WO2020205269A1 - Method and apparatus for a variable-resolution screen - Google Patents
Method and apparatus for a variable-resolution screen Download PDFInfo
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- WO2020205269A1 WO2020205269A1 PCT/US2020/023695 US2020023695W WO2020205269A1 WO 2020205269 A1 WO2020205269 A1 WO 2020205269A1 US 2020023695 W US2020023695 W US 2020023695W WO 2020205269 A1 WO2020205269 A1 WO 2020205269A1
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3179—Video signal processing therefor
- H04N9/3188—Scale or resolution adjustment
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/0006—Arrays
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/26—Projecting separately subsidiary matter simultaneously with main image
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3141—Constructional details thereof
- H04N9/3147—Multi-projection systems
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
- G02B2027/011—Head-up displays characterised by optical features comprising device for correcting geometrical aberrations, distortion
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/10—Scanning systems
- G02B26/101—Scanning systems with both horizontal and vertical deflecting means, e.g. raster or XY scanners
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
Definitions
- the systems, apparatuses and methods described herein generally relate to video projection systems and, in particular, to video projection systems for near-eye displays, such as in virtual reality headsets.
- FIG. 1A shows the single pixel 101 approach to display devices such as LCD (Liquid crystal display) or OLED (Organic light-emitting diode) computer or television displays.
- Figure IB shows the scanline approach 102 used in other display devices such as CRT (Cathode-ray tube) computer or television displays and CRT or LBS (Laser beam steering) video projectors.
- CRT Cathode-ray tube
- LBS Laser beam steering
- variable-resolution screens 103 has emerged because of increasing manufacturing costs of high resolution microdisplays, displays and projectors and much more demanding computational, bandwidth and storage requirements for display content created for traditional screens due to their increasing resolutions and fields of view, especially in virtual reality, augmented reality and mixed reality headsets (from now on referred to as“XR headsets”).
- Current XR headsets aim to provide a field of view close to the human field of view, which is on average 270 degrees horizontally by 135 degrees vertically taking into account eye rotations and is usually lower than that, for example 90 degrees horizontally by 100 degrees vertically for virtual reality headsets and lower than 50 degrees horizontally by 50 degrees vertically for augmented reality headsets which is still higher than many screens at normal viewing distances such as monitors, TVs and projection screens.
- video projectors that can be set up to project very wide and cover more of the viewer’s field of view than with display technologies such as CRT, LCD, OLED or microLED monitors and TVs and projection screens at normal viewing distances.
- HMPDs Head-Mounted Projective Display
- HMPDs Head-Mounted Projective Display
- tilting beam splitters or steering an image with mirrors or prisms to reposition the high resolution area is challenging and results in perspective distortion and some optical aberrations which some of the methods described herein solve.
- tilting or rotating mechanical parts have disadvantages associated with mechanically moving parts which some of the methods described herein solve.
- An optical apparatus for creating a variable-resolution image stream on a screen is described herein that is made up of a projector connected to a video source, where the projector transmits a light image stream in the form of a high resolution, small image component and a low resolution, large image component.
- Each frame of the variable-resolution image stream may be or include one of a) a low resolution, large image, b) a high resolution, small image, or a superimposition of a high resolution, small image and a low resolution, large image.
- This light image stream is sent to an image steering element that directs the high resolution, small image component and the low resolution, large image component to a small image optical element and to a large image optical element.
- the image steering element may function as an image separation element, and may separate the first image component from the second image component in embodiments.
- the optical apparatus may also include an image separation element that separates the high resolution, small image component and the low resolution, large image component into a high resolution, small image stream and a low resolution, large image stream, where the small image optical element and the large image optical element focus the low resolution, large image stream and the high resolution, small image stream on the screen such that the low resolution, large image stream and the high resolution, small image stream appear as the variable-resolution image stream on the screen.
- the light image stream from the projector is time multiplexed between the high resolution, small image component in a first frame (frame n) and the low resolution, large image component in a next frame (frame n+1).
- the image separation element could be an optical shutter to manage the time multiplexing.
- the light image stream from the projector could have the high resolution, small image component on one part of each image and a low resolution, large image component on another part of the image.
- the image separation element could be an optical mask (stencil) to support this embodiment.
- the screen is embedded in a virtual reality headset.
- the small image optical element could include a lens array.
- the image steering element could be a rotating optical slab, mirrors, beam splitter (e.g., polarizer beam splitter or reflective polarizer beam splitter), wedge (Risley) prisms, liquid crystal switchable mirrors, optical shutters or optical masking elements.
- the large image optical element could be a lens or other optics that focuses the low resolution, large image stream to an outer portion of the screen or viewer’s field of view.
- the small image optical element could be a lens or other optics that focuses the high resolution, small image stream to a center portion of the screen or viewer’s field of view.
- An optical method creating a variable-resolution image stream on a screen includes the steps of creating a light image stream in the form of a high resolution, small image component and a low resolution, large image component with a projector connected to a video source; directing the high resolution, small image component and the low resolution, large image component, with an image or beam steering element, to a small image optical element and to a large image optical element; separating the high resolution, small image component and the low resolution, large image component into a high resolution, small image stream and a low resolution, large image stream with an image separation element; and focusing, by the small image optical element and the large image optical element, the low resolution, large image stream and the high resolution, small image stream to form the variable-resolution image stream on the screen.
- the light image stream from the projector is time multiplexed between the high resolution, small image component in a first frame (frame n) and the low resolution, large image component in a second frame (frame n+1).
- the separation of these components could be accomplished by using an optical shutter for the image separation element.
- the light image stream from the projector could have the high resolution, small image component on one part of each image and a low resolution, large image component on another part of the image, and the image separation element could be an optical mask (stencil).
- the screen is embedded in a virtual reality headset.
- the small image optical element could include a lens array.
- the image steering element could be a rotating optical slab, mirrors, beam splitter, wedge (Risley) prisms, optical shutters, liquid crystal switchable mirrors, or optical masking elements.
- the large image optical element could be a lens or other optics that focuses the low resolution, large image stream to an outer portion of the screen or viewer’s field of view.
- the small image optical element could be a lens or other optics that focuses the high resolution, small image stream to a center portion of the screen or viewer’s field of view.
- the screen could be a flat or curved diffuse projection screen, a flat or curved retroreflective projection screen, a flat or curved holographic diffuser projection screen, a flat or curved fiber optic taper bonded to a first surface or projection screen, or a flat or curved mirror or Fresnel mirror which focuses a projection onto a viewer's retina (such as the ones used in collimated display systems).
- the screen could also be a viewer’s retina.
- the projector could be a microdisplay or a display.
- An optical apparatus comprising: an image source configured to output a first image component and a second image component; and one or more optical element configured to: receive the first image component and output a high resolution, small image focused onto a screen; and receive the second image component and output a low resolution, large image focused onto the screen; wherein the high resolution, small image and the low resolution, large image appear as a variable resolution image on the screen.
- the one or more optical element comprises: a small image optical element configured to receive the first image component and output the high resolution, small image focused onto a screen; and a large image optical element configured to receive the second image component and output the low
- optical apparatus of example 3 further comprising: an image steering element to direct the first image component to the small image optical element and to direct the second image component to the large image optical element.
- optical apparatus of example 3 wherein the small image optical element includes a duplication element and an optical masking element.
- optical masking element is slightly offset from an intermediate image plane to reduce a screen-door effect from the optical masking element.
- optical masking element is further to display a copy of the high resolution, small image, wherein a single duplicate of the high resolution, small image merges with the copy of the high resolution, small image to provide at least one of an increased contrast or an increased color depth for the high resolution, small image.
- the duplication element is to receive the high resolution, small image and output a plurality of duplicates of the high resolution, small image
- the optical masking element is to mask off one or more of the plurality of duplicates of the high resolution, small image such that portions of one or more duplicates of the high resolution, small image remain, wherein the portions of the one or more duplicates of the high resolution, small image together form a complete single duplicate of the high resolution, small image that is focused onto a target position on the screen.
- the portions of the one or more duplicates of the high resolution, small image comprise digitally rearranged portions of at least four duplicates of the high resolution, small image, and wherein the optical masking element is configured to reconstruct the complete single duplicate of the high resolution, small image from the digitally rearranged portions of the at least four duplicates of the high resolution, small image.
- the one or more optical element includes a masking element, wherein the masking element is to display a copy of the low resolution, large image, and wherein the low resolution, large image merges with the copy of the low resolution, large image to provide at least one of an increased contrast or an increased color depth for the low resolution, large image.
- the image source is configured to output an initial image comprising the first image component and the second image component, wherein the first image component comprises a first plurality of pixels of the initial image and the second image component comprises a second plurality of pixels of the initial image.
- the one or more optical element includes one or more electrically tunable lens or mirror, and wherein the electrically tunable lens or mirror functions as a zoom lens or mirror for controlling a size of at least one of the high resolution, small image or the low resolution, large image on the screen.
- the one or more optical element includes one or more electrically tunable lens or mirror, and wherein the one or more electrically tunable lens or mirror functions as a focusing lens or mirror for controlling a focus of at least one of the high resolution, small image or the low resolution, large image on the screen.
