Waveguide configuration

Abstract

According to an example aspect of the present invention, there is provided a light guide arrangement comprising an optical system configured to generate a configurable image encoded in a light field, and at least one light guide arranged to receive light from the light field and transmit light to a plurality of locations in the light guide for emission, creating a waveguide-based display, the optical system comprising a set of light sources, each one of the light sources configured to generate light of a distinct spectral characteristic in the visible spectrum, and the optical system configured to generate the same color in two angular planes of the light field using two different combinations of the light sources.

Description

[Technical field]

[0001] FIELD This disclosure relates to managing colored light using light guides. [Background technology]

[0002] Light guides are capable of transmitting light at optical frequencies. Optical or visible frequencies refer to light having wavelengths between about 400 and 700 nanometers. Light guides are employed in displays where light from a primary display may be transmitted using one or more waveguides to a suitable location for emission to a user's eye or eyes.

[0003] Light guide displays may be mounted in head mounted glasses or helmets and may be suitable for augmented reality or virtual reality type applications. In augmented reality, a user sees a view of the real world with a complementary display overlaid on top. In virtual reality, a user loses their view of the real world and is instead provided with a view into a software defined landscape. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Application No. 15812618.5 [Non-patent literature]

[0005] [Non-Patent Document 1] https: / / www.optilayer.com / notch-filters Summary of the Invention [Means for solving the problem]

[0006] Some aspects provide the subject matter of the independent claims. Some embodiments are defined in the dependent claims.

[0007] According to a first aspect of the present disclosure, there is provided a light guide arrangement comprising: an optical system configured to generate a configurable image encoded in a light field; and at least one light guide arranged to receive light from the light field and to transmit light to a plurality of locations in the light guide for emission, creating a waveguide-based display; the optical system comprising a set of light sources, each one of the light sources configured to generate light of a distinct spectral characteristic in the visible spectrum; and the optical system configured to generate the same color in two angular aspects of the light field using two different combinations of the light sources.

[0008] According to a second aspect of the present disclosure, there is provided a method comprising: generating a configurable image encoded in a light field using an optical system; receiving light from the light field into at least one light guide and transmitting the light to a plurality of locations in the light guide for emission to create a waveguide-based display, wherein the optical system comprises a set of light sources, each of the light sources configured to generate light of distinct spectral characteristics in the visible spectrum, and the method comprises using two different combinations of the light sources to generate the same color in two angular planes of the light field.

[0009] According to a third aspect of the present disclosure, there is provided an apparatus for generating a configurable image encoded in a light field using an optical system, comprising means for receiving light from the light field into at least one light guide and transmitting the light to a plurality of locations for emission in the light guide to create a waveguide-based display, wherein the optical system comprises a set of light sources, each of the light sources configured to generate light of distinct spectral characteristics in the visible spectrum, and the optical system configured to generate the same color in two angular planes of the light field using two different combinations of the light sources.

[0010] According to a fourth aspect of the present disclosure, there is provided a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least generate a configurable image encoded in a light field using an optical system, receive light from the light field into at least one light guide, and transmit the light in the light guide to a plurality of locations for emission to create a waveguide-based display, wherein the optical system comprises a set of light sources, each of the light sources configured to generate light of distinct spectral characteristics in the visible spectrum, and the set of computer readable instructions is configured to use the optical system to generate the same color in two angular planes of the light field using two different combinations of the light sources.

