Magnification lens stack for head-wearable displays

Abstract

A head-wearable display (HWD) configured to present an image to a user includes a first micro-display emitting light representing a first portion of the image and a second micro-display emitting light representing a second portion of the image. Additionally, the HWD includes a first prism that directs the light from the first micro-display to a plano lens stack and a second micro-display that directs the light from the second micro-display to the plano lens stack. This plano lens stack includes a plano concave lens and a plano convex lens that together form a flat surface of an optical combiner of the HWD. Additionally, this plano lens stack is configured to direct the light from the first and second micro-displays such that a magnified version of the image is presented to the user.

Description

MAGNIFICATION LENS STACK FOR HEAD- WEARABLE DISPLAYSBACKGROUND

[0001] Near-eye displays and other head-wearable displays (HWD) are configured to direct light representative of an image to the eye of a user such that the image is viewable within a real-world environment viewable through the HWD. To this end, certain HWDs include waveguides that have diffractive or reflective structures configured to guide light from a projector to the eye of a user. For example, these diffractive or reflective structures first direct light received from a projector into the main body of a waveguide such that the light propagates through the main body of the waveguide via total internal reflection (TIR). The light then propagates through the waveguide until it is received by another diffractive or reflective structure that directs the light out of the waveguide and toward the eye of the user such that images are presented to the user in a field of view (FOV) area of the HWD. This FOV area provided by the HWD is dependent on the type of reflective or diffractive structures used in the waveguide, with different types of reflective and diffractive structures each allowing for different sizes of FOV areas.BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The present disclosure may be better understood, and its numerous features and advantages are made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference symbols in different drawings indicates similar or identical items.

[0003] FIG. 1 is a diagram of an example display system including a piano lens stack configured to magnify and present images to the eye of a user, in accordance with some embodiments.

[0004] FIG. 2 is a diagram of an example optical path for a display architecture including a piano lens stack configured to magnify and present images to the eye of a user, in accordance with some embodiments.

[0005] FIG. 3 is a diagram of an example display architecture including a piano lens stack configured to magnify and present images to the eye of a user, in accordance with some embodiments.

[0006] FIG. 4 is a diagram of an exploded view of an optical combiner including a piano lens stack configured to magnify and present images to the eye of a user, in accordance with some embodiments.SUMMARY OF EMBODIMENTS

[0007] Techniques and systems described herein are directed to reducing the size of a near-eye display or other HWD by implementing a design architecture that includes one or more optical combiners with a piano lens stack. According to an example embodiment, an HWD includes a first micro-display configured to emit a first display light representing at least a first portion of an image and a second micro-display configured to emit a second display light representing at least a second portion of the image. Further, the HWD includes a piano lens stack configured to apply a magnification to the first display light and the second display light and direct the first display light and the second display light so as to form an exit pupil representing the image.

[0008] In embodiments, the HWD can also include a first linear polarizer disposed between the first prism and the first micro-display and a second linear polarizer disposed between the second prism and the second micro-display. Additionally, the HWD can include a first quarter waveplate disposed between the piano lens stack and the first and second prisms and a second quarter waveplate disposed between the piano lens stack and polarizing beam splitter. According to embodiments, the first micro-display may be disposed adjacent to a first side of an optical combiner including the piano lens stack and the second micro-display may be disposed at a second, opposing side of the optical combiner. Further, the piano lens stack can include a piano concave lens and a piano convex lens. As well, the piano concave lens and the plan convex lens may together form at least a portion of a flat surface of an optical combiner of the HWD. In embodiments, the HWD can also include a see- through prism forming at least a portion of a second flat surface of the optical combiner.

[0009] According to another example embodiment, an optical combiner of an HWD includes a first prism arranged to receive a first display light representing at least a first portion of an image and a second prism arranged to receive a second display light representing at least a second portion of the image. Additionally, the HWD includes a piano lens stack that applies a magnification to the first display light and the second display light and directs the first display light and the second display light so as to form an exit pupil representing the image.

[0010] In embodiments, the optical combiner further includes a first linear polarizer disposed between the first prism and a first micro-display configured to emit the first display light and a second linear polarizer disposed between the second prism and a second micro-display configured to emit the second display light. The first linear polarizer and the second linear polarizer are can each configured to polarize light in a first linear direction. Additionally, the optical combiner includes a first quarter waveplate disposed between the piano lens stack and the first and second prisms and a second quarter waveplate disposed between the piano lens stack and polarizing beam splitter. As well, the optical combiner includes a see-through prism forming at least a portion of a flat surface of the optical combiner. Further, the optical combiner can include a third linear polarizer disposed on a surface of the see-through prism. This third linear polarizer can be configured to polarize light in a second linear direction orthogonal to the first linear direction.