- optical apparatus of example 1 further comprising a rotating optical slab to steer an image stream comprising the high resolution, small image output from the small image optical element.
- the image source comprises a laser beam steering (LBS) projector, wherein the first image component is a narrow beam produced by the LBS projector, and wherein the second image component is a wide beam produced by the LBS projector.
- LBS laser beam steering
- optical apparatus of example 1 further comprising: a gaze tracking element to detect a foveal view of a viewer; wherein a position of the high resolution, small image or a single duplicate of the high resolution, small image corresponds to the foveal view of the viewer.
- An optical apparatus comprising: a first image source configured to output a low resolution, large image; a second image source configured to output a high resolution, small image; an image duplication element to receive the high resolution, small image and output a plurality of duplicates of the high resolution, small image; and an optical masking element to mask off one or more of the plurality of duplicates of the high resolution, small image such that portions of one or more duplicates of the high resolution, small image remain, wherein the portions of the one or more duplicates of the high resolution, small image together form a complete single duplicate of the high resolution, small image that is focused onto a target position on a screen; wherein the single duplicate of the high resolution, small image and the low resolution, large image appear as a variable resolution image on the screen.
- at least one of the first image source or the second image source comprises at least one of a projector, a display or a microdisplay.
- optical apparatus of example 21 further comprising: one or more electrically tunable lens or mirror, wherein the one or more electrically tunable lens or mirror functions as focusing lens or mirror for controlling a focus of at least one of the high resolution, small image, the single duplicate of the high resolution, small image or the low resolution, large image on the screen.
- optical masking element is further to display a copy of the high resolution, small image, wherein a single duplicate of the high resolution, small image merges with the copy of the high resolution, small image to provide at least one of an increased contrast or an increased color depth for the single duplicate of the high resolution, small image.
- optical masking element is further to display a copy of the low resolution, large image, wherein the low resolution, large image merges with the copy of the low resolution, large image to provide at least one of an increased contrast or an increased color depth for the low resolution, large image.
- optical apparatus of example 21 further comprising: a gaze tracking element to detect a foveal view of a viewer; wherein a position of the single duplicate of the high resolution, small image corresponds to the foveal view of the viewer.
- An optical apparatus comprising: an image source configured to output a first image component and a second image component; an image steering element configured to direct the first image component to a small image optical element and to direct the second image component to a large image optical element; the small image optical element, configured to receive the first image component and output a plurality of duplicates of a high resolution, small image focused onto an intermediate image plane; the large image optical element, configured to receive the second image component and output a low resolution, large image; and an optical masking element to mask one or more of the plurality of duplicates of the high resolution, small image; wherein a superimposition of the one or more of the plurality of duplicates of the high resolution, small image with the low resolution, large image forms a combined image.
- optical apparatus of example 31 further comprising: a beam combiner to combine the one or more of the plurality of duplicates of the high resolution, small image with the low resolution, large image to produce the combined image.
- optical masking element is between the small image optical element and the beam combiner, and wherein the combined image comprises a single duplicate of the high resolution, small image.
- the optical apparatus further comprising: a second image steering element to: split the combined image into the plurality of duplicates of the high resolution, small image and the low resolution, large image; direct the plurality of duplicates of the high resolution, small image onto a first screen; and direct the low resolution, large image onto a second screen; wherein the optical masking element is between the first screen and the beam splitter, the optical masking element to mask off one or more of the plurality of duplicates of the high resolution, small image such that a single duplicate of the high resolution, small image reaches the first screen; and wherein the single duplicate of the high resolution, small image and the low resolution, large image are to recombine to produce a variable resolution image.
- a second image steering element to: split the combined image into the plurality of duplicates of the high resolution, small image and the low resolution, large image; direct the plurality of duplicates of the high resolution, small image onto a first screen; and direct the low resolution, large image onto a second screen; wherein the optical masking element is between the first screen and
- optical apparatus of example 31 further comprising: an eyepiece or a waveguide, wherein the combined image is a variable resolution image that is directed to the eyepiece or the waveguide.
- optical apparatus of example 41, wherein the image source comprises a separate display or microdisplay panel for each color channel of a plurality of color channels, the optical apparatus further comprising: at least one of a trichroic prism, an X-cube prism or a dichroic filter to optically combine the plurality of color channels.
- optical apparatus of example 31 further comprising: a gaze tracking element to detect a foveal view of a viewer; wherein a single duplicate of the high resolution, small image is to be positioned on the low resolution, large image at a position corresponding to the foveal view of the viewer.
- optical masking element is further to display a copy of the high resolution, small image, wherein a single duplicate of the high resolution, small image merges with the copy of the high resolution, small image to provide at least one of an increased contrast or an increased color depth for the high resolution, small image.
- optical masking element is to mask the one or more of the plurality of duplicates of the high resolution, small image such that a single duplicate of the high resolution, small image remains.
- An optical apparatus comprising: a first image source configured to output a high resolution, small image; a small image optical element, configured to receive the high resolution, small image and output a plurality of duplicates of the high resolution, small image; an image steering element to direct the plurality of duplicates of the high resolution, small image onto a screen; an optical masking element to mask off one or more of the plurality of duplicates of the high resolution, small image such that a single duplicate of the high resolution, small image remains; and a second image source configured to output a low resolution, large image; wherein the single duplicate of the high resolution, small image is to combine with the low resolution, large image to produce a variable resolution image.
- the image steering element comprises a beam splitter, wherein the optical masking element is between the screen and the beam splitter, wherein the single duplicate of the high resolution, small image is directed to the beam splitter, and wherein the beam splitter is to combine the single duplicate of the high resolution, small image with the low resolution, large image to produce the variable resolution image.
- variable resolution image is focused onto an eye of a viewer.
- the image source comprises a separate display or microdisplay panel for each color channel of a plurality of color channels, the optical apparatus further comprising: at least one of a trichroic prism, an X-cube prism or a dichroic filter to optically combine the plurality of color channels.
- optical apparatus of example 47 further comprising: a gaze tracking element to detect a foveal view of a viewer; wherein the single duplicate of the high resolution, small image is positioned on the low resolution, large image at a position corresponding to the foveal view of the viewer.
- optical masking element is a display or microdisplay that comprises at least one of pixels or subpixels and gaps between at least one of the pixels or the subpixels, and wherein the display or microdisplay is offset from the intermediate image plane.
- optical masking element is further to display a copy of the high resolution, small image, wherein the single duplicate of the high resolution, small image merges with the copy of the high resolution, small image to provide at least one of an increased contrast or an increased color depth for the high resolution, small image.
- optical apparatus of example 47 further comprising: an eyepiece or a waveguide, wherein the variable resolution image is directed to the eyepiece or the waveguide.
- An optical apparatus comprising: an image source configured to output a first image component and a second image component; an image steering element configured to direct the first image component to a small image optical element and to direct the second image component to a large image optical element; the small image optical element, configured to receive the first image component and output a high resolution, small image focused onto a screen; and the large image optical element, configured to receive the second image component and output a low resolution, large image focused onto the screen; wherein the high resolution, small image and the low resolution, large image appear as a variable resolution image on the screen.
- optical apparatus of example 61 further comprising: an image separation element that separates the first image component from the second image component, wherein the image separation element comprises an optical mask.
- optical apparatus of example 67 further comprising: an optical masking element to mask off at least portions of one or more of the plurality of duplicates of the high resolution, small image.
- optical apparatus of example 68 wherein the optical masking element comprises a display, and wherein the lens array is configured to focus the plurality of duplicates of the high resolution, small image onto pixels of the display, the optical apparatus further comprising: a second lens array or lens to focus a single duplicate of the high resolution, small image onto the screen.
- optical apparatus of example 68, wherein the optical masking element comprises a microdisplay, and wherein the lens array is configured to focus the plurality of duplicates of the high resolution, small image onto pixels of the microdisplay, the optical apparatus further comprising: a second lens array or lens to focus a single duplicate of the high resolution, small image onto the screen.
- optical masking element is configured to reconstruct a single duplicate of the high resolution, small image from digitally rearranged portions of at least four duplicates of the high resolution, small image.
- optical apparatus of example 61 further comprising: a second image steering element to control a placement of the high resolution, small image on the screen.
- the large image optical element comprises at least one lens configured to focus the low resolution, large image onto a field of view of a viewer
- the small image optical element comprises at least one lens configured to focus the high resolution, small image onto an inner portion of the field of view of the viewer.
- optical apparatus of example 61 further comprising:
- an image separation element that separates the first image component from the second image component, wherein the image separation element comprises an optical shutter.
- the optical apparatus of example 61 further comprising: a mask to mask a portion of the low resolution, large image that overlaps with the high resolution, small image.
- a gaze tracking element to detect a foveal view of a viewer; wherein the high resolution, small image is positioned on the low resolution, large image at a position corresponding to the foveal view of the viewer.
- optical apparatus of example 61 further comprising: a beam combiner to combine the high resolution, small image and the low resolution, large image to produce the variable resolution image for output onto the screen.
