Display device with guide having reflective coating

Abstract

To provide a display device including guides for propagating rays from one or more image sources to an observer by using a combination of refractive index interfaces and reflective coatings.SOLUTION: A display device may include a guide, a back side coating, a front side coating, an input coupler, an output coupler, and an image source. The guide may include a guide front side and a guide back side opposite the guide front side. The back side coating may line the guide back side and may reflect rays in a first waveband. The front side coating may line the guide front side and may reflect rays in a second waveband. The image source may emit rays toward the guide. The input coupler may receive the rays emitted by the image source and couple the rays into the guide. The output coupler may receive rays propagated along the guide between the guide back side and the guide front side and emit the received rays from the guide front side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001]

[0001] Some augmented reality (AR), mixed reality (MR), and virtual reality (VR) devices include visual displays that use light guides or waveguides, collectively referred to as "guides" hereinafter.

Background Art

[0002] Such visual displays generally couple light into a guide, use total internal reflection (TIR) within the guide to propagate such light along the guide to another location, and outcouple the light from the guide to a user. Since confinement within the guide is based on TIR, the refractive index of the material used to implement the guide affects the performance characteristics of the guide. Namely, higher refractive index materials provide a wider range of angles at which light can propagate within the guide, thereby enabling a wider field of view (FOV) or a wider generated image. Furthermore, applications beyond AR, MR, and VR devices can benefit from confinement of light of a certain wavelength or wavelength range within a guide while allowing light of other wavelengths or wavelength ranges to pass through the guide.

[0003]

[0002] However, high refractive index materials (e.g., materials having a refractive index greater than 2) are generally more costly than materials having a lower refractive index. Accordingly, high refractive index materials are generally prohibitively costly for consumer-grade AR devices, MR devices, and / or VR devices. Furthermore, the angular range within which light can be confined by the TIR effect is inherently limited in guides.

Summary of Invention

[0004]

[0003] A display device comprising a guide for propagating light rays from one or more image sources to an observer by using a combination of a refractive index interface and a reflective coating is illustrated and / or described in relation to at least one of the figures and more fully shown in the claims. The reflective coating can complement the refractive index interface and increase the angle at which light rays propagate through the guide. In this way, the display device can achieve a wider field of view (FOV) or wider generated image than is possible with guides formed from other low refractive index materials.

[0005]

[0004] These and other advantages, aspects, and novel features of the present disclosure, as well as details of the illustrated embodiments of the present disclosure, will be better understood from the following description and drawings.

[0005] Various features and advantages of this disclosure can be more easily understood by referring to the following detailed description provided in conjunction with the accompanying drawings, where similar reference numerals indicate similar structural elements. [Brief explanation of the drawing]

[0006] [Figure 1]

[0006] This is a block diagram of a computing device equipped with a display device. [Figure 2A]

[0007] Figure 1 shows one embodiment of a display device suitable for the display device, and the figure shows a display device having a guide with a reflective coating. [Figure 2B]

[0008] Figure 2A is a graph showing the transmission characteristics of the reflective coating for the display device. [Figure 3A]

[0009] Figure 1 shows one embodiment of a display device suitable for the display device, and the figure shows a display device having a guide with a reflective coating. [Figure 3B]

[0010] Figure 3A is a graph showing the transmission characteristics of the reflective coating for the display device. [Figure 4A]

[0011] Figure 1 shows one embodiment of a display device suitable for the display device, and the figure shows the display device having a plurality of guides, each having a reflective coating. [Figure 4B]

[0012] Figure 4A is a graph showing the transmission characteristics of the reflective coatings for each guide in the display device. [Figure 4C] Figure 4A is a graph showing the transmission characteristics of the reflective coatings for each guide in the display device. [Figure 4D] Figure 4A is a graph showing the transmission characteristics of the reflective coatings for each guide in the display device. [Figure 5]

[0013] This figure shows one embodiment of a head-mounted display device suitable for the display device shown in Figure 1. [Figure 6A]

[0014] Figure 6A shows Snell's Law. [Figure 6B] Figure 6B shows the effect of stacking material layers on light rays passing through the material layers. [Figure 7]

[0015] Figures 2A, 3A, 4A, and 5 show how much a reflective coating can increase the angular range over which light rays can be internally reflected by the guides of the display devices. [Modes for carrying out the invention]

[0007]

[0016] The following discussion provides various examples of display devices and various examples of computing devices comprising such display devices. Such examples are non-limiting, and the attached claims should not be limited to the specific examples disclosed. In the following discussion, the terms “example” and “for example” are non-limiting.

[0008]

[0017] The figures illustrate general configurations, and details of explanations and well-known features and techniques may be omitted to avoid unnecessarily obscuring this disclosure. Furthermore, the elements in the drawings are not necessarily to scale. For example, the dimensions of some elements in the drawings may be exaggerated compared to others to help improve the understanding of the examples discussed in this disclosure. The same reference number in different figures represents the same element.