[0011] According to a fifth aspect of the present disclosure there is provided a computer program configured to perform the method according to the second aspect. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 illustrates an example system in accordance with at least some embodiments of the present invention. [Figure 2A] FIG. 1 illustrates an example system in accordance with at least some embodiments of the present invention. [Figure 2B] FIG. 1 illustrates an example system in accordance with at least some embodiments of the present invention. [Diagram 3] FIG. 1 illustrates an example device capable of supporting at least some embodiments of the present invention. [Figure 4] 1 is a flow diagram of a method in accordance with at least some embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The term "color space" refers to a (two-dimensional) chromaticity diagram that corresponds to the perceived colors resulting from the spectral response of the average human eye. The color gamut of a device is the region of the color space that is reproducible by that device. Specifically, the color gamut here corresponds to the region in the color space that can be reproduced by a combination of light source and waveguide, such as light source 140 and waveguide 110 in FIG. 1 in the system, for a light field that an observer perceives as emanating from a focal plane. A Region of Interest (ROI) then refers to the region of the color space that is sufficient to reproduce what is perceived as a full-color image, but may correspond to a smaller or larger region of the color space. Since a particular point in the color space can be reached by different combinations of wavelengths, a particular ROI can be reached using different combinations of distinct spectral features, such as peaks in the visible spectrum.

[0014] A color image can be generated, for example, by assuming that the user's color vision perception corresponds to a standard eye, and by reproducing (a part of) the corresponding color space. As is clear from the definition of the color space, the user perceives the same color as a result of several different optical signal spectra. This allows freedom in how the waveguide operates. In addition, different combinations of distinct spectral characteristics, such as wavelengths, can be used to generate the same color or to provide the same color perception, for example according to the CIE color space. In general, the user can perceive the same color from several spectra of optical signals. This allows freedom in the manufacture of the waveguide.

[0015] By using more than three light sources, such as lasers or light emitting diodes (LEDs), improved waveguide-based displays can be constructed as described herein below. In particular, using a set encompassing more than three visible light sources to generate a single perceived color in a waveguide-based display, color uniformity across the image of the waveguide-based display can be improved since propagation errors in the color of one or more waveguides can be pre-corrected or at least partially avoided by using an appropriate combination of wavelengths from the set of visible light sources to generate a color desired to be presented to a user at a given location of the waveguide-based display. For example, a particular shade of red can be generated by using a set of a first red, a first green, and a first blue in one portion of the waveguide-based display and a second red, a first green, and a second blue in another portion of the waveguide-based display. However, typically a more complex mix of wavelengths is used. In particular, each of the light sources may generate a spectrum of light with one or more peaks, and colors are generated using different combinations of these light sources. The user is thereby presented with a more uniform and reliable image across the area of ​​the waveguide-based display. The spectrum produced by the light source may be referred to as a spectral characteristic, which may be monochromatic, narrowband, broadband, or multi-peak spectral output. Monochromatic may mean, for example, that the bandwidth of the light produced by the light source is, for example, less than 0.1 nanometers, or less than 2 nanometers. In some embodiments, a partial range color space is produced, such as when the waveguide-based display is monochromatic. Alternatively, a white point region may be of interest, with other parts of the color space being outside the range of the waveguide-based display.

[0016] FIG. 1 illustrates an example system in accordance with at least some embodiments of the present invention. The system comprises a set of light sources 140. The light sources 140 may include, for example, laser or LED light sources, with laser light sources having the advantage that they are more strictly monochromatic than LEDs. The light sources 140, together with an optional mirror 130, are configured to create a light field in angular space that can be used to cause a waveguide display to generate its image. The image is encoded in the light field. The light field is illustrated diagrammatically as field 100 in FIG. 1. In some embodiments, a physical primary display may display the image of the light field, while in other embodiments, the system does not include a physical primary display and the image is simply encoded in the light field distributed in angular space. Light 104 from the light field 100 may be conveyed to the light guide 110 directly or using a light guide 102, for example comprising mirrors and / or lenses. The light guides 102 are optional in the sense that they may not be present, depending on the specifications of a particular embodiment. In other words, the light guide 102 is not present in all embodiments. To guide the light 104 into the waveguide 110, an in-coupling structure, such as a partially reflecting mirror, a surface relief grating, or other diffractive structure, as known in the art, may be used to direct the incoming light into the waveguide 110. In some embodiments, the light 104 may be in-coupled from an end of the waveguide.

