View region selection using electrochromic surfaces

Abstract

To increase a field of view (FOV) area of a head mounted display (HWD), the HWD includes an optical engine (202) configured to emit display light representing one or more images toward a light guide (205) of the HWD. Further, the HWD includes an electrochromic reflector having one or more electrochromic faces (322). The electrochromic faces are configured to guide the display light such that the display light propagates through the light guide along a path of a plurality of paths based on one or more respective states of the electrochromic faces. The FOV area is increased by increasing the number of paths through which the display light propagates through the light guide.

Description

Background Art

[0001] In some head wearable displays (HWD), an image is displayed to the user by coupling a light beam from a projector into an input coupler of a light guide. The input coupler then provides the light beam to the body of the light guide, where the light beam propagates by total internal reflection (TIR). The light beams propagate through the light guide until they are received at the output coupler of the light guide, which is configured to guide the light beam out of the light guide toward the user so that the image is presented to the user within the field of view (FOV) area of ​​the HWD. In order to increase the user's FOV area, some HWDs use a projector that provides additional light beams to the input coupler of the light guide at a greater number of angles. However, in order to provide these additional light beams, the size and power requirements of the projector will increase, which will increase the overall size of the HWD and have a negative impact on the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] By referring to the accompanying drawings, the present disclosure can be better understood, and its numerous features and advantages become apparent to those skilled in the art. The same reference numerals are used in different drawings to indicate similar or identical items.

[0003] Figure 1 is a diagram of an example display system housing a projection system configured to project an image toward an eye of a user, according to some embodiments.

[0004] Figure 2 is a diagram of a projection system that projects an image directly onto a user's eyes via display light, according to some embodiments.

[0005] Figure 3 is a diagram of a projection system including an electrochromic reflector disposed within a light guide according to some embodiments.

[0006] Figure 4 is a diagram of a projection system including an electrochromic reflector having two or more electrochromic facets, according to some embodiments.

[0007] Figure 5 is a diagram of a stacked light guide including an electrochromic reflector according to some embodiments.

[0008] Figure 6 is a diagram of a split exit pupil expander including an electrochromic reflector according to some embodiments.

[0009] Figure 7 Example overlaps of viewing areas provided by electrochromic reflectors according to some embodiments are presented.

[0010] Figure 8Example split portions of the viewing area provided by an electrochromic reflector are presented in accordance with some embodiments.

[0011] Fig. 9 is a diagram showing a partially transparent view of a head mounted display including a projection system according to some embodiments. Summary of the invention

[0012] Techniques and systems described herein are directed to increasing the field of view (FOV) area in a head mounted display (HWD) using an electrochromic reflector. According to an example embodiment, the HWD includes an optical engine configured to emit display light. Further, the HWD may include a light guide and an electrochromic facet. The electrochromic facet may be configured to guide the display light so that the display light propagates through the light guide along one of a plurality of paths based on a state of the electrochromic facet.

[0013] In an embodiment, each of the plurality of paths may correspond to a respective portion of a field of view (FOV) area of ​​the HWD. Further, the electrochromic face may be configured to direct the display light such that the display light propagates through the light guide along a first path of the plurality of paths based on the electrochromic face being in a first state. Furthermore, the display light propagating through the light guide along the first path of the plurality of paths may be configured to illuminate a first portion of the FOV area. Likewise, the first state may include a reflective state and the electrochromic face may be configured to reflect the display light such that the display light propagates through the light guide along the first path of the plurality of paths.

[0014] According to an embodiment, the electrochromic surface may be configured to guide the display light so that the display light propagates through the light guide along a second path among the multiple paths based on the electrochromic surface being in the second state. In addition, the display light propagating through the light guide along the second path among the multiple paths may be configured to illuminate a second portion of the FOV area. Further, the second state may include a transmissive state, and the electrochromic surface may be configured to transmit the display light to the reflective surface. In addition, the reflective surface may be configured to reflect the display light so that the display light propagates through the light guide along the second path among the multiple paths. Within the HWD, the electrochromic surface may be set at a first angle relative to the surface of the light guide, and the reflective surface may be set at a second angle relative to the surface of the light guide. The first angle may be different from the second angle. Further, the HWD may include a mirror control circuit system configured to control the state of the electrochromic surface based on the gaze of the user. In addition, the electrochromic surface may be set within the light guide.

[0015] In another example embodiment, a light guide for a HWD includes one or more electrochromic surfaces configured to guide display light such that the display light propagates through the light guide along a path among a plurality of paths based on one or more corresponding states of the one or more electrochromic surfaces.

[0016] In an embodiment, each of the multiple paths may correspond to a respective portion of the FOV area of ​​the HWD. Further, a first surface of the one or more electrochromic surfaces may be configured to guide display light such that the display light propagates through the light guide along a first path of the multiple paths based on the first electrochromic surface being in a first state. The first state may include a reflective state and the first electrochromic surface may be configured to reflect the display light such that the display light propagates through the light guide along the first path. In addition, the first electrochromic surface may be configured to transmit the display light to a second electrochromic surface of the one or more electrochromic surfaces based on the first electrochromic surface being in a second state. Further, the second electrochromic surface may be configured to guide the display light such that the display light propagates through the light guide along a second path of the multiple paths based on the second electrochromic surface being in the first state.

[0017] Likewise, the second electrochromic facet may be configured to direct the display light such that the display light propagates through the light guide along a third path of the plurality of paths based on the second electrochromic facet being in the second state. Additionally, the one or more corresponding states of the one or more electrochromic facets may be determined by a mirror control circuitry configured to control the one or more corresponding states of the one or more electrochromic facets based on a gaze of a user. The one or more electrochromic facets may be disposed within the light guide.

[0018] In another exemplary embodiment, a method includes emitting display light toward a light guide. The method may further include directing the display light by an electrochromic facet disposed within the light guide such that the display light propagates through the light guide along a path in a plurality of paths based on a state of the electrochromic facet.