[0009]

[0018] The term "and / or" means any one or more items in a list linked by "and / or". For example, "x and / or y" means any element of the three-element set {(x), (y), (x,y)}. Another example is "x, y, and / or z" meaning any element of the seven-element set {(x), (y), (z), (x,y), (x,z), (y,z), (x,y,z)}.

[0010]

[0019] The terms “comprises,” “comprising,” “includes,” and / or “including” are “open-ended” terms that specify the presence of the listed feature but do not exclude the presence or addition of one or more other features.

[0011]

[0020] Terms such as “first,” “second,” etc., may be used in this specification to describe various elements, and these elements should not be limited by these terms. These terms are used solely to distinguish one element from another. Thus, for example, without departing from the teachings of this disclosure, the first element discussed in this disclosure may be referred to as the second element.

[0012]

[0021] Unless otherwise specified, the term “coupled” may be used to describe two elements that are in direct contact with each other, or two elements that are indirectly connected by one or more other elements. For example, when element A is coupled to element B, element A may be in direct contact with element B, or it may be indirectly connected to element B by an intervening element C. Similarly, the terms “over” or “on” may be used to describe two elements that are in direct contact with each other, or two elements that are indirectly connected by one or more other elements.

[0013]

[0022] Aspects of this disclosure relate to display devices or other devices. Such devices may comprise a guide, a rear coating, a front coating, an input coupler, an output coupler, and an image source. The guide comprises a guide front and a guide rear opposite to the guide front. A rear coating may line or coat the guide rear and reflect light rays in a first wavelength band. A front coating may line or coat the guide front and reflect light rays in a second wavelength band. An image source may emit light rays toward the guide. An input coupler may receive light rays emitted by the image source and couple the light rays into the guide. An output coupler may receive light rays propagated along the guide between the guide rear and the guide front and emit the received light rays from the guide front. Some embodiments of the display device or other devices may utilize other techniques for coupling light into the guide. For example, such a device may place a light source inside the guide and couple the light into the edge of the guide, or use a prism to couple light into the guide. Conversely, some embodiments of display devices or other devices may utilize other techniques for coupling light outside the guide and / or to a sensor. For example, such a device may place a sensor inside the guide and couple the light outside the edge of the guide, or use a prism to couple the light outside the guide.

[0014]

[0023] Further aspects of the present disclosure are directed to a method for a display device or another device. The method may comprise the steps of: emitting light rays from an image source; and coupling light rays from the image source into a guide comprising a guide front surface having a front coating and a guide rear surface having a rear coating. The method may also comprise the steps of: reflecting a first portion of the light rays between the guide front surface and the guide rear surface based on refractive index interfaces of the guide front surface and the guide rear surface; and reflecting a second portion of the light rays between the front coating and the rear coating based on a common reflection wavelength band of the front coating and the rear coating. Furthermore, the method may comprise the step of outcoupling the first portion and the second portion of the light rays out of the guide front surface. Some exemplary methods of the display device or other devices may utilize other techniques for coupling light into the guide. For example, such methods may comprise the step of disposing a light source inside the guide, coupling light into an edge of the guide, or coupling light into the guide using a prism. Conversely, some exemplary methods of the display device or another device may utilize other techniques for coupling light out of the guide and / or to a sensor. For example, such methods may comprise the step of disposing a sensor inside the guide, coupling light out of an edge of the guide, or coupling light out of the guide using a prism.

[0015]

[0024] Referring to FIG. 1, a block diagram of a computing device 100 is shown. The computing device 100 may include one or more processors 110, one or more storage devices 120, a display device 130, and various input / output (I / O) devices 150. In various embodiments, the computing device 100 may be implemented as an augmented reality (AR) device, a mixed reality (MR) device, a virtual reality (VR) device, or some other computing device form factor.

[0016]

[0025] The computing device 100 may include a bus and / or other interconnection that operably couples the processor 110, the storage device 120, the display device 130, and the I / O device 150 to each other. The processor 110 may be configured to execute instructions, manipulate data as a result of executing such instructions, and control the operation of other components of the computing device 100. For this purpose, the processor 110 may include general-purpose processors available from various vendors, such as x86 processors and ARM processors. However, the processor 110 may also be implemented using application-specific processors and / or other analog and / or digital logic circuits.

[0017]

[0026] The storage device 120 may include one or more volatile storage devices and / or one or more non-volatile storage devices. In general, the storage device 120 may store software and / or firmware instructions, and the software and / or firmware instructions may be executed by the processor 110. The storage device 120 may store various types of data that the processor 110 can access, modify, or operate on in response to executing the instructions. For this purpose, the storage device 120 may include random access memory (RAM) devices, read-only memory (ROM) devices, solid-state device (SSD) drives, flash memory devices, and the like. In some embodiments, one or more of the storage devices 120 may be integrated with one or more of the processors 110.

[0018]

[0027] The display device 130 may emit rays of light to present an image and / or other visual output. Specifically, the display device 130 may emit such rays in response to an instruction executed by the processor 110. As will be described in more detail below, the display device 130 may include guides along which rays from an image source propagate to the front of the display device 130.

