The present disclosure relates generally to electronic displays, and more specifically to a smart glasses device having microLED projector arrays.
Head-Mounted Displays (HMD's) and virtual image near-eye displays are being developed for a range of diverse uses, including military, commercial, industrial, fire-fighting, and entertainment applications. For many of these applications, there is value in forming a virtual image that can be visually superimposed over the real-world image that lies in the field of view of the HMD user. An optical image light guide may convey image-bearing light to a viewer in a narrow space for directing the virtual image to the viewer's pupil and enabling this superposition function.
With rapid advances in technology, manufacturers of mobile devices (e.g., head mounted displays, smart glasses, etc.) are continually challenged to add greater functional capability in smaller form to achieve convenience of mobility. Although conventional image light guide arrangements have provided significant reduction in bulk, weight, and overall cost of near-eye display optics, further improvements are needed. In some instances, the size and brightness of the image source (e.g., projector) constrains the size and placement of other components, forcing HMD designs to limit tolerances for movement and device placement. Thus, there is particular value in an image source having reduced size, yet having the capability to produce the desired virtual image brightness.
The present disclosure provides for a monolithic multi-array LED projector.
In a first exemplary embodiment, the present disclosure provides for an image source including a first light emitting diode array and a second light emitting diode array coupled with a fixed panel. The image source further including a first lens system located at an effective focal length from the first light emitting diode array and a second lens system located at an effective focal length from the second light emitting diode array. Light from corresponding light emitting diodes in the first and second light emitting diode arrays aligned to form a single pixel in an image.
In an embodiment, the image source may further enable digitally aligning pixels generated by said first and second light emitting diode arrays via changing an ON/OFF state of one or more light emitting diodes of one or more of said first and second light emitting diode arrays until said pixels align.
In an embodiment, the image source may further enable aligning pixels generated by said first and second light emitting diode arrays via independently adjusting one or more lenses of the first and second lens systems to align light from the corresponding individual light emitting diodes to form a single pixel in a virtual image.
In an embodiment, the image source may further enable aligning pixels generated by said first and second light emitting diode arrays via independently adjusting one or more of the first and second light emitting diode arrays to align light from the corresponding individual light emitting diodes to form a single pixel in a virtual image.
In a second exemplary embodiment, the present disclosure provides for an image light guide for conveying a virtual image including an image source having a first addressable light emitting diode array operable to emit a first image-bearing light beam in a first direction, a second addressable light emitting diode array configured to emit a second image-bearing light beam in a second direction perpendicular to the first direction, and a third addressable light emitting diode array. The image source further including a beam combiner located in an optical path of the first and second light emitting diode arrays, a first lens system located at an effective focal length from the first light emitting diode array and the second light emitting diode array, wherein image-bearing light from the beam combiner is incident on the first lens system. The image source also including a second lens system located at an effective focal length from the third light emitting diode array. The image light guide including a planar waveguide operable to propagate image-bearing light beams, a first in-coupling diffractive optic formed along the waveguide, wherein the first in-coupling diffractive optic is operable to diffract at least a portion of the image-bearing light beams from the first and second light emitting diode arrays into the waveguide in an angularly encoded form, a second in-coupling diffractive optic formed along the waveguide, wherein the second in-coupling diffractive optic is operable to diffract at least a portion of the image-bearing light beams from the third light emitting diode array into the waveguide in an angularly encoded form, and an out-coupling diffractive optic formed along the waveguide, wherein the out-coupling diffractive optic is operable to expand the image-bearing light beams and direct the expanded image-bearing light beams from the waveguide in an angularly decoded form toward an eyebox. Wherein image-bearing light from corresponding individual light emitting diodes in the first, second, and third light emitting diode arrays are aligned to form a single pixel in a virtual image as viewed in the eyebox.
In a third exemplary embodiment, the present disclosure provides for a method of aligning pixels of different wavelength ranges including providing a fixed panel; providing a first light emitting diode array coupled with the fixed panel; providing a second light emitting diode array coupled with the fixed panel; providing a first lens system located at an effective focal length from the first light emitting diode array; providing a second lens system located at an effective focal length from the second light emitting diode array; providing an alignment lens adjacent to the first and second lens systems, wherein light transmitted through the first and second lens systems is incident upon the alignment lens; providing a display surface at an effective focal length distance from the alignment lens opposite the first and second lens systems; generating a first light beam forming a first pixel with the first light emitting diode array; generating a second light beam forming a second pixel with the second light emitting diode array; and aligning the first and second pixels on the display surface.