- An optical apparatus comprising: a first image source configured to output a low resolution, large image focused onto a screen; a second image source configured to output a high resolution, small image; an image duplication element to receive the high resolution, small image and output a plurality of duplicates of the high resolution, small image; and an optical masking element to mask off one or more of the plurality of duplicates of the high resolution, small image such that portions of one or more duplicates of the high resolution, small image remain, wherein the portions of the one or more duplicates of the high resolution, small image together form a complete single duplicate of the high resolution, small image that is focused onto a target position on the screen; wherein the high resolution, small image and the low resolution, large image appear as a variable resolution image on the screen.
- optical apparatus comprising a display, and wherein the lens array is configured to focus the plurality of duplicates of the high resolution, small image onto pixels of the display, the optical apparatus further comprising: a second lens array or lens to focus the single duplicate of the high resolution, small image onto the screen.
- optical apparatus comprising a microdisplay, and wherein the lens array is configured to focus the plurality of duplicates of the high resolution, small image onto pixels of the microdisplay, the optical apparatus further comprising: a second lens array or lens to focus the single duplicate of the high resolution, small image onto the screen.
- optical apparatus of example 81 further comprising: a gaze tracking element to detect a foveal view of a viewer; wherein the single duplicate of the high resolution, small image is positioned on the low resolution, large image at a position corresponding to the foveal view of the viewer.
- optical apparatus of example 81 further comprising: a beam combiner to combine the high resolution, small image with the low resolution, large image to produce the variable resolution image for output onto the screen.
- An optical apparatus for creating a variable-resolution image stream on a screen comprising: a projector connected to a video source, where the projector transmits a light image stream in the form of a high resolution, small image component and a low resolution, large image component; an image steering element that directs the high resolution, small image component and the low resolution, large image component to a small image optical element and to a large image optical element; and an image separation element that separates the high resolution, small image component and the low resolution, large image component into a high resolution, small image stream and a low resolution, large image stream; where the small image optical element and the large image optical element focus the low resolution, large image stream and the high resolution, small image stream on the screen such that the low resolution, large image stream and the high resolution, small image stream appear as the variable-resolution image stream on the screen.
- An optical method for creating a variable-resolution image stream on a screen comprising: creating a light image stream in the form of a high resolution, small image component and a low resolution, large image component with a projector connected to a video source; directing the high resolution, small image component and the low resolution, large image component, with an image steering element, to a small image optical element and to a large image optical element; separating the high resolution, small image component and the low resolution, large image component into a high resolution, small image stream and a low resolution, large image stream with an image separation element; and focusing, by the small image optical element and the large image optical element, the low resolution, large image stream and the high resolution, small image stream to form the variable-resolution image stream on the screen.
- 107 The method of example 106 wherein the light image stream from the projector is time multiplexed between the high resolution, small image component in a first frame and the low resolution, large image component in a second frame.
- Figure 1 A shows the single pixel approach to display devices.
- Figure IB shows the scanline approach to display devices.
- Figure 1C shows a multi-focus approach to a display.
- Figure 2 illustrates using persistence of vision to blend images from two consecutive frames into one final image.
- Figure 3 shows splitting an image of a microdisplay, display or projector into two parts that are combined.
- Figure 4A is a functional flow of the light through the optical functions in the simplest embodiment.
- Figure 4B is a hardware flow of the light through the optical elements in the simplest embodiment.
- Figure 5A is a functional flow of the light through the optical functions in a slightly more complex embodiment.
- Figure 5B is a hardware flow of the light through the optical elements in a slightly more complex embodiment.
- Figure 5C is a hardware flow of the light through the optical elements as in the previous drawing with an optical mask (stencil).
- Figure 5D is a hardware flow of the light through the optical elements as in the
- Figure 5B for each eye in a head-mounted display.
- Figure 5E illustrates an embodiment using optical slab elements.
- Figure 5F is a hardware flow of the light through the optical elements in a slightly more complex embodiment, using a screen.
- Figure 5G is a hardware flow of the light through the optical elements as in the previous drawing with an optical mask, using a screen.
- Figure 5H is a hardware flow of the light through the optical elements as in the
- Figure 6A shows an illustration with rectangles representing individual pixels.
- Figure 6B shows an illustration with individual pixels displaying an actual image.
- Figure 7A shows an original image.
- Figure 7B shows a perspective distorted image.
- Figure 8A shows the image with no distortion or distortion mismatch corrected.
- Figure 8B shows the image with the distortion mismatch.
- Figure 9A shows light going through an optical slab.
- Figure 9B shows light going through an optical slab at an angle.
- Figure 9C shows light going through an optical slab at a different angle.
- Figure 9D shows a superimposition of light going through the same optical slab at two opposite maximum angles.
- Figure 10A illustrates offsetting the image or beam with two mirrors tilted 45 degrees.
- Figure 10B illustrates offsetting the image or beam with two mirrors tilted 40 degrees.
- Figure 11 illustrates offsetting the image or beam with a set of four mirrors.
- Figure 12 illustrates offsetting the image or beam with a set of Dove prism and four mirrors.
- Figure 13 shows a functional flow of light through the optical functions in a lens array embodiment.
- Figure 14 shows a functional flow of light through the optical functions in a second lens array embodiment.
- Figure 15 shows the light flow through the elements of one lens array embodiment.
- Figures 16A and 16B illustrates an image (Figure 16A) as it is seen on a screen or viewer’s retina ( Figure 16B) after using a lens array.
- Figure 17A shows an embodiment using a matched set of lens arrays and an optical masking element.
- Figure 17B demonstrates reflective microdisplay used for the optical masking element.
- Figure 17C shows the use of a display, such as an LCD display with its reflective and backlight layers removed as the optical masking element.
- Figure 17D illustrates the elements for generating an image with large and small parts that are already optically combined, with the ability to hide the duplicated images of the small part and show one of them.
- Figure 17E shows the elements for generating an image with large and small parts that are already optically combined, with the ability to hide the duplicated images of the small part and show one of them.
- Figure 17F demonstrates the elements for another embodiments for generating an image with large and small parts that are already optically combined, with the ability to hide the duplicated images of the small part and show one of them.
- Figure 17G presents another embodiments of the elements for generating an image with large and small parts that are already optically combined, with the ability to hide the duplicated images of the small part and show one of them.
- Figure 18 illustrates digitally and optically rearranging portions of an image.
- Figure 19 shows the portions of the images to be optically and digitally rearranged do not have to be partitioned from the middle of the images.
- Figure 20 shows an embodiment of the mounting of the present inventions in a head-mounted display were the physical size is reduced.
- Figure 21 shows an embodiment of the mounting of the present inventions in a head-mounted display using a mirror to reduce the physical size of the unit.
- Figure 22 shows an embodiment of the mounting of the present inventions in a head-mounted display using a mirror and a beam splitter to reduce the physical size of the unit.
- Figure 23 illustrates an embodiment that uses a combination of a first optical source that outputs an image onto a screen to show a first portion of a variable resolution image and second optical source to show a second portion of the variable resolution image.
- Figure 24A illustrates a source image, in accordance with an embodiment.
- Figure 24B illustrates the source image of Figure 24A on an optical masking element that is on an intermediate image plane, in accordance with an embodiment.
- Figure 24C illustrates the source image of Figure 24A on an optical masking element that is slightly offset from the intermediate image plane, in accordance with an embodiment.
- Figure 25 shows how spatially modulating an image twice or spatially modulating two images which store different bit depth (color depth) information of an original image, from left to right, produces a higher contrast and/or higher bit depth (color depth) image on the right.
- Figure 26 shows, from left to right, how spatially modulating a high resolution, small image again or spatially modulating a different bit depth (color depth) information of the high resolution, small image on the optical masking element, where it is displayed at a lower resolution, produces a higher contrast and/or higher bit depth (color depth) image on the right.
- the present inventions describe a system and method for implementing a variable-resolution screen, where the area in front of the viewer’s field of view, where the foveal vision expects the greatest resolution, are in a higher resolution than the areas of the screen on the periphery, where the peripheral vision expects less resolution and clarity.
- the area in front of the viewer’s field of view where the foveal vision expects the greatest resolution
- the areas of the screen on the periphery where the peripheral vision expects less resolution and clarity.
- variable-resolution screen which can be defined as a screen which allows the image, when viewed directly or by, but not limited to, an eyepiece (the lens closest to the viewer’s eye) or waveguide, provide a resolution which is not uniform across the image but rather more pixels or scanlines are visible to the viewer where needed on the image, such as the center of the viewer’s field of view and less in other part or parts of the image.
- Such a screen is different from existing screens displaying pre-rendered or real time-rendered foveated content as such methods of variable-resolution content display limit the high resolution part of the content to the native resolution possible with that part of the screen.
- the term“screen” can also be used to describe the viewer’s retina.
- Foveated content is an image, video or real time-generated images where on each image the resolution varies across the image, for example to show more resolution only where the viewer is looking, is able to look at or is meant to look at.
- variable-resolution screen methods and apparatus described here allow to achieve more resolution visible in one or more parts of the image than is possible with the microdisplay, display or projector when used without the methods described here.
- the methods described may be performed using existing computing hardware such as a PC, mobile phone or tablet to provide the pre-rendered or real time-rendered content for it.