[0011] According to embodiments, the optical combiner also includes a see-through prism forming at least a portion of a flat surface of the optical combiner. Additionally, the optical combiner includes a third linear polarizer disposed on a surface of the see-through prism. This third linear polarizer can be configured to polarize light in a second linear direction orthogonal to the first linear direction. Further, the first prism may be disposed adjacent to a first side of the optical combiner and the second prism may be disposed at a second, opposing side of the optical combiner. In embodiments, the piano lens stack can include a piano concave lens and a piano convex lens. As well, the piano concave lens and the piano convex lens may together form at least a portion of a flat surface of the optical combiner.

[0012] In another example embodiment, an HWD includes a first micro-display configured to emit a first display light and a second micro-display configured to emit a second display light. Further, the HWD includes an optical combiner that has a see-through prism configured to receive real-world light and a piano lens. The piano lens stack is arranged to receive the first display light, second display light, and the real- world light and apply a magnification to the first display light and the second display light.

[0013] In embodiments, the HWD wherein the see-through prism may form at least a portion of a first flat surface of the optical combiner and the piano lens stack may form at least a portion of a second flat surface of the optical combiner. Additionally, the optical combiner of the HWD can include a first prism configured to direct the first display light from the first micro-display to the piano lens stack and a second prism configured to direct the second display light from the second micro-display to the piano lens stack. Further, the HWD can include a first linear polarizer disposed between the first prism and the first micro-display and a second linear polarizer disposed between the second prism and the second micro-display. The HWD may also include a third linear polarizer disposed on a surface of the see-through prism. The first linear polarizer and the second linear polarizer can each be configured to polarize light in a first linear direction and the third linear polarizer can be configured to polarize light in a second linear direction orthogonal to the first linear direction.DETAILED DESCRIPTION

[0014] Systems and techniques disclosed herein include HWDs configured to present an image to a user such that the image is visible in a real-world environment visible through the HWD. Such HWDs, for example, are designed to look like eyeglasses and include one or more micro-displays configured to display emit light representative of at least a portion of an image that is then directed to the eye of the user. To this end, the HWDs include a frame designed to be worn in front of a user’s eyes that includes one or more optical combiners configured to direct the light from the microdisplays to the eye of the user such that user is enabled to view both the real-world environment and the images emitted by the micro-displays in an FOV area of the optical combiner. Generally, it is desirable for such optical combiners to have a wide FOV area to accommodate the presenting light across a wide range of angles to the user. Herein, the range of different user eye positions that will be able to see the display is referred to as the eyebox of the optical combiner. Further, components necessary to this functioning of an HWD, such as, for example, the micro-displays, controllers for the micro-displays, cameras to pinpoint physical location, cameras totrack the gaze of the user’s eye(s), processors to power the optical engine, and a power supply, are typically housed within the frame of the HWD. As the frame of an HWD has limited volume in which to accommodate these components, it is desirable that these components be as small as possible and configured to interact with the other components in very small volumes of space. However, fitting components in the HWD frame while still allowing for a relatively large FOV, a relatively large eyebox, a relatively high optical efficiency, a desired display image quality, lower costs, ease of manufacture, or any combination thereof presents certain challenges.

[0015] For example, to direct display light to the eye of a user, the optical combiners of some HWDs implement a diffractive waveguide configured to direct display light to a user. Such HWDs implementing a diffractive waveguide, for example, are configurable to achieve a FOV up to, as an example, 70 degrees, a moderately sized eyebox, and a desired image quality after display calibration. However, the optical efficiency of such HWDs implementing diffractive waveguides can be relatively low (e.g., <1 % ) and the diffractive waveguide are made out of high-cost glass wafers, which are not cost effective. As another example, to direct display light to the eye of a user, the optical combiners of some HWDs implement a reflective waveguide configured to direct display light to a user. These HWDs implementing reflective waveguides, for example, are configurable to achieve a FOV up to, as an example, 50 degrees, a large eyebox, and a desired image quality. However, the optical efficiency of these HWDs implementing reflective waveguides is also low (e.g., <5%) and these HWDs require a complex manufacturing process, resulting in undesirable costs. As yet another example, certain HWDs implement freeform prisms within their optical combiners to direct light to the eye of a user. These freeform prisms, for example, allow for a relatively high optical efficiency (e.g., >50%) within the optical combiners of an HWD but limit the size of a resulting eyebox and increase the likelihood that the quality of a presented image is diminished. As well, such freeform prisms present difficulties for molding and testing, resulting in increased manufacturing costs.