[0019] According to an embodiment, within the method, each of the plurality of paths may correspond to a respective portion of the FOV area. Additionally, the method may include directing the display light by the electrochromic surface such that the display light propagates through the light guide along a first path of the plurality of paths based on the electrochromic surface being in a first state. The display light propagating through the light guide along the first path of the plurality of paths may be configured to illuminate a first portion of the FOV area.

[0020] In an embodiment, the method further includes directing the display light by the electrochromic face so that the display light propagates through the light guide along a second path of the plurality of paths based on the electrochromic face being in the second state. The display light propagating through the light guide along the second path of the plurality of paths can be configured to illuminate a second portion of the FOV area. Likewise, the method can include controlling the state of the electrochromic face based on a gaze of the user. DETAILED DESCRIPTION

[0021] Some head mounted displays (HWD) (e.g., extended reality head mounted displays) are designed to look like glasses, wherein at least one of the glasses lenses includes a light guide to guide light to the user's eyes. The combination of lenses and light guides is referred to as an "optical combiner", "optical combined lens" or both. Such light guides include, for example, an exit pupil expander (EPE) and an output coupler, which form and guide light to the user's eyes so that an image is presented to the user within the field of view (FOV) region of the optical combiner. HWDs typically have a frame designed to be worn in front of the user's eyes to allow the user to view both their environment and computer generated content displayed in the FOV region of the optical combiner. Components necessary for the functionality of a typical HWD, such as, for example, an optical engine for projecting computer generated content (e.g., display light representing one or more images), a camera for precisely locating a physical location, a camera for tracking the gaze of the user's eyes, a processor for powering the optical engine, and a power supply are typically housed within the frame of the HWD. Since the volume of the HWD frame to accommodate these components is limited, it is desirable that these components be as small as possible and configured to interact with other components within a very small volume space.

[0022] In order to guide the light to the user's eyes, the optical engine of the HWD is configured to emit display light representing an image toward the input coupler of the light guide. Such an input coupler, for example, includes one or more reflective surfaces (e.g., a structure configured to reflect light), and one or more reflective surfaces provide the received light to the body of the light guide. The light then propagates through the light guide using total internal reflection (TIR), partial internal reflection (PIR), or both, until the light is received at the output coupler of the light guide. For example, the output coupler includes one or more reflective surfaces (e.g., a structure configured to reflect light), which guide the light out of the light guide toward the user's eyes, so that one or more images are presented to the user within the FOV area of ​​the optical combiner. In order to increase the FOV area of ​​the display image of the optical combiner, some HWDs include an optical engine that is configured to provide display light to the light guide at a greater number of angles to increase the FOV area. However, providing display light to the light guide at a greater number of angles requires a significant increase in the size of the optical engine, which in turn increases the size of the HWD and has a negative impact on the user's experience. In addition, the optical engine must consume more power in order to illuminate the increased FOV area. Further, in order to increase the FOV area, some HWDs include one or more scanning mirrors that are configured to redirect display light provided from an optical engine so as to illuminate different portions of the increased FOV area at different times. For example, the scanning mirror is configured to redirect light from the optical engine to a first direction at a first time so that a first portion of the increased FOV area is illuminated, and to redirect light from the optical engine at a second time so that a second portion of the increased FOV area is illuminated. However, including such a scanning mirror within the HWD can also significantly increase the size of the HWD and negatively impact the user experience.

[0023] To this end, the systems and techniques disclosed herein are intended to increase the FOV area of ​​the HWD without significantly increasing the size of the HWD. For example, in order to increase the size of the FOV area of ​​the HWD, the HWD includes a light guide, in which an electrochromic reflector is disposed. The electrochromic reflector, for example, includes one or more electrochromic surfaces, one or more reflective surfaces, or both. These electrochromic surfaces include a structure configured to reflect light when in a reflective state and transmit light when in a transmissive state. In order to control the state of the electrochromic surface, the HWD includes a mirror control circuit system, which is configured to provide a control signal, which sets the state (reflection or transmission) of each electrochromic surface of the electrochromic reflector. Based on the state of one or more electrochromic surfaces, the electrochromic reflector is configured to turn the display light received at the light guide to illuminate the corresponding part of the FOV area. For example, based on the electrochromic surface of the electrochromic reflector being in a reflective state, the electrochromic surface is configured to reflect and turn the display light received at the light guide so that the display light propagates through the light guide using a first path and illuminates the first part of the FOV area. Further, based on the electrochromic surface of the electrochromic reflector being in a transmissive state, the electrochromic surface is configured to transmit the display light to the reflective surface, which reflects the display light so that the display light propagates through the light guide using a second path and illuminates a second portion of the FOV area. In this way, the electrochromic reflector increases the size of the FOV area by increasing the number of paths for the display light to propagate through the light guide without increasing the power requirements of the optical engine, because only a portion of the increased FOV area is illuminated at a time. Further, since the electrochromic reflector is disposed within the light guide, the size of the FOV area is increased without increasing the size of the HWD, thereby improving the user experience.

[0024] Figure 1An example display system 100 is shown having a support structure 102 that includes an arm 104 housing a projection system configured to project an image toward a user's eyes such that the user perceives the projected image as being displayed in a FOV area 106 of the display at one or both of lens elements 108, 110. In the depicted embodiment, the display system 100 is a HWD that includes a support structure 102 configured to be worn on a user's head and has the general shape and appearance of an eyeglass frame or sunglass frame. The support structure 102 contains or otherwise includes various components such as a projector (e.g., an optical engine) and a light guide to facilitate projecting such images toward the user's eyes. In some embodiments, the support structure 102 further includes various sensors, such as one or more front-facing cameras, rear-facing cameras, other light sensors, motion sensors, accelerometers, and the like. The support structure 102 may further include one or more radio frequency (RF) interfaces or other wireless interfaces, such as a Bluetooth interface, a Wi-Fi interface, and the like. Additionally, in some embodiments, support structure 102 further includes one or more batteries or other portable power sources for supplying power to the electrical components of display system 100. In some embodiments, some or all of these components of display system 100 are fully or partially contained within an interior volume of support structure 102, such as within frame 104 in region 112 of support structure 102. It should be noted that while example form factors are depicted, it should be understood that in other embodiments, display system 100 may have a form factor similar to that of a display system 100. Figure 1 The eyeglass frames depicted in the picture have different shapes and looks.