[0017] In the waveguide 110, the light 104 travels forward by being repeatedly reflected inside the waveguide, interacting with elements 112a until it interacts with elements 112, thereby deflecting the light 104 from the waveguide 110 into air towards the eye 120 as light rays 114 creating an image. Elements 112a and 112a may include, for example, partially reflective mirrors, surface relief gratings, or other diffractive structures. Elements 112a may be arranged to develop a light field 100 inside the waveguide 110, for example, such that the image of the waveguide display is precisely generated. Light from different angular aspects of the light field 100 interacts with elements 112 such that light rays 114 create an image encoded in the light field 100 on the retina of the eye 120. Light may interact with elements 112 in separate sequences, and not all elements 112 are necessarily used at all times. Not all light necessarily needs to hit all elements 112. The element 112 causes the light to exit the waveguide 110 at the exit position. As a result, the user perceives the image encoded in the light field 100 in front of the user's eye 120. Since the waveguide 110 may be at least partially transparent, the user can also advantageously see the user's real surroundings through the waveguide 110, for example, when the waveguide-based display is head-mounted. Light is emitted from the waveguide 110 at multiple angles at multiple positions of the element 112 as a result of the action of the elements 112a and 112. A color image is generated, for example, by assuming that the user's color vision perception corresponds to a standard eye. In general, the user can perceive the same color from multiple spectra of the light beam 114. This provides a degree of freedom in the manufacture of the waveguide 110.

[0018] In a waveguide-based display, multiple waveguides 110 may be present, for example to enhance capabilities and, optionally, to transmit light for a user's other eye, which is not illustrated in FIG. 1 for clarity of illustration.

[0019] The image-encoding light field 100 may be generated using an optical system comprising, for example, a mirror 130, as well as a light source 140. The mirror 130 may comprise, for example, a microelectromechanical (MEMS) mirror configured to reflect light from a light source 140, such as a laser, to generate the image-encoding light field 100 in a controlled manner, for example by scanning an angular space, thereby generating the image-encoding light field 100. The mirror 130 may thus be actuated to tilt at different angles to direct light from the light source 140 to appropriate portions of the light field 100 in angular space. In some embodiments, the optical system may comprise other types of image generating devices, such as a projector, where the light source may be, for example, an LED, and the primary display may be in the form of an LCOS device. The optical system may comprise, for example, a light source and a MEMS actuator configured to provide light from the light source in angular space, thereby generating a light field for input to the waveguide 110.

[0020] The system illustrated in FIG. 1 includes six light sources 140. This is an illustrative example that does not limit the disclosure, rather there may be fewer or more than six light sources. In some embodiments, there are at least four light sources. In some embodiments, the system includes between two and six light sources. The light sources 140 may be monochromatic in the sense that they generate a narrow spectral band of light with a single peak wavelength, as in lasers, or their spectral band may be broader, as with LEDs. Light sources with more complex spectral distributions are also possible. In principle, any color space that humans can see can be generated by appropriately exciting the photoreceptors of the retina. Typically, this is achieved by mixing three wavelengths of light, for example, one wavelength each in the red, green, and blue portions of the spectrum. It can also be done by mixing light from three light sources with a more complex spectrum.

[0021] To create the color image encoded in the light field 100 in angular space, the light source 140 can be controlled, for example, by a program. In examples where a mirror 130 is present, the light source 140 and the mirror 130 can be synchronized with each other such that the light from the light source 140 illuminates a particular angular region of the angular space in a controlled manner to create therein a display of a color image that reproduces a still or moving input image received from an external source, such as a virtual reality or augmented reality computer. The still or moving image received from the external source can include, for example, a digital image or a digital video feed. The image encoded in the light field 100 can thus be constructed by providing an appropriately selected input image.