The accompanying drawings are incorporated herein as part of the specification. The drawings described herein illustrate embodiments of the presently disclosed subject matter and are illustrative of selected principles and teachings of the present disclosure. However, the drawings do not illustrate all possible implementations of the presently disclosed subject matter and are not intended to limit the scope of the present disclosure in any way.
It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific assemblies and systems illustrated in the attached drawings and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions, or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. Also, although they may not be, like elements in various embodiments described herein may be commonly referred to with like reference numerals within this section of the application.
Where they are used herein, the terms “first”, “second”, and so on, do not necessarily denote any ordinal, sequential, or priority relation, but are simply used to more clearly distinguish one element or set of elements from another, unless specified otherwise.
Where they are used herein, the terms “viewer”, “operator”, “observer”, and “user” are considered to be equivalent and refer to the person or machine wearing and/or viewing images using an electronic device.
Where used herein, the term “set” refers to a non-empty set, as the concept of a collection of elements or members of a set is widely understood in elementary mathematics. The term “subset”, unless otherwise explicitly stated, is used herein to refer to a non-empty proper subset, that is, to a subset of the larger set, having one or more members. For a set S, a subset may comprise the complete set S. A “proper subset” of set S, however, is strictly contained in set S and excludes at least one member of set S.
Where used herein, the terms “beam expansion,” “expansion of an image-bearing beam,” and “expanded image-bearing light” are intended to mean replication of a beam via multiple encounters with an optical element to provide exit pupil expansion in one or more directions. Similarly, as used herein, to “expand” a beam, or a portion of a beam, is intended to mean replication of a beam via multiple encounters with an optical element to provide exit pupil expansion in one or more directions.
Head-Mounted Displays (HMDs) are developed for a range of diverse uses, including military, commercial, industrial, fire-fighting, and entertainment applications. An HMD is operable to form a virtual color image that can be visually superimposed over the real-world image that lies in the field of view of the HMD user. Optically transparent flat parallel plate waveguides, also called planar waveguides, convey image-bearing light generated by a polychromatic, or monochromatic, projector system to the HMD user. The planar waveguides convey the image-bearing light in a narrow space to direct the image to the HMD user's pupil and enable the superposition of the virtual image over the real-world image that lies in the field of view of the HMD user.
In imaging light guides, collimated, relatively angularly encoded light beams from a color image projector source are coupled into an optically transparent planar waveguide assembly by an input coupling optic, such as an in-coupling diffractive optic, which can be mounted or formed on a surface of the parallel plate planar waveguide or disposed within the waveguide. Such diffractive optics can be formed as, but are not limited to, diffraction gratings or holographic optical elements. For example, the diffraction grating can be formed as a surface relief grating. After propagating along the planar waveguide, the diffracted color image-bearing light can be directed back out of the planar waveguide by a similar output grating, which may be arranged to provide pupil expansion along one or more dimensions of the virtual image. In addition, one or more diffractive turning gratings may be positioned along the waveguide optically between the input and output gratings to provide pupil expansion in one or more dimensions of the virtual image. The image-bearing light output from the parallel plate planar waveguide provides an expanded eyebox for the viewer. Multiple encounters of the image-bearing light along the length of the out-coupling diffractive optic in the direction of propagation have the effect of expanding one direction of the eyebox within which the beams overlap. The expanded eyebox decreases sensitivity to the position of a viewer's eye for viewing the virtual image.
An optical system, such as a HMD, can produce a virtual image. In contrast to methods for forming a real image, a virtual image is not formed on a display surface. That is, if a display surface were positioned at the perceived location of a virtual image, no image would be formed on that surface. Virtual images have a number of inherent advantages for augmented reality presentation. For example, the apparent size of a virtual image is not limited by the size or location of a display surface. Additionally, the source object for a virtual image may be small; for example, a magnifying glass provides a virtual image of an object. In comparison with systems that project a real image, a more realistic viewing experience can be provided by forming a virtual image that appears to be some distance away. Providing a virtual image also obviates the need to compensate for screen artifacts, as may be necessary when projecting a real image.