[0025] The display system 100 uses one or both of the lens elements 108, 110 to provide an extended reality (XR) display, in which rendered graphical content may be superimposed on or otherwise provided in conjunction with a real-world view perceived by a user through the lens elements 108, 110. For example, display light used to form a perceptible image or series of images may be projected (e.g., emitted) by a projector of the display system 100 via a series of optical elements (such as a light guide at least partially formed in the corresponding lens element) onto an eye of a user. Thus, one or both of the lens elements 108, 110 include at least a portion of a light guide that routes display light received by an input coupler of the light guide to an output coupler of the light guide, which outputs the display light toward an eye of a user of the display system 100. The display light is modulated onto the user's eye such that the user perceives the display light as an image. In addition, each of the lens elements 108, 110 is sufficiently transparent to allow a user to see through the lens elements to provide a FOV area 106 of the user's real world environment, such that the image appears to be superimposed on at least a portion of the real world environment. In an embodiment, to help expand the FOV area 106, the display system 100 includes an electrochromic reflector that is configured to provide light into the light guide such that the FOV area 106 is expanded. For example, the electrochromic reflector is configured to reflect light along different paths within the light guide to increase the FOV area 106. According to an embodiment, the electrochromic reflector is configured to reflect light that propagates through the light guide along a path determined by a state of one or more electrochromic facets within the electrochromic reflector, a liquid crystal display (LCD) within the electrochromic reflector, or both.

[0026] In some embodiments, the projector is a digital light processing based projector, a micro-projector, a scanning laser projector, or any combination of a modulated light source (such as a laser or one or more LEDs) and a dynamic reflector mechanism (such as one or more dynamic scanners or digital light processors). In some embodiments, the projector includes a plurality of laser diodes (e.g., a red laser diode, a green laser diode, and / or a blue laser diode). The projector is communicatively coupled to a controller and a non-transitory processor-readable storage medium or memory storing processor-executable instructions and other data that, when executed by the controller, causes the controller to control the operation of the projector.

[0027] Figure 2A simplified block diagram of a projection system 200 is shown that projects an image directly onto a user's eye via display light. The projection system 200 includes an optical engine 202 and a light guide 205. The term "light guide" as used herein should be understood to mean a combiner that uses one or more of total internal reflection (TIR), partial internal reflection (PIR), specialized filters, and / or reflective surfaces to pass light from an input coupler (such as input coupler 214) to an output coupler (such as output coupler 216). In some display applications, the light is a collimated image, and the light guide passes the collimated image to the eye and reproduces the collimated image. In some embodiments, the projection system 200 is used in a WHD or other display system (such as Figure 1 is implemented in a display system 100).

[0028] The optical engine 202 includes one or more display light sources configured to generate and output display light 218 representing an image (e.g., visible display light such as red display light, blue display light, and green display light and / or invisible display light such as infrared display light). In some embodiments, the optical engine 202 is coupled to a driver or other controller (not shown) that controls the timing of emitting display light from the display light source of the optical engine 202 according to instructions received by the controller or driver from a computer processor coupled thereto to modulate the display light 218 so as to be perceived as an image when output to the retina of the user's eye 220. For example, during operation of the projection system 200, a plurality of display light beams, each having a different wavelength, are output by the display light source of the optical engine 202, and then combined via a beam combiner (not shown) before being directed toward the user's eye 220. The optical engine 202 modulates the respective intensities of the display light beams so that the combined display light reflects a series of pixels of an image, wherein the specific intensity of each display light beam at any given point in time contributes to the amount of corresponding color content and brightness in the pixel represented by the combined display light at that time.

[0029] Further, the light guide 205 includes an input coupler 214 and an output coupler 216, wherein in this example, the output coupler 216 is optically aligned with the user's eye 220. In some embodiments, the input coupler 214 has a substantially rectangular, circular, elliptical profile and is configured to receive the display light 218 and guide the display light 218 into the light guide 205. To this end, the input coupler 214 includes one or more reflective surfaces configured to reflect and guide the display light 218 into the light guide 205. Such reflective surfaces, for example, include one or more structures disposed within the light guide 205, each structure having one or more reflective surfaces, reflective coatings, mirrors (e.g., dielectric mirrors, metal mirrors, Bragg surfaces), mirror coatings, or any combination thereof. According to an embodiment, in response to receiving the display light 218, the input coupler 214 is configured to provide the display light 218 to the light guide 205, such that the display light 218 propagates through the light guide 205 via TIR until it is received by the output coupler 216. As an example, the input coupler 214 provides the display light 218 to the light guide 205, so that the display light 218 bounces one or more times (e.g., reflects from the surface of the light guide 205) before being received by the output coupler 216. After receiving the display light 218, the output coupler 216 is configured to guide the display light 218 out of the light guide 205 toward the user's eye 220. For example, the output coupler 216 includes one or more reflective surfaces that are configured to reflect and guide the display light 218 out of the light guide 205 toward the user's eye 220, so that one or more images are displayed in the FOV area 106. Such reflective surfaces include, for example, one or more structures disposed within the light guide 205, each structure having one or more reflective surfaces, reflective coatings, mirrors (e.g., dielectric mirrors, metal mirrors, Bragg surfaces), mirror coatings, or any combination thereof. In an embodiment, the display light 218 guided out of the light guide 205 by the output coupler 216 forms an exit pupil at a location close to the user's eye 220. For example, the exit pupil includes an image of the display light 218 emitted by the optical engine 202, and refers to the location where two or more beams of the display light 218 along the optical path intersect. As an example, the width (e.g., smallest dimension) of a given exit pupil corresponds approximately to the diameter of the display light 218 corresponding to the exit pupil. Thus, the exit pupil can be considered a "virtual aperture."