[0019]

[0028] Other I / O devices 150 may provide devices that enable a user or another device (e.g., another computing device, networking device, etc.) to interact with computing device 100. For example, I / O devices 150 may include buttons, touchscreens, keyboards, microphones, audio speakers, etc., through which a person can interact with computing device 100. I / O devices 150 may also include network interfaces that enable computing device 100 to communicate with other computing devices and / or networking devices. For this purpose, networking interfaces may include wired networking interfaces such as Ethernet (IEEE 802.3) interfaces, wireless networking interfaces such as WiFi (IEEE 802.11) interfaces and Bluetooth (IEEE 802.15.1) interfaces, radio or mobile interfaces such as cellular interfaces (GSM, CDMA, LTE, etc.), and / or any other type of networking interface that can provide a communication link between computing device 100 and other computing devices and / or networking devices.

[0020]

[0029] The above describes embodiments of computing device 100. However, there may be significant variations in the actual implementation of computing device 100. For example, a headset implementation of computing device 100 may use very different components and have a very different architecture than a smartphone implementation of computing device 100. Regardless of such differences, computing devices still generally include a processor that executes software and / or firmware instructions to implement various functions. Therefore, the aforementioned embodiments of computing device 100 are presented not in a restrictive manner, but rather in an overall illustrative manner.

[0021]

[0030] Some aspects of this disclosure may be particularly useful for computing devices implemented as AR devices, MR devices, or VR devices. Some aspects of this disclosure may also be useful for display devices in cell phones, computer monitors, tablets, or other devices that can utilize guides or optical transport layers for optical projection or optical reception. However, this disclosure assumes that the aspects will find usefulness across a vast array of computing devices, computing platforms, and / or other environments, and is not intended to limit the scope of this disclosure to any particular computing device, computing platform, and / or environment beyond any limitations that may be found in the appended claims.

[0022]

[0031] Referring next to Figure 2A, a display device 200 is shown. Display device 200 may be suitable for implementing the display device 130 of Figure 1. Display device 200 may comprise an image source 210, a guide 220, an input coupler 231, an output coupler 232, a rear reflective coating 241, and a front reflective coating 242. The image source 210 may include a liquid crystal display (LCD) device, a liquid-crystal on silicon (LCoS) device, a light-emitting diode (LED) device, an organic light-emitting diode (OLED) device, a quantum dot device, an interference modulator device, or other image generation device.

[0023]

[0032] The guide 220 may comprise one or more dielectric layers defining a guide rear surface 221, a guide front surface 222 opposite to the guide rear surface 221, and a guide side wall 223 between the guide rear surface 221 and the guide front surface 222. The guide 220 may further include an input coupler 231 along the guide rear surface 221 and an output coupler 232 along the guide front surface 222.

[0024]

[0033] The guide 220 may include a rear reflective coating 241 along the rear guide surface 221 and a front reflective coating 242 along the front guide surface 222. The image source 210 may be positioned below or behind the rear guide surface 221 so that the light or other electromagnetic rays 211 emitted by the image source 210 are aligned with the input coupler 231.

[0025]

[0034] The guide rear surface 221, the guide front surface 222, and their respective coatings 241, 242 can cooperate to confine the ray 211 within the guide 220 and to direct the confined ray 211 from the input coupler 231 to the output coupler 232. In various embodiments, the thickness of one or more dielectric layers forming the guide 220 may be defined such that the guide 220 supports the propagation of a discrete set of modes or a continuum of modes.

[0026]

[0035] An input coupler 231 may be positioned along the rear surface 221 of the guide. The input coupler 231 may be constructed to allow rays 211 emitted by the image source 210 to enter the guide 220 through the rear surface 221. In some embodiments, the input coupler 231 may be positioned along other sides and / or surfaces of the guide 220 (e.g., guide sidewall 223) to receive rays 211 emitted by an image source aligned with such sides of the guide 220. Conversely, an output coupler 232 may be positioned along the front surface 222 of the guide. The output coupler 232 may be constructed to allow rays 211 to exit the guide 220 through the front surface 222. In some embodiments, the output coupler 232 may be positioned along other sides and / or surfaces of the guide 220 (e.g., guide sidewall 223) to allow rays 211 to exit through such sides of the guide 220.

[0027]

[0036] Couplers 231, 232 may be prism couplers, diffraction couplers, metasurface couplers, or other types of optical couplers known in the art. Couplers 231, 232 may be embedded in one or more layers of the guide 220, etched into one or more layers of the guide 220, or mounted on the guide front 222, guide rear 221, or guide sidewall 223. Thus, the guide 220 may achieve outcoupling of rays 211 from the guide front 222.

[0028]

[0037] Although shown with a single input coupler 231 and a single output coupler 232, the display device 200 may include multiple input couplers 231 and / or output couplers 232, and thus provide multiple incoupling and / or outcoupling regions in the guide 220. Furthermore, the output coupler 232 may be designed to have multiple outcoupling or uncoupling regions. Multiple outcoupling or uncoupling regions may be useful, for example, to extend the spatial range of the outcoupling area by outcoupling rays with respect to several bounces within the guide 220.