- the methods may be performed with as little as a single DLP (Digital light processing), LCoS (Liquid crystal on silicon), LCD (Liquid crystal display), OLED (Organic light-emitting diode), MicroLED or similar microdisplay, display or projector or LBS (Laser beam steering) or similar projector 401, 411, 501, 511, 521, 551, 2301, 5111, 5121, 5151, 1401 for one variable-resolution screen or one of the above for one variable-resolution screen per eye, for example for head-mounted displays.
- display or projector or one per eye allows to minimize the cost of producing such a variable-resolution screen apparatus, reduce weight and size of the apparatus.
- a single microdisplay, display or projector can also refer to microdisplays, displays or projectors where a separate display or microdisplay panel is used for each color channel and they are optically combined such as with a trichroic prism, X-cube prism or dichroic filters. This can be useful for various reasons such as eliminating color separation (also known as“rainbow artifact”) and increasing the refresh rate.
- variable-resolution screens are, but not limited to, virtual reality, augmented reality and mixed reality headsets (“XR headsets”) and video projectors. Positioning with mirrors or wedge prisms of a high resolution small image over a low resolution large image
- a variable-resolution screen can be achieved by positioning a high resolution small image over a low resolution large image with mirrors or wedge (Risley) prisms.
- a single display technology such as a microdisplay or display 401, 411, 501, 511, 521, 551 is operated at fast refresh rates.
- Each consecutive frame (frame n+1) the microdisplay or display is used to either display a small high resolution part 204 or parts of the final image 205 or a large low resolution part 203 or parts of the final image 205 by sharing the refresh rate of the frames 201, 202 and final image 205 between the latter’s two or more parts 203, 204.
- Persistence of vision blends the two parts 203, 204 into one final image 205. See Figure 2.
- the frames alternate with the low resolution frame n 201 displayed followed by high resolution frame n+1 202.
- the eye interprets the two as a single image 205.
- the low resolution portion of the combined screen 203 could have a neutral color (black) in the high resolution area 204.
- the high resolution portion of the combined screen 204 could have a neutral color (black) in the low resolution area 203.
- a slight overlap between the two regions 203, 204 will prevent a noticeable seam or gaps by having a blend region where regions 203, 204 overlap.
- the low resolution section 203 is not masked and blends with the high resolution portion 204 in the area where the high resolution resides.
- a single display technology such as a microdisplay or display is optically split into two or more parts 301, 302. This method allows one part 301 or parts to use more pixels on the final image by sacrificing the resolution of another part 302 or parts on the final image. See Figure 3.
- the two methods can also be combined to allow to create more parts on the final image or to allow to create two or more final images by sharing both the resolution and refresh rate of the microdisplay or display between the parts, such as for using a single microdisplay or display to create final images for both eyes in a head-mounted display.
- FIG. 302 is shown, for example 1920x1080 pixel microdisplay or display split into a small 1080x1080 pixel high resolution part 301 and a large 840x1080 pixel low resolution part 302 (the latter may then be optically flipped 90 degrees for a better aspect ratio).
- the parts 301 and 302 can be resized and superimposed on each other 305.
- the large low resolution part 303 can be masked where the small high resolution part is 304 and where they overlap.
- the masking can further be made more seamless by blending the edges optically or digitally by making the transition less abrupt with a digital resolution falloff in the high resolution small image or dimming the pixels with a falloff on both images.
- the brightness levels between the two parts may be balanced optically such as with neutral density filters or digitally.
- the image of the microdisplay or display is steered with a steering element optomechanically or optically, such as, but not limited to, a rotating mirror or beam splitter 402, 412 and an optional mirror 413, to one of two optical elements 403, 404, 414, 415 for each frame.
- a steering element optomechanically or optically such as, but not limited to, a rotating mirror or beam splitter 402, 412 and an optional mirror 413, to one of two optical elements 403, 404, 414, 415 for each frame.
- image steering elements are a liquid crystal switchable mirror, an optical shutter, a wedge prism, a rotating optical slab, and optical masking elements.
- the image steering element may also function as an image separation element. Alternatively, a separate image separation element may be used in addition to the image steering element.
- image separation elements include optical masking elements, a beam splitter, a optical shutter, a liquid crystal switchable mirror, and so on.
- each image each frame may be blocked or let to pass accordingly before, inside or after the optical element 403, 404, 414, 415 with an optical or mechanical shutter such as an LCD shutter in order to prevent 403, 414 and 404, 415 from receiving the same image of every frame instead of the different images of different consecutive frames.
- a polarizer beam splitter or a reflective polarizer beam splitter is used and the polarization of the image can be controlled each frame before it reaches the beam splitter, such as with a switchable liquid crystal polarization rotator.
- Use of a reflective polarizer beam splitter may provide improved image contrast and/or light throughput as compared to a half-silvered beam splitter or an absorptive-type polarizer beam splitter.
- the image of the microdisplay or display 401, 411 is steered with a steering element such as, but not limited to, a beam splitter, a mirror, or any of the other aforementioned optical steering elements on an image plane 402, 412 and an optional mirror 413, to two optical elements 403, 404, 414, 415.
- a steering element such as, but not limited to, a beam splitter, a mirror, or any of the other aforementioned optical steering elements on an image plane 402, 412 and an optional mirror 413, to two optical elements 403, 404, 414, 415.
- each image is then masked accordingly before, inside or after the optical element 403, 404, 414, 415 with an optical masking element such as a stencil.
- the mirror or stencil may be on an image plane to create a sharp cut.
- Steering element 402, 412 may be, but is not limited to, a mirror, mirrors, beam splitter and optical or mechanical shutter or shutters (e.g., a liquid crystal switchable mirror) combined with one of the above.
- the steering element 402, 412 may be configured to direct a first image component to a small image optical element and to direct a second image component to a large image optical element.
- the large image optical element and the small image optical element are completely separate.
- the small image optical element and large image optical element may share one or more of their constituents.
- the small image optical element and large image optical element may share most of their lenses, and the large image optical element may have extra lenses for making the beam wider which are unreachable to the narrow beam thanks to a reflective polarizer beam splitter.
- a single optical element functions as the large image optical element (or a component of the large image optical element) and the small image optical element (or a component of the small image optical element).
- the single optical element may include one or more electrically tunable lens (e.g., a liquid lens and/or a liquid crystal lens).
- An electrically tunable lens can change their focal length electrically, which means if properly integrated with other lenses, for time-sequential embodiments a single optical element can function as a large image optical element one frame, then as a small image optical element in the next frame.
- the single optical element can become at least a portion of the large image optical element at a first time and can become at least a portion of the small image optical element at a second time.
- the steering element 402, 412 may function as an image separation element, and may separate the first image component from the second image component.
- the optical element 403, 404, 414, 415 may be, but is not limited to, one of the following, or a combination of: lenses, mirrors, prisms, free-form mirrors.
- One of the optical elements 404, 415 may create a small image 417 and the other optical element 403, 414 a comparably large image 416.
- the microdisplay or display 401 creates the image and optically sends it to the image or beam steering element 402.
- the image steering element 402 splits the image into two (or more) images, sending the images to optics creating the low resolution, large image 403 and a high resolution, small image 404.
- the optical output of the optics 403, 404 are sent to a screen 418 or onto the viewer’s retina where the final image is created 405.
- the microdisplay or display 411 creates an image that is split with a beam splitter (such as half silvered mirror or polarizer beam splitter) 412 into two identical images going in different directions.
- a beam splitter such as half silvered mirror or polarizer beam splitter
- One is directed to optics which create a large image 414, while the other goes through a mirror 413 to another optics which creates a small image 415.
- the large image optics 414 create the lower resolution image 416.
- the small image optics 415 creates the higher resolution image 417. Both the lower 416 and higher 417 resolution images are projected on the screen 418 or on the viewer’s retina as seen in Figure 5B.
- Masking of the area of the large image 416 where the small image 417 is can be achieved, again, digitally, by having black pixels displayed there, or optically, for example by having a stencil on an image plane somewhere inside, before or after the optics to physically (optically) mask off that part of the image.
- the positioning of the small image can be achieved with, but not limited to one or more of the following: actuators with mirrors, galvanometer scanners, actuators with wedge (Risley) prisms, actuators with tilting or shifting lenses, as seen in Figure 5A.
- Figure 5 A shows a microdisplay or display 501 creating an image that is sent to an image or beam steering element 502 (could be a beam splitter).
- an image or beam steering element 502 could be a beam splitter.
- One of the two identical images is sent to the large image optical element 503 and the other image is sent to the small image optical element 504.
- the large image optical element 503 and the small image optical element 504 are completely separate.
- the small image optical element 504 and large image optical element 503 may share one or more of their constituents.
- the small image optical element 504 and large image optical element 503 may share most of their lenses, and the large image optical element 503 may have extra lenses for making the beam wider which are unreachable to the narrow beam thanks to a reflective polarizer beam splitter.
- the small image optical element 504 sends the image to an image or beam steering element 506 (could be a mirror).
- the images are then combined into a final image 505 (e.g., into a
- a single optical element functions as the large image optical element 503 (or as a component of the large image optical element 503) and the small image optical element 504 (or as a component of the small image optical element 504).