[0030] Despite Figure 2205 , the light guide 205 may be coupled to the output coupler 216, the output coupler 216, and / or the eye 220. In some embodiments, an electrochromic reflector is used to direct light into the input coupler 214 so that the light is coupled into the input coupler 214 at an appropriate angle to facilitate propagation of the light in the light guide 205 by TIR. In addition, in some embodiments, an exit pupil expander (EPE), such as a fold grating, is arranged in an intermediate stage between the input coupler 214 and the output coupler 216 to receive light coupled into the light guide 205 by the input coupler 214, expand the light, and redirect the light toward the output coupler 216, which then couples the display light out of the waveguide 205 (e.g., toward the eye 220 of the user).

[0031] Reference now Figure 3 , presents a projection system 300 including an electrochromic reflector disposed within a light guide. According to an embodiment, the projection system 300 is similar or identical to the projection system 200, and in some embodiments, is used in a HWD or other display system (such as Figure 1 The projection system 300 is implemented in the display system 100). In the projection system 300, the light guide 205 has a first surface 301 (e.g., a surface facing the user) and a second surface 303 (e.g., a surface facing the world) opposite to the first surface 301. Further, the light guide 205 includes an electrochromic reflector 328 disposed in the light guide 205, and the electrochromic reflector includes one or more electrochromic surfaces 322. The electrochromic surface 322 includes a structure that is configured to reflect received light when in a first state (e.g., a reflective state) and transmit light when in a second state (e.g., a transmissive state). As an example, the electrochromic surface 322 includes one or more electrochromic layers, each of which is disposed on a structure (e.g., a surface) of the light guide and is configured to reflect light when a first current is applied to the electrochromic layer and transmit light when a second current different from the first current is applied to the electrochromic layer. As another example, the electrochromic surface 322 includes an LCD that is configured to reflect light when a first current is applied to the LCD and transmit light when a second current different from the first current is applied to the LCD. Figure 3The example embodiments presented in the drawings illustrate the electrochromic reflector 328 as including one electrochromic surface 322, but in other embodiments, the electrochromic reflector 328 may include any number of electrochromic surfaces 322. Additionally, in some embodiments, the electrochromic reflector 328 includes one or more reflective surfaces 324. The reflective surface 324, for example, includes one or more structures configured to reflect received light, such as one or more reflective surfaces, reflective coatings, mirrors (e.g., dielectric mirrors, metal mirrors, Bragg surfaces), mirror coatings, or any combination thereof. Although Figure 3 The example embodiment presented in illustrative embodiments shows the electrochromic reflector 328 as including one reflective surface 324 , but in other embodiments, the electrochromic reflector 328 may include any number of reflective surfaces 324 .

[0032] To control the state of one or more electrochromic surfaces 322 of the electrochromic reflector 328, the projection system 300 includes a mirror control circuit system 326. The mirror control circuit system 326 is configured to provide one or more control signals 325 to the one or more electrochromic surfaces 322 of the electrochromic reflector 328, and is configured to change the state of the electrochromic surface 322 by changing one or more of the control signals 325 provided to the electrochromic surface 322. That is, the mirror control circuit system 326 is configured to control the state of the one or more electrochromic surfaces 322 by providing one or more control signals 325 to the electrochromic surface 322. Such control signals 325, for example, represent a voltage, a current, or both provided to the electrochromic surface 322. As an example, in response to the mirror control circuit system 326 providing the control signal 325 representing a first current to the electrochromic surface 322, the electrochromic surface 322 is configured to enter a first state (e.g., a reflective state). Further, in response to mirror control circuitry 326 providing a control signal 325 indicative of a second current different from the first current, electrochromic face 322 is configured to enter a second state (eg, a transmissive state).

[0033] In an embodiment, the projection system 300 includes an optical engine 202 that emits display light 218 representing one or more images toward a first surface 301 of a light guide 205. After the display light 218 passes through the first surface 301 of the light guide 205, it is received by an electrochromic reflector 328 disposed within the light guide 205. According to an embodiment, the electrochromic reflector 328 is configured to guide the display light 218 such that the display light 218 propagates within the light guide 205 via TIR based on a state of one or more electrochromic surfaces 322 of the electrochromic reflector 328. As an example, when the electrochromic surface 322 of the electrochromic reflector 328 is in a first state (e.g., a reflective state), the electrochromic reflector 328 is configured to guide the display light 218 such that the display light 218 propagates through the light guide 205 along a first path 305. Figure 3 In the example embodiment presented, for example, after the display light 218 passes through the first surface 301 of the light guide 205, the display light 218 is received by the electrochromic facet 322. In an embodiment, the electrochromic facet 322 is disposed within the light guide 205 such that the electrochromic facet 322 has an angle θ1 345 relative to the surface 301 of the light guide 205. Since the electrochromic facet 322 is in a first state (e.g., a reflective state), the electrochromic facet 322 is configured to reflect the display light 218 based on the angle θ1 345 of the electrochromic facet 322. For example, the electrochromic facet 322 is configured to reflect the display light 218 such that the display light 218 propagates through the light guide 205 along a first path 305. According to an embodiment, the first path 305 is associated with a first portion of the FOV area 106 to be illuminated. That is, the display light 218 propagating through the light guide 205 along the first path 305 is configured to illuminate the first portion of the FOV area 106.

[0034] As another example, based on the electrochromic face 322 of the electrochromic reflector 328 being in the second state (e.g., the transmissive state), the electrochromic reflector 328 is configured to direct the received light (e.g., the display light 218) such that the received light propagates through the light guide 205 along a second path. Figure 3In the example embodiment presented, for example, after the display light 218 passes through the first surface 301 of the light guide 205, the display light 218 is received by the electrochromic facet 322. Since the electrochromic facet 322 is in the second state (e.g., the transmissive state), the electrochromic facet 322 is configured to transmit the display light 218 toward the reflective facet 324. According to an embodiment, the reflective facet 324 is disposed within the light guide 205 such that the reflective facet 324 has an angle θ2 335 relative to the surface 301 of the light guide 205. In response to receiving the display light 218 from the electrochromic facet 322, the reflective facet 324 is configured to reflect the display light 218 based on the angle θ2 335 of the reflective facet 324. For example, the reflective facet 324 is configured to reflect the display light 218 such that the display light 218 propagates through the light guide 205 along the second path 315. In some embodiments, the second path 315 is associated with a second portion of the FOV area 106 to be illuminated. That is, display light 218 propagating through light guide 205 along second path 315 is configured to illuminate a second portion of FOV area 106 that is different from the first portion of FOV area 106. In this manner, electrochromic reflector 328 is configured to expand FOV area 106 by providing an additional path for display light 218 to propagate through light guide 205. Further, because electrochromic reflector 328 is disposed within light guide 205, electrochromic reflector 328 increases FOV area 106 without increasing the size of an HMD that includes projection system 300.