[0016] As such, systems and techniques disclosed herein are directed to increasing the FOV area of an HWD by implementing a display architecture that includes one or more optical combiners that include a piano lens stack. For example, an HWD implementing such a display architecture is designed to look like eyeglasses andincludes a first micro-display configured to emit display light representative of at least a first portion of an image. Further, the HWD includes a second micro-display disposed opposite the first micro-display and configured to emit display light representative of at least a second portion of the image. To direct this display light from the first and second micro-displays to the eye of a user, the display architecture includes one or more eyeglass lenses that include one or more prisms and a piano lens stack. The combination of the eyeglass lens, prisms, and piano lens stack is also referred to hereafter as an “optical combiner,” “optical combiner lens,” or both. For example, the optical combiner includes a first prism (e.g., flat prism) configured to direct the display light emitted from the first micro-display to the piano lens stack via total internal reflection (TIR), partial internal reflection (FIR), or both. Likewise, the optical combiner includes a second prism (e.g., flat prism) configured to direct the display light emitted from the second micro-display to the piano lens stack via TIR, PIR, or both. The piano lens stack of the optical combiner, for example, includes a piano concave and a piano convex lens that together form a shape having opposing flat surfaces. Based on receiving the display light from a prism, the piano lens stack relays the display light to the eye of the user such that a predetermined magnification is applied to the portion of the image represented by the display light. Further, the piano lens stack is configured to concurrently direct the display lights received from the first and second prims such that an exit pupil representing the image (e.g., as magnified by the piano lens stack) of the display lights forms near the eye of the user. Such an exit pupil, for example, refers to the location along the optical path where beams of the display lights from both the first and second micro-displays intersect to form the image. In this way, the optical combiner is configured to direct the display lights from the first and second micro-displays such that the user is able view a magnified version of the image represented by the display lights.

[0017] By implementing such a display architecture, the HWD is configurable to achieve a FOV up to, for example, 120 degrees without degrading the quality of the image represented by the display lights emitted by the micro-displays. Additionally, the HWD is configurable to achieve a display optical efficiency of up to 25% while also maintaining a relatively large eyebox. Further, due to the display architecture implementing flat prisms and a piano lens stack having flat surfaces, the thickness of the HWD, complexity of manufacturing the HWD, and complexity of testing the HWD is reduced when compared to HWDs that implement other displayarchitectures such as diffractive waveguides, reflective waveguides, freeform prisms, and the like.

[0018] FIG. 1 illustrates an example display system 100 having a support structure 102 that includes an arm 104, which houses a display system configured to direct display light representative of images toward the eye of a user, such that the user perceives the projected images as being displayed in a field of view (FOV) area 106 of a display at one or both of lens elements 108, 110. In the depicted embodiment, the display system 100 is a head-worn display (HWD) that includes a support structure 102 configured to be worn on the head of a user and has a general shape and appearance of an eyeglasses (e.g., sunglasses) frame. The support structure 102 contains or otherwise includes various components to facilitate the presentation of such images toward the eye of the user, such as one or more emitters (e.g., microdisplays), prisms, lens stacks, or any combination thereof. As an example, the support structure 102 contains or otherwise includes two micro-displays, two prisms, and a piano lens stack together configured to present an image to the eyes of a user. 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 further can include one or more radio frequency (RF) interfaces or other wireless interfaces, such as a Bluetooth interface, a Wi-Fi interface, and the like. Further, in some embodiments, the support structure 102 includes one or more batteries or other portable power sources for supplying power to the electrical components of the display system 100. Some or all of these components of the display system 100, according to embodiments, are fully or partially contained within an inner volume of support structure 102, such as within a bridge of the support structure 102, the arm 104 of the support structure 102, or the like. It should be noted that while an example form factor is depicted, it will be appreciated that in other embodiments the display system 100 may have a different shape and appearance from the eyeglasses frame depicted in FIG. 1.

[0019] One or both of the lens elements 108, 110 are used by the display system 100 to provide an augmented reality (AR) display in which rendered graphical content can be superimposed over or otherwise provided in conjunction with a real-world view as perceived by the user through the lens elements 108, 110. For example, display lightused to form a perceptible image or series of images may be emitted by one or more micro-displays the display system 100 and guided toward the eye of the user via a series of optical elements, such as one or more prisms, plano-convex lenses, planoconcave lenses, or any combination thereof formed at least partially in the corresponding lens element 108, 110. As an example, one or both of the lens elements 108, 110 include one or more optical combiners that have prisms configured to route display light emitted by a micro-display to a piano lens stack using TIR, PIR, or both. Such a piano lens stack, for example, includes a plano-concave lens and a plano-convex lens together configured to direct received display light toward the eye of the user such that the image represented by the display light is magnified (e.g., the size of the image is increased) when compared to the image represented by the display light emitted by the micro-display. In addition, in embodiments, each of the lens elements 108, 110 is sufficiently transparent to allow a user to see through the lens elements to provide an FOV of the user’s real-world environment such that the image appears superimposed over at least a portion of the real-world environment.