[0029]

[0038] For clarity, Figure 2A shows a single ray 211 generated by the image source 210. However, in various embodiments, the image source 210 may generate several rays 211 within a given field of view (FOV). Furthermore, the image source 210 may generate rays 211 of multiple wavelengths.

[0030]

[0039] The output coupler 232 may be designed to minimize interference with rays from the surrounding environment passing through the guide 220 (e.g., rays from the external world). Hereinafter, such rays will be referred to as world light 280. Specifically, by selecting an appropriate grating pitch and / or reducing the refractive index contrast of the output coupler 232, the output coupler 232 may be positioned without interfering with, or clearly without interfering with, the world light 280. The output coupler 232 may extend to cover a large portion of the guide front 222, or it may be confined to a discrete area of ​​the guide 220 as shown.

[0031]

[0040] If couplers 231 and 232 are implemented as diffraction grating couplers having the same period, the light ray 211 emitted by the display device 200 should be subject to little to no distortion due to diffraction grating dispersion. However, if the period of input coupler 231 differs from the period of output coupler 232, the light ray 211 may be subject to image distortion due to mismatched dispersion of couplers 231 and 232. Similarly, if input coupler 231 is implemented as a prism coupler and output coupler 232 is implemented as a grating coupler, or vice versa, the resulting signal emitted by the display device 200 may be subject to image distortion due to mismatched dispersion of couplers 231 and 232. Therefore, the display device 200 may include other elements, such as optical elements embedded in the guide 220, to compensate for such distortion. Furthermore, software executed by the processor 110 and used to drive the image source 210 may modify the light rays 211 emitted by the image source 210 to compensate for such distortions.

[0032]

[0041] For MR and VR devices, the display device 200 generally provides the observer 290 with rays generated by the image source 210 without the concern of providing the observer 290 with rays from another image source. For example, the display device 200 of an MR or VR device may not provide the observer 290 with world light 280. Therefore, for such a device, the display device 200 does not need to allow the world light 280 to pass through the guide rear surface 221 and proceed from the guide front surface 222 to the observer 290. Thus, the reflective coatings 241, 242 of such a device may each have any broad reflective wavelength band (e.g., the entire visible light wavelength band).

[0033]

[0042] Conversely, in an AR device, the display device 200 may not only provide the observer 290 with light rays emitted from the image source 210, but also provide the observer 290 with world light 280. In such an AR device, the reflective coatings 241, 242 may extend to a portion of the visible light wavelength band, generally allowing the world light 280 to pass through the guide rear surface 221 and out of the guide front surface 222 to reach the observer 290. In this way, the observer 290 can simultaneously observe light rays from both the image source 210 and the surrounding environment. While world light transmission may not be essential for MR and / or VR devices, the reflective coatings 241, 242 of the display device 200 in some embodiments of MR and / or VR devices may similarly extend to a portion of the visible light wavelength band range, as in an AR device.

[0034]

[0043] For example, reflective coatings 241 and 242 may be designed to have high reflectivity (low transmittance) across the green (G) wavelength band and to have an operating angle range generated by the image source 210 and input coupler 231. Furthermore, reflective coatings 241 and 242 may be designed to have high transmittance across other visible light wavelength bands. Due to such reflectivity, reflective coatings 241 and 242 can generally allow world light 280 from the ambient environment to pass through the guide 220 to the observer 290, as well as allow light rays in the green (G) wavelength band to propagate from the image source 210 to the observer 290.

[0035]

[0044] The graph in Figure 2B shows the reflectance of coatings 241 and 242. The values ​​shown for the green (G) wavelength band, the coating reflectance band, and the reflectance / transmission values ​​in the graph are illustrative only and do not limit the present disclosure unless specifically present in the appended claims. In various embodiments, coatings 241 and 242 may compensate for possible batch-to-batch variations and / or temperature variations of green (G) wavelength band light emitted by the image source 210. Similarly, the reflectance wavelength bands of coatings 241 and 242 may compensate for possible temperature shifts and changes in the angle of incidence of light to coatings 241 and 242.

[0036]

[0045] In various embodiments, coatings 241 and 242 are implemented similarly. Therefore, coatings 241 and 242 provide the same or substantially the same reflection wavelength band and thus cooperate to propagate rays 211 within the reflection wavelength bands of coatings 241 and 242. In some embodiments, coatings 241 and 242 may provide different reflection wavelength bands. In such embodiments, coatings 241 and 242 may cooperate to propagate rays 211 within a common wavelength band (e.g., a portion of two overlapping wavelength bands).