[0035] In an embodiment, the mirror control circuit system 326 is configured to change the state of one or more electrochromic surfaces 322 of the electrochromic reflector 328 based on the gaze of the user. For example, according to some embodiments, the projection system 300 further includes a gaze tracking circuit system 330. The gaze tracking circuit system 330 includes, for example, a circuit system, a sensor (e.g., an infrared sensor, a laser sensor), a camera, or any combination thereof, configured to determine a gaze direction of the user's eye 220. Based on the determined gaze direction of the user's eye 220, the gaze tracking circuit system 330 is configured to determine which portion of the FOV area 106 the user's eye 220 is looking at. As an example, based on a determined first gaze direction of the user's eye 220, the gaze tracking circuit system 330 is configured to determine that the user's eye 220 is looking at a first portion of the FOV area 106. As another example, based on a determined second gaze direction of the user's eye 220, the gaze tracking circuit system 330 is configured to determine that the user's eye 220 is looking at a second portion of the FOV area 106, which is different from the first portion of the FOV area 106. According to some embodiments, based on determining the portion of the FOV area 106 that the user's eye 220 is looking at, the mirror control circuitry 326 is configured to generate one or more control signals 325.

[0036] As an example, in response to the gaze tracking circuitry 330 determining that the user's eye 220 is looking at a first portion of the FOV area 106, the mirror control circuitry 326 is configured to generate a control signal 325 that, when received by the electrochromic face 322 of the electrochromic reflector 328, causes the electrochromic reflector 328 to direct the display light 218 along a path (e.g., first path 305, second path 315) corresponding to the first portion of the FOV area 106. For example, based on the user's eye 220 looking at the first portion of the FOV area 106, the mirror control circuitry 326 is configured to generate the control signal 325 representing a first current and provide the control signal 325 to the electrochromic face 322. In response to receiving the control signal 325, the electrochromic face 322 is configured to enter a first state (e.g., a reflective state) and is configured to reflect the display light 218 such that the display light propagates through the light guide 205 along the first path 305 corresponding to the first portion of the FOV area 106. As another example, based on the user's eye 220 being looking at a second portion of the FOV area 106 that is different from the first portion, the mirror control circuit system 326 is configured to generate a control signal 325 representing a second current and provide the control signal 325 to the electrochromic face 322. In response to receiving the control signal 325, the electrochromic face 322 is configured to enter a second state (e.g., a transmissive state) and is configured to transmit the display light 218 to the reflective face 324. In response to receiving the display light 218, the reflective face 324 reflects the display light 218 so that the display light propagates through the light guide 205 along a second path 315 corresponding to the second portion of the FOV area 106. In this way, the electrochromic reflector 328 is configured to illuminate only the portion of the FOV area 106 that the user is currently looking at instead of illuminating the entire FOV area 106, thereby reducing the power requirements of the projection system.

[0037] Reference now Figure 4 , presents a projection system 400 including an electrochromic reflector having two or more electrochromic surfaces. According to an embodiment, the projection system 400 is similar or identical to the projection systems 200, 300, and in some embodiments, is used in a HWD or other display system (such as Figure 1In the projection system 400, the electrochromic reflector 328 includes a first electrochromic facet 322 disposed within the light guide 205 at a first angle θ1 345 relative to a surface 301 of the light guide 205, and a second electrochromic facet 432 (e.g., similar or identical to the first electrochromic facet 322) disposed within the light guide 205 at a second angle θ2 405 relative to the surface 201 of the light guide 205. Further, the electrochromic reflector 328 includes a reflective facet 324 disposed within the light guide 205 at a third angle θ3 335 relative to the surfaces 301, 303 of the light guide 205. To control the state of the first electrochromic facet 322, the mirror control circuit system 326 is configured to provide a first set of control signals 325-1, each control signal representing a corresponding voltage, current, or both. Likewise, to control the state of the second electrochromic surface 432, the mirror control circuitry 326 is configured to provide a second set of control signals 325-2, each control signal representing a corresponding voltage, current, or both.

[0038] In an embodiment, the optical engine 202 is configured to emit the display light 218 toward the first surface 301 of the light guide 205. After the display light 218 passes through the first surface 301 of the light guide 205, the display light 218 is received by the second electrochromic facet 405 of the electrochromic reflector 328. In response to the second electrochromic facet 405 being in a first state (e.g., a reflective state), the second electrochromic facet 405 is configured to reflect the display light 218 based on an angle θ2 405 of the second electrochromic facet 405. For example, the second electrochromic facet 405 is configured to reflect the display light 218 such that the display light 218 propagates through the light guide 205 along a first path 415 corresponding to a first portion of the FOV area 106. That is, the display light 218 propagating through the light guide 205 along the first path 415 is configured to illuminate the first portion of the FOV area 106. In response to second electrochromic facet 405 being in the second state (e.g., the transmissive state), second electrochromic facet 405 is configured to transmit display light 218 to first electrochromic facet 322. If first electrochromic facet 322 is in the first state (e.g., the reflective state), first electrochromic facet 322 is configured to reflect display light 218 based on angle θ1 345 of first electrochromic facet 322. As an example, first electrochromic facet 322 is configured to reflect display light 218 such that display light 218 propagates through light guide 205 along a second path 425 corresponding to a second portion of FOV area 106. In an embodiment, display light 218 propagating through light guide 205 along second path 425 is configured to illuminate the second portion of FOV area 106.