[0020] In some embodiments, each micro-display of the display system 100 includes a light emitting diode (LED) micro-display, organic light emitting diode (OLED) microdisplay, advanced matrix organic light emitting diode (AMOLED), or the like configured to emit light representative of at least a portion of an image. As an example, according to some embodiments, display system 100 includes a first microdisplay configured to emit display light representative of a first portion of an image and a second micro-display configured to emit light representative of a second portion of the image. A first prism of an optical combiner of display system 100 then guides the display light representative of the first portion to a piano lens stack and a second prism of the optical combiner guides the display light representative of the second potion to the piano lens stack. Based on receiving the display lights representative of the first and second portions of the image, the piano lens stack directs the display lights such that a magnified version of the image is presented to the eye of a user over a variable area, designated the FOV area 106, of the display system 100. Generally, it is desirable for a display to have a wide FOV to accommodate the presentation of an image to a user across a wide range of angles. In some embodiments, each micro-display is communicatively coupled to a controller and a non-transitory processor-readable storage medium or a memory that storesprocessor-executable instructions and other data that, when executed by the controller, cause the controller to control the operation of the micro-display. A controller, according to some embodiments, is communicatively coupled to a processor (not shown) that generates content to be displayed at the display system 100.

[0021] Referring now to FIG. 2, an example optical path 200 for a display architecture including a piano lens stack is presented, in accordance with some embodiments. In embodiments, example optical path 200 is implemented in display system 100 and is configured to present an image to the eye 232 of a user. For example, in some embodiments, example optical path 200 is implemented in an optical combiner (e.g., lens element 108, 110) of display system 100. Example optical path 200 has, for example, a first micro-display 212 that includes an LED micro-display, OLED microdisplay, AMOLED micro-display, or the like configured to emit a first display light 214 representative of at least a first portion of an image 228. According to embodiments, the first micro-display 212 is disposed adjacent to or near a first side of an optical combiner. For example, in some embodiments, the first micro-display 212 is disposed adjacent to or near a first side (e.g., top) of an optical combiner such that the display light 214 emitted by the first micro-display 212 is received by a first prism 216 disposed at the first side of the optical combiner. The first prism 216 includes, for example, a flat prism having two flat, opposing sides and configured to direct display light 214 received from the first micro-display 212 to a piano lens stack 226 via TIR, PIR, or both. As an example, within the first prism 216, display light 214 is configured to reflect off the surfaces of the first prism 216 such that the display light 214 propagates through body of the first prism 216 via TIR, PIR, or both. Further, example optical path 200 includes a second micro-display 218 (e.g., LED microdisplay, OLED micro-display, or AMOLED micro-display) configured to emit a second display light 220 representative of at least a second portion of an image 228. In some embodiments, the first portion of the image 228 represented by the first display light 214 differs from the second portion of the image 228 represented by the second display light 220. The second micro-display 218, in embodiments, is disposed adjacent to or near a second side of an optical combiner. As an example, the second micro-display 218 is disposed adjacent to or near a second side (e.g., bottom) of an optical combiner such that the display light 220 emitted by the second micro-display 218 is received by a second prism 222 disposed at the second side of the opticalcombiner. Such a second prism 222 includes, for example, a flat prism having two flat, opposing sides and configured to direct display light 220 received from the second micro-display 218 to the piano lens stack 226 via TIR, PIR, or both.

[0022] Plano lens stack 226, for example, includes one or more piano concave lenses, piano convex lenses, linear polarizers, quarter waveplates, polarizing beam splitters, or any combination thereof. As an example, the piano lens stack 226 includes a piano concave lens having a flat side disposed adjacent to a first side (e.g., real-world side) of the optical combiner and a concave surface opposite the flat side. Further, the piano lens stack 226 includes a piano convex lens having a convex surface disposed adjacent to the concave surface of the piano concave lens and a flat surface opposite the convex surface. In embodiments, piano lens stack 226 is configured to relay display light 214 from the first prism 216 and display light 220 from the second prism 222 toward the eye 232 of a user such that both display light 214 and display light 220 converge to form an exit pupil representing image 228. That is, piano lens stack 226 is configured to relay display light 214 representing at least a first portion of image 228 and display light 220 representing at least a second portion of image 228 such that an exit pupil representing image 228 is formed near the eye 232 of the user. Additionally, according to embodiments, piano lens stack 226 is configured to apply a magnification 230 to the first portion of the image 228 represented by display light 214 and the second portion of the image 228 represented by display light 220 such that the resulting exit pupil presents a magnified image 228 when compared to the image 228 emitted by the first microdisplay 212, the second micro-display 218, or both. In this way, example optical path 200 is configured to magnify and present the image 228 emitted by the first microdisplay 212, the second micro-display 218, or both to the eye 232 of the user.