- the single optical element may include one or more electrically tunable lens (e.g., a liquid lens and/or a liquid crystal lens).
- An electrically tunable lens can change its focal length electrically, which means if properly integrated with other lenses, for time-sequential embodiments a single optical element can function as large image optical element 503 one frame, then as small image optical element 504 in the next frame.
- the two images are optically combined, such as with a beam splitter and viewed directly, or through, but not limited to, an eyepiece or waveguide.
- the optically combined images may be a superimposition of the two images.
- the microdisplay or display 511 sends the image to a beam splitter or a rotating mirror 512 that sends images to the large image optics 514 and to a mirror 513 that redirects the image to the small image optics 515.
- the image is sent to a mirror 519 and then to a beam combiner 518 (e.g., beam splitter) to combine with the output of the large image optics 514.
- the beam combiner 518 From the beam combiner 518, the large image 516 and the small image 517, are sent as a combined image to the viewer’s retina 510 (e.g., a superimposition of the two images).
- each image each frame may be blocked or let to pass accordingly before, inside or after the optical element 514, 515 with an optical or mechanical shutter such as an LCD shutter in order to prevent 514 and 515 from receiving the same image of every frame instead of the different images of different consecutive frames.
- an optical or mechanical shutter such as an LCD shutter
- Figure 5B and 5C One difference between Figure 5B and 5C is that images are illustrated as two lines rather than one before reaching the optical masking elements. This is done to illustrate how the image is masked/cropped by the optical masking elements 530, 531.
- the microdisplay or display 521 sends the images to a beam splitter 522, that sends two identical images, one to a mirror 523 first, to optical masking elements (stencils, physical barriers to hide part of the image) 530, 531.
- the stencil may be on an image plane to create a sharp cut, so can also be inside the optics (524 and 525), or after the optics.
- the images leave from the stencils 530, 531 to the large image optics 524 and to the small image optics 525. From the small image optics 525, the image is sent to a mirror 529 and then to a beam combiner 528 (e.g., beam splitter) to combine with the output of the large image optics 524. From the beam combiner 528, the large image 526 and the small image 527, are sent as a combined image to the viewer’s retina 520.
- a beam combiner 528 e.g., beam splitter
- FIG. 5D a head-mounted display embodiment which uses a single microdisplay or display 551 for both eyes.
- each frame may be used for one projection (large or small image). For example with a 240Hz DLP microdisplay this provides 120Hz refresh rate per image per eye.
- the microdisplay or display 551 sends the image to a beam splitter 560 that sends two identical images, one to a mirror 580 first, to the stencils 561, 571 that mask off the portion of the image not destined for the specific eye.
- the stencils 561, 571 could be shutters such as an LCD shutter or LCD pi-cell so each frame may be sent to one optics and blocked for the rest of the optics 554, 555, 574, 575, such as in the instance seen in Figure 2.
- the stencils 561, 571 could be removed so each frame the whole image may be sent to one optics and blocked for the rest of the optics 554, 555, 574, 575, such as in the instance seen in Figure 2. For example with a 240Hz DLP microdisplay this provides 60Hz refresh rate per image per eye.
- the left stencil (top in the diagram) 561 sends the image to a second beam splitter
- the shutters 562, 563 could be replaced with stencils (a physical barrier to hide part of the image) for the Figure 3 embodiment.
- the stencils have to be on an image plane to create a sharp cut, so can also be inside the optics (554 and 555), or after the optics.
- the small image optics 555 From the small image optics 555, the image is sent to a mirror 559 and then to a beam combiner 558 (e.g., beam splitter) to combine with the output of the large image optics 554. From the beam combiner 558, the large image 556 and the small image 557, are sent as a combined image to the viewer’s retina 550.
- a beam combiner 558 e.g., beam splitter
- the right stencil (bottom in the diagram) 571 sends the image to a second beam splitter 572 which sends two identical images, one to a mirror 573 first, to the two LCD shutters 580, 581 for the Figure 2 embodiment.
- the shutters 580, 581 could be replaced with stencils for the Figure 3 embodiment.
- the stencils may be on an image plane to create a sharp cut, so can also be inside the optics (574 and 575), or after the optics.
- the image is sent to a mirror 579 and then to a beam combiner 578 (e.g., beam splitter) to combine with the output of the large image optics 574.
- a beam combiner 578 e.g., beam splitter
- the large image 576 and the small image 577 are sent as a combined image to the viewer’s retina 570.
- Figure 6B shows an illustration with individual pixels displaying an actual image 604.
- variable-resolution screen method and apparatus described here allows to achieve more resolution visible in one or more parts of the image than is possible with the display technology when used without the methods described here.
- the small high resolution part 603, 606 can be positioned on the final image 601, 604 on the large low resolution part 602, 605 where the viewer’s foveal view is at any given point in time. This allows to always have more pixels or scanlines concentrated in the foveal and optionally also in the near peripheral view of the viewer at any given point in time.
- the positioning of the large low resolution part 602, 605 can be achieved the same way the positioning of the small high resolution part 603, 606, for example to have pixels only in the field of view of the viewer’s eye and not the total field of view of the viewer which takes into account eye rotations.
- variable-resolution screen is achieved by positioning a high resolution narrow video projection over a low resolution wide video projection with mirrors or wedge (Risley) prisms.
- a single video projector such as a single illuminated microdisplay, display, LBS (Laser beam steering) projector or other type of video projector (from now on referred to as“projector”) 401, 411, 501, 511, 521, 551, 5111, 5121, 5151 is operated at fast refresh rates.
- Each consecutive frame (frame n+1) the projector is used to either display a small high resolution part 204 or parts of the final image 205 or a large low resolution part 203 or parts of the final image 205 by sharing the refresh rate of the frames 201, 202 and final image 205 between the latter’s two or more parts 203, 204.
- Persistence of vision blends the two parts 203, 204 into one final projected image 205.
- a single video projector such as a single illuminated microdisplay, display, LBS (laser beam steering) projector or other type of video projector (from now on referred to as“projector”) is optically split into two or more parts 301, 302.
- LBS laser beam steering
- projector other type of video projector
- the two methods can also be combined to allow to create more parts on the final projected image or to allow to create two or more final projected images by sharing both the resolution and refresh rate of the projector between the parts, such as for using a single projector to create final projected images for both eyes in a head-mounted display.
- Second, using video projections has the advantage of allowing to have all of the optical elements including steering elements be much smaller as they can be positioned in the optical design before, or somewhere in between the projection optics which create the large final image on a projection screen.
- the beam angle for each pixel can be narrower than with emissive microdisplays such as OLED or microLED which can allow to provide an optical system with less stray light and be more efficient while providing the same or higher brightness to the viewer.
- a single 16:9 aspect ratio microdisplay or display is split into two parts, for example 1920x1080 pixel microdisplay or display split into a small 1080x1080 pixel high resolution part 301 and a large 840x1080 pixel low resolution part 302 (the latter may then be optically flipped 90 degrees for a better aspect ratio).
- the parts 301 and 302 can be resized and superimposed on each other 305 and the large low resolution part 303 can be masked where the small high resolution part 304 is and where they overlap.
- the masking can further be made more seamless by blending the edges optically or digitally by making the transition less abrupt with a digital resolution falloff in the high resolution small image or dimming the pixels with a falloff on both images.
- the brightness levels between the two parts may be balanced optically such as with neutral density filters or digitally.
- the beam of the projector is steered with a steering element optomechanically or optically, such as, but not limited to, a rotating mirror or beam splitter 402, 412 and an optional mirror 413, to one of two optical elements 403, 404, 414, 415 for each frame.
- a steering element optomechanically or optically such as, but not limited to, a rotating mirror or beam splitter 402, 412 and an optional mirror 413, to one of two optical elements 403, 404, 414, 415 for each frame.
- each beam each frame may be blocked or let to pass accordingly before, inside or after the optical element 403, 404, 414, 415 with an optical or mechanical shutter such as an LCD shutter in order to prevent 403, 414 and 404, 415 from receiving the same beam of every frame instead of the different beams of different consecutive frames.
- an optical or mechanical shutter such as an LCD shutter
- the beam of the projector 401, 411 is steered with a steering element such as, but not limited to, a beam splitter or a mirror on an image plane 402, 412 and an optional mirror 413, to two optical elements 403, 404, 414, 415.
- a steering element such as, but not limited to, a beam splitter or a mirror on an image plane 402, 412 and an optional mirror 413, to two optical elements 403, 404, 414, 415.
- each beam is then masked accordingly before, inside or after the optical element 403, 404, 414, 415 with an optical masking element such as a stencil.
- the mirror or stencil may be on an image plane to create a sharp cut.
- Steering element 402, 412 may be, but is not limited to, a mirror, mirrors, beam splitter and optical or mechanical shutter or shutters combined with one of the above.
- the optical element 403, 404, 414, 415 may be, but is not limited to, one of the following, or a combination of: lenses, mirrors, prisms, free-form mirrors.
- One of the optical elements 404, 415 may create a narrow beam 417 and the other optical element 403, 414 a comparably wide beam 416.