[0039] If the first electrochromic face 322 is in the second state (e.g., the transmissive state), the first electrochromic face 322 is configured to transmit the display light 218 to the reflective face 324. In response to receiving the display light 218, the reflective face 324 is configured to reflect the display light 218 based on the angle θ3 335 of the reflective face 324. For example, the reflective face 324 is configured to reflect the display light 218 so that the display light 218 propagates through the light guide 205 along a third path 435 corresponding to a third portion of the FOV area 106. According to an embodiment, the display light 218 propagating through the light guide 205 along the third path 435 is configured to illuminate the third portion of the FOV area 106. In this way, the electrochromic reflector 328 is configured to illuminate certain portions of the FOV area 106 based on the corresponding state of the electrochromic face 322 of the electrochromic reflector 328.

[0040] Reference now Figure 5 , a stacked light guide 500 including an electrochromic reflector is presented. In embodiments, the stacked light guide 500 is implemented in a projection system 200, 300, 400, and in some embodiments, in a HWD or other display system (such as Figure 1 ) is implemented in the display system 100). According to an embodiment, the stacked light guide 500 is formed by a first light guide 205-1 and a second light guide 205-2. The first light guide 205-1, for example, includes a first input coupler 214-1 corresponding to a first portion of the FOV area 106. That is, the first input coupler 214-1 is configured to guide light so that the first portion of the FOV area 106 is illuminated. Further, the second light guide 205-2 includes a second input coupler 214-2, which corresponds to a second portion of the FOV area 106 that is different from the first portion of the FOV area 106. As an example, the second input coupler 214-2 is configured to guide light so that the second portion of the FOV area 106 is illuminated.

[0041] In some embodiments, the first light guide 205-1 includes an electrochromic reflector 328 disposed with the first light guide 205-1. The electrochromic reflector 328 includes, for example, an electrochromic face 322 and a reflective face 324. According to an embodiment, the electrochromic reflector 328 is configured to receive the display light 218 from, for example, the optical engine 202. To this end, within the electrochromic reflector 328, the display light 218 is first received by the electrochromic face 322. In response to the electrochromic face 322 being in a first state (e.g., a reflective state), the electrochromic face 322 is configured to reflect the display light 218, so that the display light 218 propagates through the first light guide 205-1 along the first path 510. In an embodiment, the display light 218 propagating through the first light guide 205-1 along the first path 510 is received by the first input coupler 214-1. After receiving the display light 218, the first input coupler 214-1 guides the display light 218 such that a first portion of the FOV area 106 is illuminated. In response to the electrochromic surface 322 being in the second state (e.g., the transmissive state), the electrochromic surface 322 is configured to transmit the display light 218 to the reflective surface 324. The reflective surface 324 then reflects the display light 218 such that the display light 218 propagates through the first light guide 205-1 along the second path 505. In an embodiment, the display light 218 propagating through the first light guide 205-1 along the second path 505 is received by the second input coupler 214-2 of the second light guide 205-2. After receiving the display light 218, the second input coupler 214-2 guides the display light 218 such that a second portion of the FOV area 106 is illuminated, the second portion being different from the first portion of the FOV area 106.

[0042] Reference now Figure 6 , presents a split EPE 600 including an electrochromic reflector. According to an embodiment, the split EPE 600 is implemented in the projection system 200, 300, 400, and in some embodiments, in a HWD or other display system (such as Figure 1 In an embodiment, the split EPE is configured to expand the exit pupil of the display light 218 and includes a first set of reflective surfaces 324 and a second set of reflective surfaces 634 (e.g., each reflective surface is similar or identical to the reflective surface 324). Figure 6 The example embodiment of the present invention presents the first set of reflective surfaces 324 as including three reflective surfaces (324-1, 324-2, 324-N) representing the number N of reflective surfaces, but in other embodiments, the first set of reflective surfaces 324 may include any number of reflective surfaces. Figure 6The example embodiment of presents the second group of reflective surfaces 634 as including three reflective surfaces (634-1, 634-2, 634-M) representing the number M of reflective surfaces, but in other embodiments, the second group of reflective surfaces 634 may include any number of reflective surfaces. In an embodiment, each reflective surface in the first group of reflective surfaces 324 is configured to reflect a corresponding portion of light (e.g., display light 218) toward a first domain 636-1 of the output coupler 216. The first domain 636-1 of the output coupler 216 is, for example, configured to guide light out of the light guide 205 so that a first portion of the FOV area 106 is illuminated. Further, each reflective surface in the second group of reflective surfaces 634 is configured to reflect a corresponding portion of light (e.g., display light 218) toward a second domain 636-2 of the output coupler 216. The second domain 636 - 2 of the output coupler 216 is, for example, configured to direct light out of the light guide 205 such that a second portion of the FOV area 106 is illuminated, the second portion being different from the first portion of the FOV area 106 .

[0043] In addition, in an embodiment, the split EPE 600 includes an electrochromic reflector (e.g., electrochromic reflector 328) that includes an electrochromic face 322. According to an embodiment, the electrochromic face 322 is configured to receive the display light 218 from the input coupler 214. In response to the electrochromic face 322 being in a first state (e.g., a reflective state), the electrochromic face 322 reflects the display light 218 toward the first set of reflective faces 324. Each reflective face in the first set of reflective faces 324 then reflects a corresponding portion of the display light 218 toward the first domain 636-1 of the output coupler 216. The output coupler 216 then guides the display light 218 out of the light guide 205 so that a first portion of the FOV area 106 is illuminated. In response to the electrochromic face 322 being in a second state (e.g., a transmissive state), the electrochromic face 322 transmits the display light 218 to the second set of reflective faces 634. Each reflective surface in the second set of reflective surfaces 634 then reflects a corresponding portion of the display light 218 toward a second domain 636-2 of the output coupler 216. The output coupler 216 then directs the display light 218 out of the light guide 205 such that a second portion of the FOV area 106 is illuminated, the second portion being different from the first domain of the FOV area 106.