[0037]

[0046] In various embodiments, coatings 241 and 242 may comprise alternating layers of dielectric and / or metallic materials with different refractive indices. For example, coatings 241 and 242 may comprise alternating layers of high-refractive-index and low-refractive-index materials. In such embodiments, the high-refractive-index material may be selected from tantalum oxide, titanium oxide, silicon carbide, silicon nitride, aluminum nitride, and the like. The low-refractive-index material may be selected from epoxy, aluminum oxide, silicon oxide, and the like.

[0038]

[0047] The alternating layer structure can provide the coatings 242, 242 with a reflective structure in which the alternating layers have a layer thickness of approximately constant wavelengths for which light of the corresponding wavelengths is reflected. For example, the region of interest may comprise a quarter-wavelength stack having a layer thickness of one-quarter of the reflected wavelength. In such embodiments, to reduce the width of the region, the layers of the stack may be shifted from a quarter-wavelength such that one of the layer types (e.g., a high-refractive-index material layer or a low-refractive-index material layer) provides a layer thickness of about 1.5 times or more a quarter-wavelength, while the other layer types provide layer thicknesses reduced from a quarter-wavelength to less than one-tenth of a quarter-wavelength.

[0039]

[0048] A guide 220 formed from a high refractive index material (for example, a material with a refractive index greater than 2) can propagate light rays over a wider angular range than a guide 220 formed from a low refractive index material. A wider angular range may be desirable to provide a wider field of view (FOV) to the display device 200, but high refractive index materials are generally more expensive than low refractive index materials. Furthermore, simply forming the guide 220 from several layers of low refractive index material does not provide the wider angular range over which light rays propagate through the guide 220.

[0040]

[0049] A layer of material 601 is shown in Figure 6A, and a light ray exits the surrounding medium 603 at an angle A1 within the medium with respect to the normal. If material 601 has a refractive index N1 and the surrounding medium 603 has a refractive index N3, and a layer of material 602 with refractive index N2 is added, the final exit angle A3 does not change. See, for example, Figure 6B. According to Snell's Law, N1*sin(A1)=N2*sin(A2)=N3*sin(A3) Therefore, simply stacking an additional layer of low refractive index material on top of the guide 220 may not improve the field of view of the display device 200.

[0041]

[0050] Therefore, the display device 200 includes reflective coatings 241, 242 to supplement or increase the angular range reflected by the guide 220 due to the refractive index interface. As shown in Figure 7, the refractive index interface of the guide 220 may provide a first angular range 701 in which light rays are internally reflected. Coatings 241, 242 may be designed to internally reflect light rays in a second angular range 702. As illustrated, the reflective coatings 241, 242 may be designed such that the second angular range 702 includes additional angles not present within the first angular range 701 provided by the refractive index interface. For this purpose, the ranges 701, 702 may be separate or partially overlapping. The net result is that the refractive index interface and coatings 241, 242 work together to improve the angle in which light rays 211 are internally reflected, and thus provide the display device 200 with a wider field of view.

[0042]

[0051] Referring next to Figure 3A, another embodiment of the display device is shown. Display device 201 may be suitable for implementing display device 130 of Figure 1. As shown, display device 201 may comprise an image source 210, a guide 220, an input coupler 231, an output coupler 232, a rear reflective coating 243, and a front reflective coating 244. The image source 210 may include a liquid crystal display (LCD) device, a liquid-crystal on silicon (LCoS) device, a light-emitting diode (LED) device, an organic light-emitting diode (OLED) device, a quantum dot device, an interference modulator device, or other image generation device.

[0043]

[0052] Display device 201 can be implemented in a similar manner to display device 200. However, the coatings 243 and 244 of display device 201 differ from those of display device 200. Specifically, in addition to the green (G) wavelength band of coatings 241 and 242, coatings 243 and 244 can be designed to have high reflectivity (low transmittance) across the red (R) and blue (B) wavelength bands. Furthermore, reflective coatings 243 and 244 can be designed to have high transmittance across other visible light wavelength bands. Due to such reflectivity, reflective coatings 243 and 244 can generally allow world light 280 from the ambient environment to pass through guide 220 to observer 290, while red (R), green (G), and blue (B) wavelength rays can propagate from image source 210 to observer 290.

[0044]

[0053] The graph in Figure 3B shows the reflectance of coatings 243, 244. The values ​​shown for the red (R), green (G), and blue (B) wavelength bands, the coating reflectance bands, and the reflectance / transmission values ​​in the graph are illustrative only and do not limit this disclosure unless specifically present in the appended claims. In various embodiments, coatings 243, 244 may compensate for possible batch-to-batch variations and / or temperature variations in the red (R), green (G), and / or blue (B) wavelength bands emitted by the image source 210. Similarly, the reflectance wavelength bands of coatings 243, 244 may compensate for possible temperature shifts and changes in the angle of incidence of the light to coatings 243, 244.

[0045]

[0054] Referring next to Figure 4A, another embodiment of the display device is shown. Display device 202 may be suitable for implementing display device 130 of Figure 1. As shown, display device 202 may comprise image sources 210r, 210g, 210b, guides 220r, 220g, 220b, input couplers 231r, 231g, 231b, output couplers 232r, 232g, 232b, rear reflective coatings 241r, 241g, 241b, and front reflective coatings 242r, 242g, 242b. The image sources 210r, 210g, 210b may be located below or behind the rear guide 221r.