[0023] According to embodiments, the first micro-display 212, the second microdisplay 218, or both are configured to emit display lights 214 and 220, respectively, based on signals from controller 224. Controller 224, for example, includes one or more processors, micro-processors, programable logic devices (e.g., field- programmable gate array (FPGA), microcontrollers, or the like configured to generate signals that cause the first micro-display 212, the second micro-display 218, or both to emit light representing at least a portion of an image. Though the example embodiment presented in FIG. 2 shows a single controller 224 controlled both thefirst micro-display 212 and the second micro-display 218, in other embodiments, distinct controllers 224 may control the first micro-display 212 and the second microdisplay 218, respectively. Further, in some embodiments, one or more additional components may be arranged between various elements of example optical path 200 (e.g., first micro-display 212, second micro-display 218, the first prism 216, the second prism 222, the piano lens stack 226) such as one or more linear polarizers, quarter waveplates, polarizing beam splitters, lenses, or any combination thereof.

[0024] Referring now to FIG. 3, an example display architecture 300 including a piano lens stack is presented, in accordance with some embodiments. In embodiments, example display architecture 300 is included within an optical combiner (e.g., lens element 108, 110) of display system 100 and implements at least a portion of example optical path 200. According to some embodiments, example display architecture 300 is arranged such that example display architecture 300 includes a user side 348 facing the eye 232 of a user and a real-world side 350 facing a real- world environment viewable through the components of example display architecture 300. Within example display architecture 300, the first micro-display 212 emits display light 214 representing at least a first portion of an image 228 and the second micro-display 218 emits display light 220 representing at least a second portion of image 228. According to embodiments, the first micro-display 212 is disposed adjacent to or near a first side (e.g., top side) of example display architecture 300 (e.g., adjacent to or near a first side of the optical combiner implementing example display architecture 300) and the second micro-display 218 is disposed opposite the first micro-display 212 such that the second micro-display 218 is disposed adjacent to or near a second side (e.g., bottom side) of example display architecture 300 (e.g., adjacent to or near a second side of the optical combiner implementing example display architecture 300). In embodiments, example display architecture 300 includes a first lens 334 configured to direct display light 214 from the first micro-display 212 to induce TIR, PIR, or both of display light 214 within the first prism 216. For example, the first lens 334 is configured to direct display light 214 such that display light 214 passes through a first surface (e.g., flat surface) 336 of the first prism 216 and propagates through the first prism 216 via TIR, PIR, or both. Such a first lens 334, for example, includes a lens formed from plastic, glass, or the like. Further, example display architecture 300 includes a second lens 344 formed from plastic, glass, or the like and configured to direct display light 220 from the second micro-display 218 toinduce TIR, PIR, or both of display light 220 within the second prism 222. As an example, the second lens 344 is configured to direct display light 220 such that display light 220 passes through a first surface (e.g., flat surface) 346 of the second prism 222 and propagates through the second prism 22 via TIR, PIR, or both.

[0025] According to embodiments, the first and second prisms 216 are configured to direct display light 214 and display light 220, respectively, to a piano lens stack (e.g., piano lens stack 226) including a piano concave lens 338 and a piano convex lens 340 each formed, for example, from glass, plastic, or the like. Within example display architecture 300, the piano concave lens 338 is arranged such that display light 214 and display light 220 first pass through the flat surface of piano concave lens 338 and then through the opposing concave surface of the piano concave lens 338. Further, piano concave lens 338 is arranged such that display light 214 and display light 220 are collimated after they pass through the concave surface of the piano concave lens 338. Additionally, the piano convex lens 340 is arranged such that after passing through the concave surface of the piano concave lens 338, display light 214 and display light 220 pass through the convex surface of the piano convex lens 340 and then the flat surface of the piano convex lens 340. The piano convex lens 340 is arranged within the piano lens stack so as to apply a magnification 230 to both the display light 214 and display light 220. Further, the piano convex lens 340 is arranged such that display light 214 and display light 220 form an exit pupil 305 representing a magnified image 228 near the eye 232 of a user. According to some embodiments, piano concave lens 338 and piano convex lens 340 are disposed such that they together form a shape having two opposing, flat surfaces. For example, the convex surface of the piano convex lens 340 is configured to mate with the concave of the piano concave lens 338 such that the piano convex lens 340 and piano concave lens 338 together form a shape having a two opposing, flat surface. In some embodiments, a flat surface of the shape formed from the piano convex lens 340 and piano concave lens 338 form a flat surface of an optical combiner of display system 100.