[0022] To create a particular color at a given face in angle space, that given face in angle space may be illuminated by one or a set of light sources 140, or by three or more light sources 140. That particular color is then reproduced by light ray 114 when light from the given face in angle space travels within waveguide 110 to element 112, where it is emitted at an angle corresponding to the given face in angle space.

[0023] The challenge in accurately reproducing the image encoded in light field 100 by light rays 114 derives from the fact that light of different wavelengths and different propagation angles typically has different transfer functions through the system, which in turn is a function of the position on the surface of the waveguide where the light rays exit the waveguide through element 112. As a result, the colors observed by eye 120 are not perfect reconstructions of the colors in light field 100; in addition, the error is a function of both angular orientation and exit position, which means that the quality and intensity of the color reproduction varies across the image and according to the position of the observer's eye. The solution devised in this disclosure attempts to alleviate this challenge and improve color reproduction in waveguide displays.

[0024] To improve the rendering of the image encoded in the light field 100 to the directed light 114, a particular color can be created in the light field 100 using multiple combinations of light sources 140. Each combination used can be a different weighted sum of a set of light sources 140. Thus, for example, if it is known how the spectrum of the light in the light field 100 changes as a function of the exit position and angular orientation, then a combination of wavelengths can be selected for color reproduction, thereby at least partially pre-correcting for the spectral change undergone in the waveguide. This spectral change can be, for example, pre-mapped experimentally to allow for its pre-correction in the light field 110. This is illustrated in more detail in relation to FIG. 2. In general, each color in a particular color range can be created in this way by using multiple combinations of light sources. One combination of light sources may be employed in one embodiment of the light field 100, and another combination of light sources may be employed to create the same particular color in another embodiment of the light field 100. In some embodiments, the same color in one aspect of the light field 100 can be created using multiple different combinations of light sources. For example, the same or nearly the same image perception can be produced using multiple combinations of light sources. In some embodiments, color modification can be achieved when optimizing the waveguide structure, taking advantage of the freedom provided by the combination of multiple light sources in reproducing (essentially) the same color stimulus. Thus, technical advantages are obtained by increasing the flexibility in designing the waveguide structure.

[0025] The programmable control mechanism can be used to automatically select which combination of light sources to use for which angular aspect of the light field 100 to create a suitable rendering of the image encoded in the light field 100 in the directed light 114. The programmable control mechanism can be pre-configured with combinations of light sources associated with angular aspects of the light field 100. As a result, the use of more than, for example, three light sources as the light sources 140 provides the technical effect and benefit of improving the image quality provided by the waveguide-based display. This is a result of having more component wavelengths to choose from, thereby allowing for a more effective distribution of color components in the waveguides of the display. The combination of light sources can include, for example, a linear mix or weighted sum of two, three or four light sources from all of the light sources 140. In some embodiments, the combination can be a continuous function of angle and / or position. In general, the combination of light sources can include three up to all of the light sources 140. The number of light sources 140 can be, for example, four, five or six.

[0026] In some embodiments, the combinations of light sources used to generate a particular color each include three of the light sources 140. In other embodiments, the combinations of light sources used to generate a particular color each include more than three of the light sources 140. For example, if the light sources 140 include more than four light sources, at least one of the sets includes more than four light sources, up to four light sources from all of the light sources 140. In some embodiments, the combinations used include a weighted combination of all the light sources 140. In some cases, fewer than three light sources can be used to generate a particular color, depending on the specific color and spectrum of the light sources. In some embodiments, a color impression in a sub-portion of the overall visible color space may be reproduced using multiple combinations of light sources, each of which includes, for example, two light sources.

[0027] 2A and 2B illustrate an example system according to at least some embodiments of the present invention. Similar numbering indicates similar structures as in FIG. 1. In FIG. 2A, six light sources 140 are individually identified as light source 140a, light source 140b, light source 140c, light source 140d, light source 140e, and light source 140f. For example, light source 140a and light source 140b may be broadly in the red portion of the visible spectrum, light source 140c and light source 140d may be broadly in the green portion of the visible spectrum, and light source 140e and light source 140f may be broadly in the blue portion of the visible spectrum. In general, the light sources may be in the visible portion of the spectrum.