[0046]

[0055] Each guide 220r, 220g, and 220b may be implemented in the same manner as the guide 220 of the display device 200. Specifically, each guide 220r, 220g, and 220b may have its respective guide rear surface 221r, 221g, and 221b, its respective guide front surface 222r, 222g, and 222b on the opposite side of its respective guide rear surface 221r, 221g, and 221b, and its respective guide side wall 223r, 223g, and 223b between its respective guide rear surface 221r, 221g, and 221b and its respective guide front surface 222r, 222g, and 222b. Each guide 220r, 220g, 220b may further include input couplers 231r, 231g, 231b along the rear surface 221r, 221g, 221b of the guide, and output couplers 232r, 232g, 232b along the front surface 222r, 222g, 222b of the guide.

[0047]

[0056] Each guide 220r, 220g, 220b may include a rear reflective coating 241r, 241g, 241b along the rear guide surfaces 221r, 221g, 221b, and a front reflective coating 242r, 242g, 242b along the front guide surfaces 222r, 222g, 222b. Each image source 210r, 210g, 210b may be positioned below or behind the rear guide surface 221r ​​so that the rays 211r, 211g, 211b emitted by the image sources 210r, 210g, 210b are aligned with their respective input couplers 231r, 231g, 231b. In this way, the rays 211r, 211b, 211g can be incoupled to their respective guides 220r, 220b, 220g. Although shown as three separate image sources, in some embodiments, image sources 210r, 210g, and 210b may be provided by a single imaging device.

[0048]

[0057] The output couplers 232r, 232g, and 232b of guides 220r, 220g, and 220b can be positioned perpendicular to each other so that the outcoupled rays of the lower guide pass through the output couplers of the upper guides. Specifically, guide 220b may be positioned above guide 220g, and the output coupler 232b of guide 220b may be positioned above the output coupler 232g of guide 220g. Furthermore, guide 220g may be positioned above guide 220r, and the output coupler 232g of guide 220g may be positioned above the output coupler 232r of guide 220r. In this way, the outcoupled rays 211r of guide 220r can pass through guides 220g and 220b positioned above guide 220r, and through their respective output couplers 232g and 232b positioned above guide 220r. Similarly, the outcoupled ray 211g of guide 220g can pass through guide 220b, which is positioned above guide 220g, and its output coupler 232b. Thus, observer 290 can receive rays 211r, 211g, and 211b from image sources 210r, 210g, and 210b via the front surface 222b of guide.

[0049]

[0058] The display device 202 can transport light rays 211r, 211b, and 211g from image sources 210r, 210g, and 210b to the observer 290. Specifically, the display device 202 can couple the light rays 211r, 211g, and 211b into their respective guides 220r, 220g, and 220b via input couplers 231r, 231g, and 231b. The combined internal total internal reflection (TIR) ​​of the guides 220r, 220g, and 220b, along with the reflectivity of their coatings, can confine the light rays 211r, 211g, and 211b and propagate them from the input couplers 231r, 231g, and 231b to the output couplers 232r, 232g, and 232b. The output couplers 232r, 232g, and 232b can then emit or outcouple rays 211r, 211g, and 211b from their guide fronts 222r, 222g, and 222b to the observer 290.

[0050]

[0059] As shown in Figure 4A, the display device 202 may support three different wavelength bands (e.g., red, green, and blue). However, the display device 202 can be implemented with any number of wavelength bands by using an appropriate number of guides. Furthermore, in exemplary embodiments, guide 220b includes a guide front 222b that interfaces with the external environment (e.g., air). In some embodiments, an air gap is maintained between each guide 220r, 220g, 220b to ensure that both the guide fronts 222r, 222g, 222b and the guide rears 221r, 221g, 221b interface with a medium having the same refractive index (e.g., air). This ensures that the front and rear surfaces of each guide 220r, 220g, 220b achieve the same internal refraction.

[0051]

[0060] The graph in Figure 4B shows the reflectance of coatings 241r and 242r. The graph in Figure 4C shows the reflectance of coatings 241g and 242g. The graph in Figure 4D shows the reflectance of coatings 241b and 242b. The values ​​shown for each wavelength band (e.g., red (R), green (G), and blue (B)), the coating reflectance bands, and the reflectance / transmittance values ​​in the graphs are illustrative only and do not limit this disclosure unless specifically present in the appended claims. In various embodiments, the coatings may compensate for possible inter-batch variations and / or temperature variations in the wavelength band of light emitted by the respective image sources 210r, 210g, and 210b. Similarly, the reflectance wavelength bands of coatings 241r, 241g, 241b, 242r, 242g, and 242g can compensate for possible temperature shifts and changes in the angle of incidence of light rays to coatings 241r, 241g, 241b, 242r, 242g, and 242g.