- the projector 411 creates a projection beam that is split with a beam splitter (such as half silvered mirror or polarizer beam splitter) 412 into two identical projection beams going in different directions.
- a beam splitter such as half silvered mirror or polarizer beam splitter
- One is directed to optics 414 which create a wide beam, while the other goes through a mirror 413 to another optics 415 which creates a narrow beam.
- the wide beam optics 414 create the lower resolution image beam 416.
- the narrow beam optics 415 creates the higher resolution image beam 417. Both the lower 416 and higher 417 resolution beams are projected onto the viewer’s retina or screen 418.
- Masking of the area of the wide beam 416 where the narrow beam 417 is can be achieved, again, digitally by having black pixels displayed there, or optically, for example by having a stencil on an image plane somewhere inside, before or after the optics to physically (optically) mask off that part of the projection beam.
- the positioning of the small image of the narrow beam can be achieved with, but not limited to one or more of the following: actuators with mirrors, galvanometer scanners, actuators with wedge (Risley) prisms, actuators with tilting or shifting lenses, as seen in Figure 5A.
- the two beams are projected onto the same screen as seen in Figure 4B or first optically combined, such as with a beam splitter, projected onto a screen and viewed directly, or through, but not limited to, an eyepiece or waveguide. This is seen in the beam steering elements 519 and 518 of Figure 5B.
- the projector 5111 sends the projection beam to a beam splitter or a rotating mirror 5112 that sends projection beams to the wide beam optics 5114 and to a mirror 5113 that redirects the projection beam to the narrow beam optics 5115.
- the beam is sent to a mirror 5119 and then to a beam combiner 5118 (e.g., beam splitter) to combine with the output of the wide beam optics 5114.
- the beam combiner 5118 From the beam combiner 5118, the wide beam 5116 and the narrow beam 5117, are sent as a combined projection beam to the viewer’s retina or the screen 5110.
- each beam each frame may be blocked or let to pass accordingly before, inside or after the optical element 5114, 5115 with an optical or mechanical shutter such as an LCD shutter in order to prevent 5114 and 5115 from receiving the same beam of every frame instead of the different beams of different consecutive frames.
- an optical or mechanical shutter such as an LCD shutter
- FIG. 5G One difference between Figure 5F and 5G is that projection beams are illustrated as two lines rather than one before reaching the optical masking elements. This is done to illustrate how the projection beam is masked/cropped by the optical masking elements 5130, 5131.
- the projector 5121 sends the projection beam to a beam splitter 5122 that sends two identical projection beams, one to a mirror 5123 first, to a stencil (a physical barrier to hide part of the image) 5130, 5131.
- the stencils may be on an image plane to create a sharp cut, so can also be inside the optics (5124 and 5125), or after the optics.
- the beams leave from the stencils 5130, 5131 to the wide beam optics 5124 and to the narrow beam optics 5125. From the narrow beam optics 5125, the beam is sent to a mirror 5129 and then to a beam combiner 5128 (e.g., beam splitter) to combine with the output of the wide beam optics 5124. From the beam combiner 5128, the wide beam 5126 and the narrow beam 5127, are sent as a combined projection beam to the viewer’s retina or screen 5120.
- a beam combiner 5128 e.g., beam splitter
- FIG. 5H a head-mounted display embodiment which uses a single projector 5151 for both screens (for both eyes). First the resolution of the microdisplay or display is split between eyes, then each frame is used for one projection (large or small image). For example with a 240Hz DLP projector this provides 120Hz refresh rate per image per screen.
- the projector 5151 sends the beam to a beam splitter 5160 that sends two identical beams, one reflected from a mirror 5182 first, to the stencils 5161, 5171 that mask off the portion of the image not destined for the specific eye.
- the stencils 5161, 5171 could be shutters such as an LCD shutter or LCD pi-cell, so each frame will be sent to one optics and blocked for the rest of the optics 5154, 5155, 5174, 5175, such as in the instance seen in Figure 2.
- the stencils 5161, 5171 could be removed so each frame the whole image will be sent to one optics and blocked for the rest of the optics 5154, 5155, 5174, 5175, such as in the instance seen in Figure 2. For example with a 240Hz DLP projector this provides 60Hz refresh rate per image per eye.
- the left stencil (top in the diagram) 5161 sends the beam to a second beam splitter 5152 which send two identical beams, one to a mirror 5153 first, to the two LCD shutters 5162, 5163 for the Figure 2 embodiment.
- the LCD shutters 5162, 5163 could be replaced with stencils (a physical barrier to hide part of the projection beam) for the Figure 3 embodiment.
- the stencils may be on an image plane to create a sharp cut, so can also be inside the optics (5154 and 5155), or after the optics.
- the beams leave from the shutters (or stencils) 5162, 5163 to the wide beam optics 5154 and narrow beam optics 5155. From the narrow beam optics 5155, the beam is sent to a mirror 5159 and then to a beam combiner 5158 (e.g., beam splitter) to combine with the output of the wide beam optics 5154. From the beam combiner 5158, the wide beam 5156 and the narrow beam 5157, are sent as a combined beam to the screen 5150 or viewer’s retina.
- the right stencil (bottom in the diagram) 5171 sends the beam to a second beam splitter 5172 which sends two identical beams, one to a mirror 5173 first, to the two LCD shutters 5180, 5181 for the Figure 2 embodiment.
- the LCD shutters 5180, 5181 could be replaced with stencils (a physical barrier to hide part of the projection beam) for the Figure 3 embodiment. This has to be in an image plane to create a sharp cut, so can also be inside the optics (5174 and 5175), or after the optics.
- the beams leave from the LCD shutters (or stencils) 5180, 5181 to the wide beam optics 5174 and narrow beam optics 5175. From the narrow beam optics 5175, the beam is sent to a mirror 5179 and then to a beam combiner 5178 (e.g., beam splitter) to combine with the output of the wide beam optics 5174. From the beam combiner 5178, the wide beam 5176 and the narrow beam 5177, are sent as a combined beam to the screen 5170 or viewer’s retina.
- a beam combiner 5178 e.g., beam splitter
- Figure 6B shows an illustration with individual pixels displaying an actual image 604.
- variable-resolution screen method and apparatus described here allows to achieve more resolution visible in one or more parts of the projected image than is possible with the projector when used without the methods described here.
- variable-resolution screen such as a head-mounted display screen which uses one projector or one per eye with a high pixel or scanline density in the center of the field of view of the viewer and less in the periphery.
- the small high resolution part 603, 606 can be positioned on the final projected image 601, 604 on the large low resolution part 602, 605 where the viewer’s foveal view is at any given point in time. This allows to always have more pixels or scanlines concentrated in the foveal and optionally also in the near peripheral view of the viewer at any given point in time.
- the positioning of the large low resolution part 602, 605 can be achieved the same way the positioning of the small high resolution part 603, 606, for example to have pixels only in the field of view of the viewer’s eye and not the total field of view of the viewer which takes into account eye rotations.
- variable-resolution screen is achieved by shifting/offsetting a small and high resolution image or projection beam over a large and low resolution image or projection beam with optical slabs or mirrors.
- a single display technology such as a microdisplay or display or a single video projector such as a single illuminated microdisplay, display, LBS (laser beam steering) projector or other type of video projector (from now on referred to as“projector”) 401, 411, 501, 511, 521, 551, 2301, 5111, 5121, 5151 is operated at fast refresh rates.
- LBS laser beam steering
- each consecutive frame (frame n+1) the microdisplay, display or projector is used to either display or project a small high resolution part 204 or parts of the final image 205 or a large low resolution part 203 or parts of the final image 205 by sharing the refresh rate of the frames 201, 202 and final image 205 between the latter’s two or more parts 203, 204.
- Persistence of vision blends the two parts 203, 204 into one final image 205.
- Figure 3 shows an alternative embodiment, to achieve a variable-resolution screen a single display technology such as a microdisplay, display or a single video projector such as a single illuminated microdisplay, display, LBS (Laser beam steering) projector or other type of video projector (from now on referred to as“projector”) is optically split into two or more parts 301, 302.
- This method allows a small high resolution part or parts 304 to use more pixels on the final image 305 by sacrificing the resolution of a large low resolution part 303 or parts.
- the two methods can also be combined to allow to create more parts on the final image or to allow to create two or more final images by sharing both the resolution and refresh rate of the microdisplay, display or projector between the parts, such as for using a single microdisplay, display or projector to create final images for both eyes in a head-mounted display.
- a single 16:9 aspect ratio microdisplay or display is split into two parts, for example 1920x1080 pixel microdisplay or display split into a small 1080x1080 pixel high resolution part 301 and a large 840x1080 pixel low resolution part 302 (the latter may then be optically flipped 90 degrees for a better aspect ratio).
- the parts 301 and 302 can be resized and superimposed on each other and the large low resolution part 303 can be masked where the small high resolution part 304 is and where they overlap.
- the masking can further be made more seamless by blending the edges optically or digitally by making the transition less abrupt with a digital resolution falloff in the high resolution small image 304 or narrow beam or dimming the pixels with a falloff on both images or beams.
- the brightness levels between the two parts may be balanced optically such as with neutral density filters or digitally.