[0028] In FIG. 2A, light sources 140a, 140c and 140e are used to generate a particular color in the angular aspect 100a of the light field 100. The particular color is determined by the relative intensities of light sources 140a, 140c and 140d, and the brightness of the color is determined by the sum of the intensities of these light sources. In the situation of FIG. 2A, light sources 140b, 140d and 140f may be inactive in the sense that they do not emit light. In a more general case, up to all of the light sources may be used to generate a color in the angular aspect 100a, and the intensity of the light sources is determined by the weight of the linear combination of the combinations used. For example, light sources 140b, 140d and 140f may be present in combinations with only low weights, corresponding to low intensity levels.

[0029] Turning now to FIG. 2B, light sources 140b, 140d, and 140f are used to generate a particular color in angular plane 100b of light field 100, the same color as in FIG. 2A. Part 100b is in a different angular portion of the light field than where part 100a is. The particular color is determined by the relative intensities of light sources 140b, 140d, and 140f, and the brightness of the color is determined by the sum of the intensities of these light sources. In the situation of FIG. 2B, light sources 140a, 140c, and 140e may be inactive in the sense that they do not emit light. Again, in the more general case, up to all of the light sources may be used to generate the color in angular plane 100b, and the intensity of the light sources is determined by the weight of the linear combination of the combinations used. For example, light sources 140a, 140c, and 140e may be present in combinations with only low weights corresponding to low intensity levels. In some embodiments, angular planes 100a and 100b may correspond to different pixels of an image. A user may perceive a particular color on angled surfaces 100a and 100b as the same color.

[0030] The angular faces 100a and 100b of the light field 100 may be associated with different propagation characteristics for the light in the waveguide 110, so that light sources may be selectively used for portions that are sufficiently suited to the respective propagation characteristics to produce a desired visual effect for the user, taking into account the location and / or angle dependency of the propagation characteristics. In some embodiments, the light field 100 is divided into two or more sections, such that a particular subset of the available light sources, and thus potentially the available wavelengths, is used for each section. In general, the number of defined sections of the light field 100 may be equal to the number of defined combinations of light sources. The same color may thus be created using multiple combinations of light sources, depending on where the color is created in the light field 100 and, consequently, in the image of the waveguide display.

[0031] When encoding still or video images in the light field 100, the angular range of the light field 100 may be scanned continuously, such that different angular planes of the light field 100 are scanned using different combinations of light sources during successive scans. By continuous scanning, we mean herein an iterative process in which color elements are created throughout the angular range of the light field 100 in motion. In some embodiments, the light sources can be individually configured for a larger image area, rather than for each pixel. In some embodiments, the light sources can be individually configured for each pixel without scanning. The principles disclosed herein are useful even in embodiments in which scanning is not performed.

[0032] Although illustrated with six light sources 114, already four light sources make it possible to define three combinations of three or four light sources out of four total light sources. Some colors may be reproducible with one or two light sources depending on the color and spectrum of the light sources. For example, if there are four total light sources, each generating distinct wavelengths A, B, C and D, this allows to build subsets ABC, ABD, BCD and ACD. Each one of the subsets can be used for mixing to create different visible colors. Instead of switching off, a light source may be configured to act on a particular pixel with a lower intensity, for example 5% of its maximum intensity. Waveguide-based color displays may be configured to reproduce more or less all of the colors that humans can see, or in some embodiments, a subset of the colors that the human eye can recognize may suffice. In some embodiments, a monochrome display may suffice. For example, for movie viewing, a wide range of colors is required, while the display of instrument panels in a car or aircraft may be made with a more limited set of colors. More generally, weighted linear combinations of light sources may be used to create multiple colors or even just one color, so that multiple combinations may be used to create a single color. In some embodiments, all colors used may be created using multiple combinations of light sources. The light sources may be monochromatic, narrowband, broadband, or have multiple spectral peaks, so long as they can be mixed to produce the desired range of colors.