[0052]

[0061] Referring next to Figure 5, another embodiment of the display device is shown. Display device 203 may be suitable for implementing the display device 130 of Figure 1. Display device 203 may comprise a first display device 203R for the first eye 290R of observer 290 and a second display device 203L for the second eye 290L of observer 290. In various embodiments, display device 203 may be implemented as a head-mounted device such as glasses, a visor, a headset, or other AR / MR / VR display device shape factor. For this purpose, display device 203 may comprise a frame 205 having arms 207R, 207L and a bridge 209. The arms 207R, 207L are positioned close to the outer ends of display devices 203R, 203L, and the bridge 209 may span between the inner ends of display devices 203R, 203L. Frame 205 can hold the first display device 203R and the second display device 203L and be positioned on the face of observer 290. Specifically, observer 290 positions arms 207R, 207L above observer 290's ears and bridge 209 above the nasal bridge of observer 290's nose, positioning the first display device 203R and the second display device 203L in front of observer 290's eyes 290R, 290L, respectively.

[0053]

[0062] As shown in the figures, each display device 203R, 203L can be implemented in the same manner as display device 200. That is, the first display device 203R may include an image source 210R, a guide 220R, an input coupler 231R, an output coupler 232R, a rear reflective coating 241R, and a front reflective coating 242R. Similarly, the second display device 203L may include an image source 210L, a guide 220L, an input coupler 231L, an output coupler 232L, a rear reflective coating 241L, and a front reflective coating 242L.

[0054]

[0063] In some embodiments, the display device 203 may include additional AR / MR / VR components such as an eye-tracking module, a 3D sensing module, a remote controller module, a video camera, a microphone, and / or a speaker. In AR applications, the display devices 203R, 203L may be implemented to allow world light 280 to pass through their respective guides 220R, 220L to the observer's eyes 290R, 290L. In VR or MR applications, the display devices 203R, 203L may be implemented to prevent world light 280 from passing through their respective guides 220R, 220L. Accordingly, the coatings 241R, 241L, 242R, 242L may be implemented with a high-reflectivity wavelength band wider than the green (G) wavelength band of the display device 200. In some embodiments, the high-reflectivity wavelength band of the coatings 241R, 241L, 242R, 242L may extend to the entire visible light wavelength band.

[0055]

[0064] This disclosure includes references to several examples, but those skilled in the art will understand that various modifications may be made and equivalents may be substituted without departing from the scope of this disclosure. Furthermore, modifications may be made to the disclosed examples without departing from the scope of this disclosure. For example, display devices 200, 201, 202, and 203 possess various described features. Additional display device embodiments may mix, adapt, and / or combine the features of display devices 200, 201, 202, and 203. Accordingly, the appended claims are not limited to the disclosed examples but encompass all embodiments that fall within their respective scopes. [Explanation of Symbols]

[0056] 100 Computing Devices 110 processors 120 Storage Devices 130 Display Devices 150 Input / Output (I / O) Devices 200 display devices 201 Display Devices 202 Display Devices 203 Display Devices 205 frame 207 Arm 209 Bridge 210 Image Sources 220 Guide 221 Guide rear 222 Guide front 223 Guide sidewall 231 Input Coupler 232 Output coupler 241 Rear reflective coating 242 Front reflective coating 243 Rear reflective coating 244 Front reflective coating 280 World Light 290 Observers 601 Material 603 Peripheral media

Claims

1. A guide comprising a front surface and a rear surface opposite to the front surface, A rear coating comprising alternating layers of dielectric and / or metallic materials with different refractive indices, configured to reflect light rays in a first wavelength band along the rear surface of the guide, A front coating comprising alternating layers of dielectric and / or metallic materials with different refractive indices, configured to reflect light rays in a second wavelength band along the front surface of the guide, An output coupler configured to receive a ray propagated along the guide and emit the received ray from the front of the guide, A device equipped with, The front surface of the guide and the rear surface of the guide each provide a refractive index interface that internally reflects a first portion of the light ray within a first angular range. The front coating and the rear coating each provide internal reflection to a second portion of the light rays within a second angular range. The light ray emitted from the output coupler includes a first ray from the first portion of the light ray reflected by the front and rear surfaces of the guide, and a second ray from the second portion of the light ray reflected by the front coating and rear coating. device.

2. The device according to claim 1, An image source configured to emit light rays toward the aforementioned guide, An input coupler configured to receive the light ray emitted by the image source and couple the light ray into the guide, A device equipped with the following features.

3. A device according to claim 1, wherein the first angular range and the second angular range overlap.

4. A device according to claim 1, wherein the first angular range and the second angular range do not overlap.

5. The device according to claim 1, wherein the second angular range is at least partially outside the first angular range.

6. A device according to claim 1, wherein the front coating and the rear coating each comprise a plurality of dielectric layers.

7. A device according to claim 1, wherein the front coating and the rear coating each comprise a plurality of metal layers.

8. A device according to claim 1, wherein the first wavelength band and the second wavelength band overlap.

9. A device according to claim 1, wherein the first wavelength band and the second wavelength band are substantially identical.