[0044] Reference now Figure 7, presenting an example overlapping portion 706 of a FOV area provided by an electrochromic reflector. For example, a FOV area (e.g., FOV area 106) within an optical combiner 704 of an HWD 702 (e.g., similar or identical to display system 100) is formed by a first portion 706-1 and a second portion 706-2. In an embodiment, the first portion 706-1 and the second portion 706-2 are adjacent in a first (e.g., vertical) direction relative to the optical combiner 704, wherein at least one domain of the first portion 706-1 overlaps with at least one domain of the second portion 706-2. According to an embodiment, the electrochromic reflector (e.g., electrochromic reflector 328) is configured to direct the display light 218 so that the first portion 706-1 or the second portion 706-2 is illuminated based on the state of one or more electrochromic surfaces (e.g., electrochromic surfaces 322, 432). As an example, based on the electrochromic surface being in a first state (e.g., a reflective state), the electrochromic reflector is configured to direct the display light 218 such that the first portion 706-1 is illuminated. Further, based on the electrochromic surface being in a second state (e.g., a transmissive state), the electrochromic reflector is configured to direct the display light 218 such that the second portion 706-2 is illuminated. Now referring to Figure 8 , presenting an example separated portion 806 of the FOV area. In embodiments, the FOV area (e.g., FOV area 106) within the optical combiner 704 of the HWD 702 is formed by a first portion 806-1 and a second portion 806-2. In embodiments, the first portion 806-1 and the second portion 806-2 are adjacent in a second (e.g., horizontal) direction relative to the optical combiner 704, and the entirety of the first portion 806-1 is separated from the entirety of the second portion 806-2, such that the first portion 806-1 and the second portion 806-2 do not overlap. In some embodiments, the electrochromic reflector (e.g., the electrochromic reflector 328) is configured to direct the display light 218 so that the first portion 806-1 or the second portion 806-2 is illuminated based on the state of one or more electrochromic surfaces (e.g., the electrochromic surfaces 322, 432). As an example, based on the electrochromic surface being in a first state (e.g., a reflective state), the electrochromic reflector is configured to direct the display light 218 so that the first portion 806-1 is illuminated. Further, based on the electrochromic surface being in a second state (e.g., a transmissive state), the electrochromic reflector is configured to direct the display light 218 so that the second portion 806-2 is illuminated.

[0045] Fig. 9 A portion of an eyeglass display 900 is shown, the eyeglass display comprising Figure 2 Projection system 200, Figure 3 Projection system 300, Figure 4In some embodiments, the eyewear display 900 represents Figure 1 In this example, the optical engine 202, the input coupler 214, the output coupler 216, and a portion of the light guide 205 are included in a frame 902 of the eyeglass display 900.

[0046] The eyeglass display 900 includes an optical combiner lens 904, which includes a first lens 906, a second lens 908, and a light guide 205, wherein the light guide 205 is disposed between the first lens 906 and the second lens 908. Light exiting through the output coupler 216 travels through the second lens 908 (which corresponds to, for example, the lens element 110 of the display system 100). In use, light exiting the second lens 908 enters the pupil of the eye 220 of the user wearing the eyeglass display 900, thereby causing the user to perceive a display image carried by the display light output by the optical engine 202. The optical combiner lens 904 is substantially transparent, so that light from a real-world scene corresponding to the environment surrounding the eyeglass display 900 passes through the first lens 906, the second lens 908, and the light guide 205 to reach the user's eye 220. In this way, images or other graphical content output by the projection systems 200, 300, 400 are combined (e.g., overlaid) with real-world images of the user's environment when projected onto the user's eyes 220 to provide the user with an AR experience.

[0047] Although not shown in the depicted example, in some embodiments, additional optical elements are included in any of the optical paths between the optical engine 202 and the input coupler 214, between the input coupler 214 and the output coupler 216, and / or between the output coupler 216 and the user's eye 220 (e.g., to shape the display light for viewing by the user's eye 220). As an example, an electrochromic reflector 328 is used to direct the display light 218 within the waveguide 205 so that certain portions of the FOV area 106 are illuminated. Additionally, in some embodiments, an exit pupil expander, such as a folding grating, is disposed in an intermediate stage between the input coupler 214 and the output coupler 216 to receive light coupled into the lightguide 205 by the input coupler 214, expand the light, and redirect the light toward the output coupler 216, where the output coupler 216 then couples the display light out of the waveguide 205 (e.g., toward the user's eye 220).

[0048] In some embodiments, certain aspects of the technology described above can be implemented by one or more processors of a processing system that executes software. The software includes one or more executable instruction sets stored or otherwise tangibly embodied on a non-transitory computer-readable storage medium. The software may include instructions and certain data that manipulate one or more processors to perform one or more aspects of the technology described above when executed by one or more processors. A non-transitory computer-readable storage medium may include, for example, a magnetic or optical disk storage device, a solid-state storage device (such as a flash memory), a cache, a random access memory (RAM), or one or more other non-volatile memory devices, etc. The executable instructions stored on a non-transitory computer-readable storage medium may be in the form of source code, assembly language code, object code, or other instruction formats that are interpreted or otherwise executed by one or more processors.

[0049] Computer-readable storage media may include any storage media or combination of storage media that can be accessed by a computer system during use to provide instructions and / or data to the computer system. Such storage media may include, but are not limited to, optical media (e.g., compact discs (CDs), digital versatile discs (DVDs), Blu-ray discs), magnetic media (e.g., floppy disks, tapes, or magnetic hard disks), volatile memory (e.g., random access memory (RAM) or cache memory), non-volatile memory (e.g., read-only memory (ROM) or flash memory), or micro-electromechanical system (MEMS)-based storage media. Computer-readable storage media may be embedded in a computing system (e.g., system RAM or ROM), securely attached to a computing system (e.g., a magnetic hard drive), removably attached to a computing system (e.g., an optical disc or flash memory based on a universal serial bus (USB)), or coupled to a computer system via a wired or wireless network (e.g., a network accessible storage device (NAS)).