[0033] One approach to generating pixel / angle dependent distributions in non-scanning systems is to synchronize the light source using a micromirror display, which is a liquid-crystal on silicon (LCOS) display that can be configured to set pixels to a reflective state or to be off. Typically in these systems, color is realized by setting pixels on and off in rapid succession in synchronization with the activation times of red, green, and blue light sources. This also holds true for larger numbers of light sources.

[0034] FIG. 3 illustrates an example device capable of supporting at least some embodiments of the present invention. An apparatus 300 is illustrated, which may include a control mechanism for operating an arrangement such as that illustrated in FIG. 1 or FIG. 2. The apparatus 300 includes a processor 310, which may include, for example, a single or multi-core processor or a microcontroller, where a single-core processor includes one processing core and a multi-core processor includes multiple processing cores. The processor 310 may generally include a controller. The processor 310 may include multiple processors. The processor 310 may be a controller. The processing core may include, for example, a Cortex-A8 processing core manufactured by ARM Holdings, Inc., or a Steamroller processing core designed by Advanced Micro Devices Corporation. The processor 310 may include at least one Qualcomm Snapdragon and / or Intel Atom processor. The processor 310 may include at least one application-specific integrated circuit (ASIC). The processor 310 may comprise at least one field-programmable gate array (FPGA). The processor 310 may be a means for performing steps of the methods in the apparatus 300, such as generating, receiving, and transmitting. The processor 310 may be configured to perform operations at least in part by computer instructions.

[0035] The device 300 may comprise a memory 320. The memory 320 may include random access memory and / or permanent memory. The memory 320 may comprise at least one RAM chip. The memory 320 may include, for example, solid state memory, magnetic memory, optical memory, and / or holographic memory. The memory 320 may be at least partially accessible to the processor 310. The memory 320 may be at least partially comprised in the processor 310. The memory 320 may be a means for storing information. The memory 320 may comprise computer instructions that the processor 310 is configured to execute. The processor 310 and / or at least one of its processing cores may be considered to be configured to execute a particular operation when computer instructions configured to cause the processor 310 to perform said particular operation are stored in the memory 320 and the entire device 300 is configured to operate under the direction of the processor 310 using the computer instructions from the memory 320. The memory 320 may be at least partially comprised in the processor 310. The memory 320 may be, at least in part, external to the device 300, but accessible to the device 300. The memory 320 may store, for example, information defining the segments of the light field 100.

[0036] The apparatus 300 may comprise a transmitter 330. The apparatus 300 may comprise a receiver 340. The transmitter 330 and the receiver 340 may be configured to transmit and receive information, respectively, according to at least one cellular or non-cellular standard. The transmitter 330 may comprise multiple transmitters. The receiver 340 may comprise multiple receivers. The receiver 340 may be configured to receive an input image, and the transmitter 330 may be configured to output control commands to, for example, orient the mirror 130, if present, and the light source 140, according to the input image.

[0037] The device 300 may include a user interface (UI) 360. The UI 360 may include at least one of a display, a keyboard, a touch screen, a vibrator arranged to signal a user by vibrating the device 300, a speaker, and a microphone. A user may be able to operate the device 300 via the UI 360, for example, to set display parameters.

[0038] The processor 310 may be equipped with a transmitter arranged to output information from the processor 310 to other devices included in the device 300 via electrical leads within the device 300. Such a transmitter may, for example, include a serial bus transmitter arranged to output information via at least one electrical lead to the memory 320 for storage in the memory 320. Instead of a serial bus, the transmitter may include a parallel bus transmitter. Similarly, the processor 310 may be equipped with a receiver arranged to receive information at the processor 310 from other devices included in the device 300 via electrical leads within the device 300. Such a receiver may, for example, include a serial bus receiver arranged to receive information via at least one electrical lead from the receiver 340 for processing in the processor 310. Instead of a serial bus, the receiver may include a parallel bus receiver.