- each image or beam each frame may be blocked or let to pass accordingly before, inside or after the optical element 403, 404, 414, 415 with an optical or mechanical shutter such as an LCD shutter in order to prevent 403, 414 and 404, 415 from receiving the same image or beam of every frame instead of the different images or beams of different consecutive frames.
- an optical or mechanical shutter such as an LCD shutter
- the image of the microdisplay or display or the beam of the projector 401, 411 is steered with a steering element such as, but not limited to, a beam splitter or a mirror on an image plane 402, 412 and an optional mirror 413, to two optical elements 403, 404, 414, 415.
- a steering element such as, but not limited to, a beam splitter or a mirror on an image plane 402, 412 and an optional mirror 413, to two optical elements 403, 404, 414, 415.
- each image or beam is then masked accordingly before, inside or after the optical element 403, 404, 414, 415 with an optical masking element such as a stencil.
- the mirror or stencil may be on an image plane to create a sharp cut.
- Steering element 402, 412 may be, but is not limited to, a mirror, mirrors, beam splitter and optical or mechanical shutter or shutters combined with one of the above.
- the optical element 403, 404, 414, 415 may be, but is not limited to, one of the following, or a combination of: lenses, mirrors, prisms, free-form mirrors.
- One of the optical elements 404, 415 may create a small image or narrow beam
- the positioning of the small image or narrow beam can be achieved with, but not limited to one or more of the following: optical slabs or mirrors 506, 519, 529, 559, 579, 2310, 2311, 5119, 5129, 5159, 5179.
- the two images or beams are optically combined, such as with a beam splitter and viewed directly, or through, but not limited to, an eyepiece or waveguide.
- FIG. 5E we see a variant of Figure 5B or 5F with two tilting optical slabs 2310 and 2311.
- the microdisplay, display or projector 2301 creates the image or beam and sends the image or beam through a beam splitter or a rotating mirror 2302. Two identical images or beams are sent from the beam splitter 2302. One image or beam is sent through the low resolution, large image or wide beam optics 2304, where the high resolution portion is masked off in case of using the method in Figure 3, and then to the beam splitter 2308, used here as a beam combiner.
- the other image or beam is sent from the beam splitter 2302 to a mirror 2303 to the high resolution, small image or narrow beam optics 2305, where the low resolution image is masked off in case of using the method in Figure 3.
- the image or beam is reflected off a mirror 2309 to two beam steering elements 2310, 2311, to offset the small image or narrow beam in the axis (after it will be combined with the beam combiner 2308) of the large image or wide beam.
- the beam steering elements are two thick optical slabs 2310, 2311 that rotate in X and Y axis respectively to offset the image or beam in these two respective axis.
- the optical slabs 2310, 2311 may each be substituted with a single mirror that rotates in both axis or two rotating/tilting mirrors, to name a few possible alternative embodiments.
- the shifted image or beam travels to the beam splitter 2308, used here as a beam combiner.
- the beam splitter 2308 From the beam splitter 2308, the low resolution, large image or wide beam 2306 and the high resolution, small image or narrow beam 2307 travel to the screen 2300 or viewer’s retina.
- each image each frame may be blocked or let to pass accordingly before, inside or after the optical element 2304, 2305 with an optical or mechanical shutter such as an LCD shutter in order to prevent 2304 and 2305 from receiving the same image of every frame instead of the different images of different consecutive frames.
- an optical or mechanical shutter such as an LCD shutter
- Figure 6B shows an illustration with individual pixels displaying an actual image 604.
- the projection beam or image is steered and gets a perspective distortion, as seen in Figure 7B, and some optical aberrations which get progressively worse as the image or beam is steered farther away from the center.
- the image 702 may be pre-distorted digitally which reduces the possible size of the high resolution small image and the number of utilized pixels significantly.
- Figure 7A is an original image 701
- Figure 7B is a perspective distorted image 702.
- the beam or image can be shifted by, but not limited to, two tilting/rotating optical slabs, one for each axis, two dual axis tilting/rotating mirrors such as OptotuneTM MR-15- 30-PS-25x25D or four tilting/rotating mirrors (two per axis).
- an optical slab 902 is a glass slab or a plastic polymer slab clear in the visible spectrum which allows to shift/offset an image or projection beam 903.
- Both an image as well as a projection beam 903 may be shifted with this method.
- the latter allows to have the slabs 902 relatively small which can direct the projection beam to projection optics which can produce a large projected image not requiring much more magnification by the eyepiece lens, waveguide or similar optics in a head-mounted display device.
- an image may be shifted by this method as well when the magnification can be performed by the eyepiece optics, limited amount of shifting is needed or limited amount of magnification is needed by the eyepiece lens, waveguide or similar optics.
- FIG. 9B we see a 20x20x20mm PMMA (Poly(methyl methacrylate)) polymer optical slab 902 with a collimated 5mm wide 638nm wavelength beam 903 passing through it and being shifted.
- the slab can tilt +34 degrees (the range is ⁇ 34 degrees) and offset the beam by up to 8.04 mm.
- a 16.08mm shift would allow to move the high resolution image which the beam contains by over 64 degrees or more which is more than the average human can comfortably rotate their eyes.
- Slight dispersion of an RGB image or projection beam 903 caused by the optical slab 902, 904 can be compensated for by digitally offsetting each color channel by several pixels accordingly. Since offsetting may only be required to be done only to one or two color channels with higher refractive index, one or two color channels won’t be able to reach the same offset on the edges of the image or projection beam 903 which may be resolved by digitally or optically cropping the image or projection beam 903 slightly on the edges so the pixels in each color channel can be offset as much as is required to undo the separation of the color channels caused by dispersion. This loss of pixels on the edges is still negligible compared to loss of pixels/detail due to correction of a perspective distortion from previous embodiments.
- FIG. 9D there are two views of a single slab 902, 904 superimposed over each other to illustrate how much the beam offsets from one angle to the other.
- the slab view 904 is tilted -34 degrees, causing the beam 903 to be offset 8.04mm downwards while slab view 902 is tilted +34 causing the beam 903 to be offset 8.04mm upwards.
- the beam 903 may be offset up and down, creating images or beams at most 16.08mm apart.
- the slabs 902, 904 can also be swapped with 2d mirrors (dual axis tilting/rotating mirrors such as OptotuneTM MR-15-30-PS-25x25D) or two mirrors 1001, 1002 or 1003, 1004. This is a savings in cost traded off with bigger space requirements. On the other hand, dispersion is not an issue with mirrors.
- Two 2D mirrors rotating in two axis or four mirrors 1101, 1102, 1103, 1104 may be used to shift the beam or image in two axis as seen in Figure 11.
- both mirrors 1101, 1102 have a top-down view purely for illustrative purposes, the second set of mirrors 1103, 1104 are in another axis.
- Figure 12 shows another embodiment. Either the second set of mirrors 1204,
- Dove prism 1203 or an equivalent mirror assembly may be placed between the two 2d mirrors or mirror pairs 1201, 1202 and 1204, 1205 to flip the axis of the offset performed by the previous set and have the mirrors and the components which shift/offset them in the same axis.
- Dove prism proportions and angle are not accurate in this drawing, nor is the path the ray travels inside the Dove prism itself).
- variable-resolution screen method and apparatus described here allows to achieve more resolution visible in one or more parts of the final image than is possible with the display, microdisplay or projector when used without the method described here.
- variable-resolution screen such as a head-mounted display screen which uses as little as one microdisplay, display or projector or one per eye with a high pixel or scanline density in the center of the field of view of the viewer and less in the periphery.
- the smaller high resolution part can be moved on the final image or screen on the bigger low resolution part where the viewer’s foveal view is at any given point in time. This allows to always have more pixels or scanlines concentrated in the foveal and optionally also in the near peripheral view of the viewer at any given point in time.
- the positioning of the bigger low resolution part can be achieved the same way the positioning of the smaller high resolution part, for example to have pixels only in the field of view of the viewer’s eye and not the total field of view of the viewer which takes into account eye rotations.
- variable-resolution screen is achieved by creating and digitally and optically positioning a small and high resolution image or projection over a large low resolution image or projection with no mechanically moving parts.
- the image source for the at least one large low resolution part 201 and at least one small high resolution part 202 can be the same microdisplay, display or projector with consecutive frames (frame n and frame n+1) distributed between the two or more parts 203, 204 of the final image or beam (see Figure 2).
- the parts of the images of the microdisplay, display or projector could be optically split into two 301, 302 or more and allocated between the at least one large low resolution part 303 and at least one small high resolution part 304, as in Figure 3.
- the at least one large low resolution part and at least one small high resolution part can have a different microdisplay, display or projector as image source each as in Figure 13.
- Second, repositioning of the small high resolution part can take as low as a few microseconds to a few milliseconds, based on the speed of the optical masking element used as described below.
- actuators it is difficult to get actuators to rotate a mirror, prism or slab as fast as the saccadic movement of the human eye while keeping such a motor as small as possible for a wearable device.
- an image or projection beam is optically duplicated across the whole or most of the screen or the viewer’s retina or part of the screen the human eye can rotate and focus at.