[0050] It should be noted that not all activities or elements described above in the general description are required, a portion of a specific activity or device may not be required, and one or more additional activities may be performed, or, in addition to those described, additional elements may be included. Further, the order in which the activities are listed is not necessarily the order in which they are performed. In addition, the concepts have been described with reference to specific embodiments. However, it should be understood by those of ordinary skill in the art that various modifications and changes may be made without departing from the scope of the present disclosure as set forth in the appended claims. Therefore, the specification and drawings will be regarded as having an illustrative rather than a restrictive meaning, and all such modifications are intended to be included within the scope of the present disclosure.

[0051] Benefits, other advantages, and solutions to problems have been described above with respect to specific embodiments. However, benefits, advantages, solutions to problems, and any features that may make any benefit, advantage, or solution appear or become more significant should not be interpreted as being key, required, or essential features of any or all claims. In addition, the specific embodiments disclosed above are merely illustrative, as the disclosed subject matter may be modified and practiced in different but equivalent ways that are obvious to those skilled in the art who benefit from the teachings herein. Except as described in the appended claims, it is not intended to limit the details of the construction or design shown herein. Therefore, it is apparent that the specific embodiments disclosed above may be changed or modified, and all such variations are considered to be within the scope of the disclosed subject matter. Therefore, the protection sought herein is exactly what is set forth in the appended claims.

Claims

1. A head mounted display (HWD), comprising: an optical engine configured to emit display light; Light guide; as well as An electrochromic facet is configured to direct the display light such that the display light propagates through the light guide along a path of a plurality of paths based on a state of the electrochromic facet. 2 . The HWD of claim 1 , wherein each of the plurality of paths corresponds to a respective portion of a field of view (FOV) area of ​​the HWD. 3 . The HWD of claim 2 , wherein the electrochromic face is configured to guide the display light such that the display light propagates through the light guide along a first path of the plurality of paths based on the electrochromic face being in a first state. 4 . The HWD of claim 3 , wherein the display light propagating through the light guide along the first of the plurality of paths is configured to illuminate a first portion of the FOV area.

5. The HWD of any one of claims 3 or 4, wherein the first state comprises a reflective state and the electrochromic facet is configured to reflect the display light such that the display light propagates through the light guide along the first of the plurality of paths.

6. The HWD of any one of claims 2 to 5, wherein the electrochromic face is configured to guide the display light such that the display light propagates through the light guide along a second path of the plurality of paths based on the electrochromic face being in a second state. 7 . The HWD of claim 6 , wherein the display light propagating through the light guide along the second of the plurality of paths is configured to illuminate a second portion of the FOV area.

8. The HWD according to any one of claims 6 or 7, wherein: The second state comprises a transmissive state; The electrochromic surface is configured to transmit the display light to a reflective surface; and The reflective surface is configured to reflect the display light so that the display light propagates through the light guide along the second path of the plurality of paths.

9. The HWD of claim 8, wherein the electrochromic surface is disposed at a first angle relative to a surface of the light guide, and the reflective surface is disposed at a second angle relative to the surface of the light guide, and wherein the first angle is different from the second angle.

10. The HWD according to any one of claims 1 to 9, further comprising: Mirror control circuitry is configured to control the state of the electrochromic face based on a gaze of a user.

11. The HWD of any one of claims 1 to 10, wherein the electrochromic surface is disposed within the light guide.

12. A light guide for a head mounted display (HWD), comprising: One or more electrochromic facets configured to guide display light such that the display light propagates through the light guide along a path in a plurality of paths based on one or more respective states of the one or more electrochromic facets.

13. The light guide of claim 12, wherein each of the plurality of paths corresponds to a respective portion of a field of view (FOV) area of ​​the HWD.

14. The light guide of claim 13, wherein a first one of the one or more electrochromic facets is configured to guide the display light such that the display light propagates through the light guide along a first one of the plurality of paths based on the first electrochromic facet being in a first state.

15. The light guide of claim 14, wherein the first state comprises a reflective state and the first electrochromic facet is configured to reflect the display light such that the display light propagates along the first path through the light guide.

16. A light guide according to any one of claims 14 or 15, wherein the first electrochromic facet is configured to transmit the display light to a second electrochromic facet of the one or more electrochromic faces based on the first electrochromic facet being in a second state.

17. The light guide of claim 16, wherein the second electrochromic facet is configured to guide the display light such that the display light propagates through the light guide along a second path of the plurality of paths based on the second electrochromic facet being in the first state.

18. The light guide of any one of claims 16 or 17, wherein the second electrochromic facet is configured to guide the display light such that the display light propagates through the light guide along a third path of the plurality of paths based on the second electrochromic facet being in the second state.

19. A light guide according to any one of claims 12 to 18, wherein the one or more corresponding states of the one or more electrochromic surfaces are determined by a mirror control circuit system, and the mirror control circuit system is configured to control the one or more corresponding states of the one or more electrochromic surfaces based on a user's gaze.

20. A light guide according to any one of claims 12 to 19, wherein the one or more electrochromic facets are provided within the light guide.

21. A method comprising: emitting display light toward the light guide; as well as The display light is guided by an electrochromic surface disposed within the light guide such that the display light propagates through the light guide along a path among a plurality of paths based on a state of the electrochromic surface.

22. The method of claim 21, wherein each of the plurality of paths corresponds to a respective portion of a field of view (FOV) area.

23. The method according to claim 22, further comprising: The display light is guided by the electrochromic face such that the display light propagates through the light guide along a first path of the plurality of paths based on the electrochromic face being in a first state.

24. The method of claim 23, wherein the display light propagating through the light guide along the first of the plurality of paths is configured to illuminate a first portion of the FOV area.

25. The method according to any one of claims 23 or 24, further comprising: The display light is guided by the electrochromic face such that the display light propagates through the light guide along a second path of the plurality of paths based on the electrochromic face being in a second state.

26. The method of claim 25, wherein the display light propagating through the light guide along the second of the plurality of paths is configured to illuminate a second portion of the FOV area.

27. The method according to any one of claims 21 to 26, further comprising: The state of the electrochromic surface is controlled based on a gaze of a user.

Images