[0039] The device 300 may include additional devices not illustrated in FIG 3. In some embodiments, the device 300 does not include at least one of the devices described above. For example, the device 300 may not include the user interface 360.

[0040] The processor 310, memory 320, transmitter 330, receiver 340, NFC transceiver 350, UI 360 and / or user identification module 370 may be interconnected by electrical leads within device 300 in a number of different ways. For example, each of the aforementioned devices may be individually connected to a master bus within device 300, allowing the devices to exchange information. However, as will be appreciated by those skilled in the art, this is only one example and depending on the embodiment, various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the present invention.

[0041] 4 is a flow chart of a method according to at least some embodiments of the invention. The illustrated method steps may be in a waveguide-based display, a light guide arrangement in or for a waveguide-based display, or a control mechanism configured to control its functionality when incorporated therein.

[0042] Step 410 includes using an optical system to generate a configurable image encoded in the light field. Step 420 includes receiving light from the light field into at least one light guide and transmitting the light to multiple locations in each of the at least one light guide for emission to create a waveguide-based display. Finally, in step 430, the optical system includes a set of light sources, each of at least four light sources configured to generate light of distinct spectral characteristics in the visible spectrum, and the method includes using two different combinations of light sources to generate the same color in two angular planes of the light field. The transmission can be by a light guide such that the light is transmitted inside the light guide.

[0043] It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures, process steps, or materials disclosed herein, but rather to equivalents thereof that would be recognized by one of ordinary skill in the relevant arts. It is also to be understood that the terminology employed herein is used only for the purpose of describing particular embodiments, and is not intended to be limiting.

[0044] Reference throughout this specification to an embodiment or examples means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment. When a numerical value is referred to using a term, such as about or substantially, the exact numerical value is also disclosed.

[0045] As used herein, a plurality of articles, structural elements, components, and / or materials may be presented in a common enumeration for convenience. However, these enumerations should be construed as if each element of the enumeration were individually identified as a separate and unique element. Thus, any individual element of such enumeration should not be construed as being effectively equivalent to other elements of the same enumeration solely based on their presentation in a common group, unless indicated to the contrary. In addition, various embodiments and examples of the invention may be referred to herein, along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives should not be construed as being effectively equivalent to each other, but should be considered as separate and independent manifestations of the invention.

[0046] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the foregoing description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the present invention. However, one of ordinary skill in the relevant art will recognize that the present invention may be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the present invention.

[0047] While the foregoing examples illustrate the principles of the present invention in one or more specific applications, it will be apparent to those skilled in the art that numerous modifications in the embodiments, usage and details may be made without the exercise of inventive skill and without departing from the principles and concepts of the present invention. Accordingly, it is not intended that the present invention be limited except as by the claims set forth below.

[0048] The verbs "comprise" and "include" are used in this document as open limitations that do not exclude or require the presence of further unrecited features. Features recited in the dependent claims are mutually freely combinable, unless expressly stated otherwise. Furthermore, it is to be understood that the use of "a" or "an", i.e. the singular, throughout this document does not exclude a plurality. [Industrial Applicability]

[0049] At least some embodiments of the present invention find industrial application in improving waveguide displays. [Explanation of symbols]

[0050] LCOS Liquid Crystal on Silicon LED Light Emitting Diode MEMS Microelectromechanical 100 Light Field 102 Light Guide 104 light 110 Waveguide 112a, 112 element 114 Directed Light 120 eyes 130 Mirror 140 light source 140a, 140b, 140c, 140d, 140e, 140f light source 100a, 100b Parts of the light field 100 300~360 Structure of the equipment in Figure 3 410-430 Steps of the method of FIG.