[0026] Additionally, example display architecture 300 includes a see-through prism 342 disposed at the real-world side 350 of example display architecture 300. This see-through prism 342, for example, is formed from plastics, glass, or the like and is configured to let pass through without modification. As an example, see-throughprism 342 allows light from a real-world environment to be transmitted to the eye 232 of the user such that the user is able to view the real-world environment. Further, see-through prism 342 includes a flat surface 315 disposed at real-world side 350 of example display architecture 300 that forms at least a portion of a flat surface of an optical combiner of display system 100. For example, flat surface 315 forms at least a portion of a flat surface of an optical combiner of display system 100 opposite the flat surface formed by the piano convex lens 340 and piano concave lens 338. Further, as discussed below with reference to FIG. 4, example display architecture 300 includes one or more components (e.g., linear polarizers, quarter wave plates, polarizing beam splitters) disposed between two or more elements of the example display architecture 300. For example, in some embodiments, example display architecture 300 includes a quarter wave plate disposed adjacent to the flat surface of the piano convex lens 340 and a polarizing beam splitter disposed adjacent to the quarter wave plate. As display light 214 and display light 220 exit the piano convex lens 340, the quarter wave plate circularly polarizes display light 214 and display light 220 such that the display light 214 and display light 220 are linearly polarized in a first direction. The quarter waveplate then provides the linearly polarized display light 214 and display light 220 to the polarizing beam splitter which reflects the linearly polarized display light 214 and display light 220 back to the piano convex lens 340 through the quarter waveplate. As the linearly polarized display light 214 and display light 220 pass through the quarter waveplate, the linearly polarized display light 214 and display light 220 become circularly polarized in a second direction. This circularly polarized display light 214 and display light 220 then reflect off the convex surface of the piano convex lens 340 toward the quarter waveplate which again circularly polarized the circularly polarized display light 214 and display light 220 such that the display light 214 and display light 220 are linearly polarized in a second direction orthogonal to the first direction. This linearly polarized display light 214 and display light 220 is then transmitted by the polarizing beam splitter and forms exit pupil 305. By reflecting display light 214 and display light 220 off the convex surface of the piano convex lens 340 in this way, a predetermined magnification 230 associated with the piano convex lens 340 is applied to display light 214 and display light 220.

[0027] Referring now to FIG. 4, an exploded view of an example optical combiner 400 including a piano lens stack is presented, in accordance with embodiments.According to some embodiments, example optical combiner 400 is implementedwithin example display architecture 300, display system 100, or both. Example optical combiner 400 includes, for example, a first linear polarizer 458 disposed adjacent to a surface (e g. , flat surface 336) of the first prism 216. The first linear polarizer 458, for example, includes a polarizing film (e.g., polymer film, polyvinyl alcohol film) and is configured to polarize light in a first linear direction. For example, as display light 214 is emitted from the first micro-display 212, display light 214 passes through the first linear polarizer 458 and becomes polarized in the first linear direction before being received by the first prism 216. Further, example optical combiner 400 includes a second linear polarizer 460 disposed adjacent to a surface (e.g., flat surface 346) of the second prism 222. The second linear polarizer 460, for example, includes a polarizing film (e.g., polymer film, polyvinyl alcohol film) and is configured to polarize light in the first linear direction. As display light 220 is emitted from the second microdisplay 218, display light 220 passes through the second linear polarizer 460 and becomes polarized in the first linear direction before being received by the second prism 222.

[0028] Further, in embodiments, example optical combiner 400 includes a first quarter waveplate 462 disposed between the piano concave lens 338 and the first and second prisms 216, 222. This first quarter waveplate 462, for example, includes a quarter waveplate film (e.g., polymer film, polyvinyl alcohol film) and is configured to polarize linearly polarized light in a first circular direction. As an example, within example optical combiner 400, display light 214 and display light 220 pass through the first quarter waveplate 462 after exiting the first prism 216 or second prism 222, respectively, and before being received by the piano concave lens 338. As display light 214 and display light 220, each linearly polarized in the first direction, pass through the first quarter waveplate 462, display light 214 and display light 220 both become polarized in a first circular direction. Additionally, example optical combiner 400 includes a second quarter waveplate 464 arranged so as to receive display light 214 and display light 220 after they exit the piano convex lens 340. The second quarter waveplate 464, for example, includes a quarter waveplate film (e.g., polymer film, polyvinyl alcohol film) and is configured to polarize linearly polarized light in the first circular direction. For example, as display light 214 and display light 220, both polarized in the first circular direction, pass through the second quarter waveplate 464 after exiting the piano convex lens 340, display light 214 and display light 220 are again circularly polarized such that display light 214 and display light 220 arepolarized in second linear direction orthogonal to the first linear direction (e.g., orthogonal to the linear direction of the first linear polarizer 458 and the second linear polarizer 460.) Additionally, example optical combiner 400 includes a polarizing beam splitter 466 configured to receive display light 214 and display light 220 after they exit the second quarter waveplate 464. The polarizing beam splitter 466 includes a cube polarizing beam splitter, plate polarizing beam splitter, or the like and is configured to split an incident beam (e.g., beam of light) into a first portion of the beam polarized in a first linear direction and a second portion of the beam polarized in a second linear direction. In embodiments, based on receiving display light 214 and display light 220 polarized in the second linear direction, polarizing beam splitter 466 is configured to reflect display light 214 and display light 220 back toward the piano convex lens 340 via the second quarter waveplate 464.