To couple image content into waveguides, injection optics often use spatial light modulator microdisplays that modulate light incident of each display pixel along with projection optics to create virtual images. However, transmissive spatial light modulators used in this manner can be optically inefficient thereby increasing power requirements of the light source. Consequently, illumination sources such as light emitting diodes (LEDs) must be driven with higher currents, increasing power consumption and heating. Reflective spatial light modulators such as liquid crystal on silicon (LCoS) or DLP (Digital Light Processing) can be optically more efficient and are used in a number of applications such as digital projectors. However, because transmissive or reflective systems modulate incident light rather than emit light, they require additional optics that project, condense, and split output beams from the LED sources. Although much effort in the industry has been devoted to miniaturizing “engines” that integrate displays, sources, projection optics, beam splitters, polarizers, heat sinks, etc., state-of-the-art dimensions are still undesirably large for HMDs. Additional drawbacks associated with current engine technology negatively affect cost, size, weight, and power. Because these displays only modulate incident light, the light source must remain turned on regardless of image content. For example, a bright full-screen virtual image and a simple arrow that takes up only 5% of the display pixels will consume approximately the same power.
Self-emitting displays can circumvent many of the aforementioned problems. Inorganic and organic LED arrays (OLED) produce light on a pixel-by-pixel basis to produce the desired image. Self-emitting pixel-addressable displays such as OLEDs consume power depending on how many pixels are addressed and the specific brightness of each pixel addressed. This pixel-power addressable approach can substantially decrease power consumption. A significant advantage of self-emitting pixel-addressable displays is that such displays do not require projection optics to illuminate the spatial light modulator display. Therefore, no micromirror arrays are required.
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In an embodiment, the backplanes of the LED arrays 30, 32, 34 are actively aligned utilizing images during manufacturing and assembly. The first LED array 30 includes a first backplane, the second LED array 32 includes a second backplane, and the third LED array 34 includes a third backplane. At least during manufacturing and assembly, the first, second, and third LED arrays 30, 32, 34 may be at least partially aligned by shifting and/or rotating the position of the LED backplanes. The LED arrays 30, 32, 34 are aligned such that corresponding pixels from the first, second and third LED arrays 30, 32, 34 are located at the same pixel in the produced image. In an embodiment, as illustrated in
In an embodiment, pixel alignment of the LED arrays 30, 32, 34 is adjusted digitally. Alignment calibration software installed on the processor 14 is operable to control the addressable LEDs of the LED arrays 30, 32, 34 to perform digital pixel alignment. Digital pixel alignment may be utilized instead of alignment with the multi-lens systems 42, 44, 46, or in conjunction with alignment with multi-lens systems 42, 44, 46, and/or in conjunction with alignment of the LED array backplanes. In an embodiment, the LED arrays 30, 32, 34 include a plurality of LED's which do not form part of the virtual display. In other words, the LED arrays 30, 32, 34 include excess LEDs on the margins thereof. In an embodiment, digital pixel alignment utilizes the marginal LEDs to change the ON/OFF pixels to align the green, red, and blue pixels in a generated image.
In an embodiment, the first, second, and third multi-lens systems 42, 44, 46 are actively aligned utilizing images during manufacturing and assembly. Each lens of the multi-lens systems 42, 44, 46 are independently adjustable to align pixels from the first, second and third LED arrays 30, 32, 34. For example, the position of one or more lenses of the multi-lens systems 42, 44, 46 may be adjusted until one or more pixels from the first, second and third LED arrays 30, 32, 34 are coaxially located at the same corresponding pixel on the screen 52. Changing the position of one or more lenses of the first, second, and third multi-lens systems 42, 44, 46 changes the angle of the light emitted for each pixel. In an embodiment, the angle of the light emitted from corresponding individual LEDs of each of the arrays 30, 32, 34 is aligned to be parallel as transmitted through the multi-lens systems 42, 44, 46.
In another embodiment, the LED arrays 30, 32, 34 are aligned utilizing a combination of backplane alignment, alignment of one or more lenses of the first, second, and third multi-lens systems 42, 44, 46, and digital pixel alignment. For example, the LED arrays 30, 32, 34 may be at least partially aligned utilizing backplane alignment, at least partially aligned utilizing adjustment one or more lenses of the first, second, and third multi-lens systems 42, 44, 46, and further aligned utilizing digital pixel alignment.
In one or more embodiments, the shape and orientation of the fixed panel need not be generally rectangular. As illustrated in
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One or more features of the embodiments described herein may be combined to create additional embodiments which are not depicted. While various embodiments have been described in detail above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant arts that the disclosed subject matter may be embodied in other specific forms, variations, and modifications without departing from the scope, spirit, or essential characteristics thereof. The embodiments described above are therefore to be considered in all respects as illustrative, and not restrictive. The scope of the invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/048728 | 9/1/2021 | WO |
Number | Date | Country | |
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63073358 | Sep 2020 | US |