Claims

1. 1. An optical waveguide arrangement, comprising: an optical system configured to generate a configurable image encoded in a light field; at least one light guide arranged to receive light from said light field and to transmit said light to a plurality of locations in said light guide for emission, creating a waveguide-based display; and Equipped with the optical system comprises a set of at least three light sources, each one of which is configured to generate light of distinct spectral characteristics in the visible spectrum, and the optical system is configured to use two different weighted combinations of the same set of light sources to generate the same color in two angular planes of the light field; Optical waveguide arrangement.

2. The light guide arrangement of claim 1 , wherein the optical system comprises at least four light sources.

3. The light guide arrangement of claim 1 , wherein the optical system comprises at least four light sources, the optical system configured to generate a full color image encoded in the light field.

4. 3. The optical waveguide arrangement of claim 1 or claim 2, wherein said generating each distinct spectral characteristic comprises generating light output having at least one distinct spectral peak.

5. 3. The light guide arrangement of claim 1 or claim 2, wherein the configurable image comprises a moving image.

6. 3. The optical waveguide arrangement of claim 1 or claim 2, wherein the at least four light sources include laser light sources.

7. 3. The light guide arrangement of claim 1 or claim 2, wherein the at least four light sources comprise light emitting diode light sources.

8. 3. The light guide arrangement of claim 1 or claim 2, wherein the light guide arrangement is configured to provide the waveguide-based display as a head-mounted display.

9. - generating a configurable image encoded in a light field using an optical system; receiving light from said light field into at least one light guide and transmitting said light to a plurality of locations in said light guide for emission to create a waveguide-based display; A method comprising: the optical system comprises a set of at least three light sources, each of which is configured to generate light of distinct spectral characteristics in the visible spectrum, and the method comprises using two different weighted combinations of the same set of light sources to generate the same color in two angular planes of the light field; method.

10. The method of claim 9 , wherein the optical system comprises at least four light sources.

11. 10. The method of claim 9, wherein the optical system comprises four light sources, and the method includes generating a full color image encoded in the light field.

12. 11. The method of claim 9 or claim 10, wherein said generating each distinct spectral characteristic comprises generating light that is output with at least one distinct spectral peak.

13. The method of claim 9 or claim 10, wherein the configurable image comprises a moving image.

14. 11. The method of claim 9 or claim 10, wherein the at least four light sources include laser light sources.

15. 11. The method of claim 9 or claim 10, wherein the at least four light sources comprise light emitting diode light sources.

16. 11. The method of claim 9 or claim 10, comprising providing the waveguide-based display as a head-mounted display.

17. - using an optical system to generate a configurable image encoded in a light field; - receiving light from said light field into at least one light guide and transmitting said light in said light guide to a plurality of locations for emission, creating a waveguide-based display; 1. An apparatus comprising means for: - an apparatus wherein the optical system comprises a set of at least three light sources, each of the light sources configured to produce light of distinct spectral characteristics in the visible spectrum, and the optical system is configured to use two different weighted combinations of the same set of light sources to produce the same color in two angular planes of the light field.

18. When executed by at least one processor, the device performs at least: - using an optical system to generate a configurable image encoded in a light field; receiving light from said light field into at least one light guide and transmitting said light in said light guide to a plurality of locations for emission, thereby creating a waveguide-based display; A non-transitory computer-readable medium having stored thereon a set of computer-readable instructions, comprising: a non-transitory computer readable medium, wherein the optical system comprises a set of at least three light sources, each of the light sources configured to generate light of distinct spectral characteristics in the visible spectrum, and the set of computer readable instructions is configured to use the optical system to generate the same color in two angular planes of the light field using two different weighted combinations of the same set of light sources.

19. A computer program configured to cause the computer to carry out the method of claim 9 or 10.

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