10. The device according to claim 1, The rear coating is configured to reflect light rays from a first plurality of non-overlapping wavelength bands, including the first wavelength band. The front coating is configured to reflect light rays from a second plurality of non-overlapping wavelength bands, including the second wavelength band. device.

11. A device according to claim 10, wherein each wavelength band of the first plurality of non-overlapping wavelength bands is substantially identical to the corresponding wavelength band of the second plurality of non-overlapping wavelength bands.

12. The device according to claim 2, Each second guide comprises a second guide front surface that provides a refractive index interface for internally reflecting light rays, and a second guide rear surface opposite to the second guide front surface, A second rear coating is provided along the rear surface of the second guide, configured to reflect light rays in a third wavelength band, and comprising alternating layers of dielectric and / or metallic materials with different refractive indices. A second front coating is provided along the front surface of the second guide, configured to reflect light rays in a fourth wavelength band, and comprising alternating layers of dielectric and / or metallic materials with different refractive indices. A second image source configured to emit a ray toward the second guide, A second input coupler configured to receive the light ray emitted by the second image source and to couple the light ray into the second guide, A second output coupler configured to receive a ray propagated along the second guide between the rear surface of the second guide and the front surface of the second guide, and to emit the received ray from the front surface of the second guide. A device equipped with the following features.

13. The device according to claim 12, comprising a frame, the frame is A first arm adjacent to the first end of the guide, A second arm adjacent to the first end of the second guide, The bridge between the second end of the guide and the second end of the second guide A device that includes this.

14. The device according to claim 12, The rear surface of the second guide is positioned on the front surface of the guide. The second input coupler is positioned between the rear surface of the second guide and the front surface of the guide. The output coupler is positioned between the rear surface of the second guide and the front surface of the guide. device.

15. The device according to claim 14, wherein an air gap is provided between the rear surface of the second guide and the front surface of the guide.

16. The device according to claim 12, A third guide comprising a third guide front surface that provides a refractive index interface for internally reflecting light rays, and a third guide rear surface opposite to the third guide front surface, A third rear coating is provided along the rear surface of the third guide, configured to reflect light rays in a fifth wavelength band, and comprising alternating layers of dielectric and / or metallic materials with different refractive indices. A third front coating is provided along the front surface of the third guide, configured to reflect light rays in the sixth wavelength band, and comprising alternating layers of dielectric and / or metallic materials with different refractive indices. A third image source configured to emit a ray toward the third guide, A third input coupler configured to receive the light ray emitted by the third image source and to couple the light ray into the third guide, A third output coupler configured to receive a ray propagated along the third guide between the rear surface of the third guide and the front surface of the third guide, and to emit the received ray from the front surface of the third guide. A device equipped with the following features.

17. The device according to claim 16, The first wavelength band and the second wavelength band correspond to the red wavelength band, The third and fourth wavelength bands correspond to the green wavelength band. The fifth and sixth wavelength bands correspond to the blue wavelength band. device.

18. A device according to claim 16, comprising an imaging device, wherein the imaging device includes the image source, the second image source, and the third image source.

19. The device according to claim 1, The aforementioned front coating allows light in the third wavelength band to pass through the front coating. The rear coating allows light in the fourth wavelength band to pass through the rear coating. device.

20. The steps include: emitting a ray of light from the image source, The steps include coupling the light ray from the image source into a guide having a front surface coating with alternating layers of dielectric and / or metallic materials of different refractive indices, and a rear surface coating with alternating layers of dielectric and / or metallic materials of different refractive indices. A step of reflecting the first portion of the light ray between the front and rear guide surfaces based on refractive index interfaces provided by the front and rear guide surfaces, respectively, which internally reflect the first portion of the light ray within a first angular range, Based on the internal reflection provided by the front coating and the rear coating, the steps include reflecting a second portion of the light rays within a second angular range between the front coating and the rear coating, A step of outcoupling a first ray from the first portion of the ray and a second ray from the second portion of the ray from the front surface of the guide. A method that includes this.

21. A method according to claim 20, wherein the first angular range and the second angular range overlap.

22. A method according to claim 20, wherein the first angular range and the second angular range do not overlap.

23. The method according to claim 20, A step of emitting a second image source ray from a second image source, The steps of coupling the second image source ray into a second guide comprising a second guide front having a second front coating comprising alternating layers of dielectric and / or metallic materials of different refractive indices, and a second guide rear having a second rear coating comprising alternating layers of dielectric and / or metallic materials of different refractive indices, A step of reflecting a first portion of the second image source ray within a third angular range between the second guide front surface and the second guide rear surface based on the refractive index interface of the second guide front surface and the second guide rear surface, The steps include reflecting a second portion of the second image source ray within a fourth angular range between the second front coating and the second rear coating based on the common reflection wavelength band of the second front coating and the second rear coating, The steps include outcoupling the first and second portions of the second image source ray from the front surface of the second guide, A method that includes this.

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