first QWP and impinges onto the tiltable reflector for the second time, is reflected by the tiltable reflector to propagate through the first QWP thereby converting back to the first or second polarization state, and propagates through the reflective polarizer to the exit pupil.