[0029] As display light 214 and display light 220, both linearly polarized in the second linear direction, again pass through the second quarter waveplate 464, the second quarter waveplate 464 circularly polarizes display light 214 and display light 220 such that display light 214 and display light 220 are polarized in a second circular direction. After passing through the second quarter waveplate 464, display light 214 and display light 220 are provided to the piano convex lens 340 and reflect off the convex surface of the piano convex lens 340 such that a magnification 230 is applied to display light 214 and display light 220 and display light 214 and display light 220 are directed back toward the polarizing beam splitter 466 via the second quarter waveplate 464. As display light 214 and display light 220, both polarized in the second circular direction, pass through the second quarter waveplate 464, the second quarter waveplate 464 circularly polarizes display light 214 and display light 220 such that display light 214 and display light 220 are polarized in the first linear direction. Based on receiving display light 214 and display light 220 polarized in the first linear direction, polarizing beam splitter 466 transmits display light 214 and display light 220 toward a third linear polarizer 468 disposed between the polarizing beam splitter 466 and an eye 232 of the user. This third linear polarizer 468, for example, includes a linear polarizing film and is configured to polarize light in the first linear direction.

[0030] Additionally, example optical combiner 400 includes a fourth linear polarizer452 disposed on a surface (e.g., flat surface 315) of see-through prism 342. Thefourth linear polarizer 452 includes, for example, a linear polarizing film (e.g., polymer film, polyvinyl alcohol film) and is configured to polarize light in the second linear direction (e.g., in a direction orthogonal to the first and second linear polarizers 458, 460). As light from the real world, also referred to herein as “real-world light’’ passes through the fourth linear polarizer 452, the real-world light is polarized in the second linear direction. The real-world light then passes through the see-through prism 342 and is received by a second polarizing beam splitter 454, a third polarizing beam splitter 456, or both. Both the second polarizing beam splitter 454 and the third polarizing beam splitter 456 include a cube polarizing beam splitter, plate polarizing beam splitter, or the like configured to reflect light polarized in the first linear direction and transmit light polarized in the second linear direction toward the piano concave lens 338 via the first quarter waveplate 462. After the real-world light, polarized in the second linear direction, passes through the second polarizing beam splitter 454, the third polarizing beam splitter 456, or both, the real-world light passes through the first quarter waveplate 462 and is polarized in a first circular direction. The real-world light, polarized in the first circular direction, then passes through the piano concave lens 338 and the piano convex lens 340 and is received by the second quarter waveplate 464. The second quarter waveplate then polarizes the real-world light such that the real-world light is polarized in the first linear direction. The real-world light, polarized in the first linear direction, then passes through the polarizing beam splitter 466 and third linear polarizer 468 and is received at the eye 232 of the user. In this way, due to the fourth linear polarizer 452 polarizing the real-world light in a linear direction orthogonal to the first and second linear polarizers 458, 460, the piano convex lens 340 does not apply the magnification 230 to the real-world light as the real-world light is not reflected back to the piano convex lens 340. As such, example optical combiner 400 is configured to apply the magnification 230 to display light 214 and display light 220 without applying the magnification 230 to the real-world light.

[0031] In some embodiments, certain aspects of the techniques described above may be implemented by one or more processors of a processing system executing software. The software comprises one or more sets of executable instructions stored or otherwise tangibly embodied on a non-transitory computer readable storage medium. The software can include the instructions and certain data that, when executed by the one or more processors, manipulate the one or more processors to perform one or more aspects of the techniques described above. The non-transitorycomputer readable storage medium can include, for example, a magnetic or optical disk storage device, solid state storage devices such as Flash memory, a cache, random access memory (RAM) or other non-volatile memory device or devices, and the like. The executable instructions stored on the non-transitory computer readable storage medium may be in source code, assembly language code, object code, or other instruction format that is interpreted or otherwise executable by one or more processors.

[0032] A computer readable storage medium may include any storage medium, or combination of storage media, accessible by a computer system during use to provide instructions and / or data to the computer system. Such storage media can include, but is not limited to, optical media (e.g., compact disc (CD), digital versatile disc (DVD), Blu-Ray disc), magnetic media (e.g., floppy disc , magnetic tape, or magnetic hard drive), volatile memory (e.g., random access memory (RAM) or cache), non-volatile memory (e.g., read-only memory (ROM) or Flash memory), or microelectromechanical systems (MEMS)-based storage media. The computer readable storage medium may be embedded in the computing system (e.g., system RAM or ROM), fixedly attached to the computing system (e.g., a magnetic hard drive), removably attached to the computing system (e.g., an optical disc or Universal Serial Bus (USB)-based Flash memory), or coupled to the computer system via a wired or wireless network (e.g., network accessible storage (NAS)).

[0033] Note that not all of the activities or elements described above in the general description are required, that a portion of a specific activity or device may not be required, and that one or more further activities may be performed, or elements included, in addition to those described. Still further, the order in which activities are listed are not necessarily the order in which they are performed. Also, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present disclosure as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present disclosure.

[0034] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages,solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims. Moreover, the particular embodiments disclosed above are illustrative only, as the disclosed subject matter may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. No limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope of the disclosed subject matter. Accordingly, the protection sought herein is as set forth in the claims below.

Claims

WHAT IS CLAIMED IS:

1. A head-wearable display, comprising: a first micro-display configured to emit a first display light representing at least a first portion of an image; a second micro-display configured to emit a second display light representing at least a second portion of the image; and a piano lens stack configured to: apply a magnification to the first display light and the second display light; and direct the first display light and the second display light so as to form an exit pupil representing the image.

2. The head-wearable display of claim 1 , further comprising: a first prism configured to direct the first display light from the first microdisplay to the piano lens stack; and a second prism configured to direct the second display light from the second micro-display to the piano lens stack.

3. The head-wearable display of claim 2, further comprising: a first linear polarizer disposed between the first prism and the first microdisplay; and a second linear polarizer disposed between the second prism and the second micro-display.

4. The head-wearable display of claim 3, further comprising: a first quarter waveplate disposed between the piano lens stack and the first and second prisms; and a second quarter waveplate disposed between the piano lens stack and polarizing beam splitter.

5. The head-wearable display of claim 1 , wherein the first micro-display is disposed adjacent to a first side of an optical combiner including the piano lens stack and the second micro-display is disposed at a second, opposing side of the optical combiner.

6. The head-wearable display of claim 1 , wherein the piano lens stack includes a piano concave lens and a piano convex lens.

7. The head-wearable display of claim 6, wherein the piano concave lens and the piano convex lens together form at least a portion of a flat surface of an optical combiner of the head-wearable display.

8. The head-wearable display of claim 7 wherein the head-wearable display further includes: a transparent prism forming at least a portion of a second flat surface of the optical combiner.

9. An optical combiner of a head-wearable display, comprising: a first prism arranged to receive a first display light representing at least a first portion of an image; a second prism arranged to receive a second display light representing at least a second portion of the image; and a piano lens stack configured to: apply a magnification to the first display light and the second display light; and direct the first display light and the second display light so as to form an exit pupil representing the image.

10. The optical combiner of claim 9, further comprising: a first linear polarizer disposed between the first prism and a first micro-display configured to emit the first display light; and a second linear polarizer disposed between the second prism and a second micro-display configured to emit the second display light, wherein the first linear polarizer and the second linear polarizer are each configured to polarize light in a first linear direction.11 . The optical combiner of claim 10, further comprising: a first quarter waveplate disposed between the piano lens stack and the first and second prisms; anda second quarter waveplate disposed between the piano lens stack and polarizing beam splitter.

12. The optical combiner of claim 10, further comprising: a transparent prism forming at least a portion of a flat surface of the optical combiner.

13. The optical combiner of claim 12, further comprising: a third linear polarizer disposed on a surface of the transparent prism, wherein the third linear polarizer is configured to polarize light in a second linear direction orthogonal to the first linear direction.

14. The optical combiner of claim 9, wherein the first prism is disposed adjacent to a first side of the optical combiner and the second prism is disposed at a second, opposing side of the optical combiner.

15. The optical combiner of claim 9, wherein the piano lens stack includes a piano concave lens and a piano convex lens.

16. The optical combiner of claim 15, wherein the piano concave lens and the piano convex lens together form at least a portion of a flat surface of the optical combiner.

17. A head-wearable display, comprising: a first micro-display configured to emit a first display light; a second micro-display configured to emit a second display light; and an optical combiner, the optical combiner including: a transparent prism configured to receive real-world light; and a piano lens stack arranged to: receive the first display light, second display light, and the real- world light; and apply a magnification to the first display light and the second display light.

18. The head-wearable display of claim 17, wherein the transparent prism forms at least a portion of a first flat surface of the optical combiner and the piano lens stack forms at least a portion of a second flat surface of the optical combiner.

19. The head-wearable display of claim 17, wherein the optical combiner further includes: a first prism configured to direct the first display light from the first microdisplay to the piano lens stack; and a second prism configured to direct the second display light from the second micro-display to the piano lens stack.

20. The head-wearable display of claim 19, further comprising: a first linear polarizer disposed between the first prism and the first microdisplay; a second linear polarizer disposed between the second prism and the second micro-display; and a third linear polarizer disposed on a surface of the transparent prism. wherein the first linear polarizer and the second linear polarizer are each configured to polarize light in a first linear direction and the third linear polarizer is configured to polarize light in a second linear direction orthogonal to the first linear direction.

Images