- lens arrays For illustrative and purposes of showing an example a single or double sided lens array is used, however a multi element lens and/or lens array setup may be used to reduce optical aberrations in the duplicated images or video projections.
- Figure 13 shows a two microdisplays, displays or projectors 1301, 1302 embodiment using a lens array.
- the large image or wide beam is created by the first microdisplay, display or projector 1301 and sent directly (or through a large image or wide beam optics) to the final image 1305.
- the second microdisplay, display or projector 1302 creates the small image or narrow beam, sending it to the lens array (or other duplication element) 1303 and then to an optical masking element 1304 to mask off (hide) the duplicates in the area outside of the one duplicate image to be shown.
- the image or beam then proceeds to the final image 1305 where it is combined with the large image or wide beam from the first microdisplay, display or projector 1301.
- Figure 14 shows a similar embodiment, using a single microdisplay, display or projector 1401.
- the image or beam proceeds from the microdisplay, display or projector 1401 to an image or beam steering element 1402.
- the steering element 1402 splits the image or beam, with the large image portion of the final image or beam sent directly (or through a large image or wide beam optics) to the final image 1405 (in some embodiments, such as in Figure 3, the image is masked to extract small and large image portions accordingly first).
- the small image portion of the final image or beam is sent to the lens array (or other duplication element) 1403, and then to the optical masking element 1404 to mask off (hide) the duplicates in the area outside of the one duplicate image to be shown.
- This small image or narrow beam is then combined with the large image or wide beam from the steering element 1402 to form the final image 1405.
- Figure 15 shows the simplest setup of how display, microdisplay or projection beam can be duplicated this way and Figures 16A and 16B show the simulated result.
- the image source (display, microdisplay or projector) 1501 sends the image to a lens 1502 which sends it to the aperture stop 1504. The image or beam then proceeds to the lens array 1503 and then to the screen 1505 or viewer’s retina.
- Figures 16A and 16B show the simulated result.
- Figure 16A is the original image from the display, microdisplay or projector 1601 and
- Figure 16B is the resulting image on the screen or viewer’s retina 1602.
- Figure 17A shows a simple setup with one possible position of the optical masking element.
- 1701 is a microdisplay, display or projector
- 1702 is the light cone (beam) of a single pixel from 1701.
- 1703 is a simplified illustration of a multi-element lens.
- 1704 is the first lens array which focuses the pixel light cones (beams) to pixels on a LCD microdisplay optical masking element 1705 on an intermediate image plane
- 1706 is the second lens array which again focuses the pixel light cones on the final image plane on a projection screen 1707 or the viewer’s retina.
- the second lens array 1706 can also be replaced with other optics such as an ordinary projection lens or eyepiece lens.
- Figure 17B shows a reflective microdisplay such as LCoS or DLP used for the optical masking element.
- 1711 is a microdisplay, display or projector generating the image or beam
- 1712 is a light cone (beam) of a single pixel from 1711
- 1713 is a simplified illustration of a multi-element lens
- 1714 is the first lens array which focuses the pixel light cones (beams) to pixels on a LCoS microdisplay optical masking element 1715 on an intermediate image plane
- 1717 is the second lens array which again focuses the pixel light cones (beams) on the final image plane on a projection screen 1718 or the viewer’s retina.
- a polarizer beam splitter or a PBS (polarizer beam splitter) cube 1716 is used to redirect the image or beam reflected off the LCoS microdisplay optical masking element 1715 90 degrees to the side rather than back to the first lens array.
- the second lens array 1717 can also be replaced with other optics such as an ordinary projection lens or eyepiece lens.
- a TIR or RTIR (total internal reflection) prism can be used in place of the polarizer beam splitter or PBS (polarizer beam splitter) cube 1716.
- Figure 17C shows that it is also possible to use a display, not microdisplay, such as an LCD display with its reflective and backlight layers removed as the optical masking element.
- 1721 is a microdisplay, display or projector generating the image or beam
- 1722 is a light cone (beam) of a single pixel from 1721
- 1723 is a simplified illustration of a multi-element lens
- 1724 is the lens array which focuses the pixel light cones (beams) to pixels on a screen 1727 on an image plane behind a LCD display optical masking element 1726 by reflecting the beam with a beam splitter 1725.
- the image from second display 1728 also reflects from the beam splitter thus both the second display and the screen are seen by the eye 1720 directly or through an eyepiece or waveguide 1729.
- the screen 1727 is used to display the small high resolution image and the display 1728 is used to display the large low resolution image of the final combined image combined by the beam splitter 1725.
- a LCD display with its reflective and backlight layers removed as an optical masking element with a single microdisplay, display or projector (or two, as seen in Figure 13) generating the image or beam without a second display 1728, as illustrated in Figure 17D.
- a beam splitter 1725 is also not necessary as illustrated in Figure 20 and Figure 21.
- the beam splitter 1725 is a reflective polarizer beam splitter.
- a first quarter wave plate (not shown) may be positioned between beam splitter 1725 and screen 1728 and/or a second quarter wave plate (not shown) may be positioned between beam splitter 1725 and screen 1727.
- the quarter wave plates may rotate the polarization of light reflecting off of the screen 1728 and screen 1727, respectively.
- FIG. 17D the elements for generating a duplicated image or beam are not illustrated and are in 1731 which represents a microdisplay, display or projector or two microdisplays, displays or projectors with the wide beam and duplicated beam already optically combined as described in Figure 13 and Figure 14.
- Light cone (beam) of a single pixel of the wide beam 1732 and light cone (beam) of single pixel of a duplicate beam 1733 both focus to pixels on a screen 1736 on an image plane behind a LCD display optical masking element 1735 by being reflected from a beam splitter 1734.
- the screen 1736 is seen by the eye 1738 directly or through an eyepiece or waveguide 1737.
- the beam splitter 1734 is a reflective polarizer beam splitter.
- a first quarter wave plate (not shown) may be positioned between beam splitter 1734 and screen 1736.
- the quarter wave plate may rotate the polarization of light reflecting off of the screen 1736.
- a beam splitter may be used and also a second screen may be used as illustrated in Figure 17E.
- optical system 1741 which represents one or more of a microdisplay, display or projector or two microdisplays, displays or projectors, an image steering element, small and/or large image optical elements, an image separation element, and/or a beam combiner.
- the optical system 1741 includes one or more image source, an image steering element, a small image optical element, a large image optical element, and a beam combiner.
- the image steering element may be configured to separate an image into a first image component and a second image component as well as to direct the first image component to a first destination and to direct the second image component to a second destination.
- the wide beam (e.g., representing a low resolution, large image) and duplicated beam (e.g., representing a plurality of duplicates of a high resolution, small image) may already be optically combined as described in Figure 13 and Figure 14 at the output of the optical system 1741.
- the wide beam may be or represent a low resolution, large image
- the duplicated beam may be or represent a plurality of duplicates of a high resolution, small image.
- the low resolution, large image and the plurality of duplicates of the high resolution, small image may have been optically combined into a combined image as described in Figure 13 and Figure 14.
- Light cone (beam) of a single pixel of the wide beam 1742 and light cone (beam) of a single pixel of a duplicate beam 1743 may focus to pixels on a second screen 1747 and screen 1746 respectively, the latter on an image plane behind an optical masking element 1745 (e.g., which may be an LCD display optical masking element or another type of optical masking element) by being reflected from a beam splitter 1744.
- the wide beam 1742 passes through the beam splitter 1744 and the duplicate beam gets reflected from the beam splitter 1744 instead due to these beams having different polarization (or in the case the beam splitter is a band pass filter or dichroic filter, having different light wavelengths).
- the low resolution, large image may pass through the beam splitter 1744 onto screen 1747, and the plurality of duplicates of the high resolution, small image may be reflected off of the beam splitter 1744 and onto screen 1746.
- the optical masking element 1745 may be positioned between the screen 1746 and the beam splitter 1744, and may mask off one or more of the plurality of duplicates of the high resolution, small image such that a single duplicate of the high resolution, small image remains, as described above.
- the screens 1746 and 1747 are optically combined by the beam splitter 1744 and seen by the eye 1749 directly or through the eyepiece or waveguide 1748. Accordingly, beam splitter 1744 may recombine the single duplicate of the high resolution, small image with the low resolution, large image to produce a variable resolution image that may be directed to the eyepiece or waveguide 1748 or focused directly onto the eye 1749 of a viewer.
- the beam splitter 1744 is a reflective polarizer beam splitter.
- a first quarter wave plate (not shown) may be positioned between beam splitter 1744 and screen 1747 and/or a second quarter wave plate (not shown) may be positioned between beam splitter 1744 and screen 1746.
- the quarter wave plates may rotate the polarization of light reflecting off of the screen 1747 and screen 1746, respectively, to permit the reflected light from the screen 1747 to reflect off of the beam splitter 1744 (reflective polarizer beam splitter) and to permit the reflected light from the screen 1746 to pass through the beam splitter 1744 (reflective polarizer beam splitter) and arrive at eye 1749 and/or eyepiece or waveguide 1748.
- FIG 17F the elements for generating a duplicated image or beam are not illustrated and are in 1751 which represents a microdisplay, display or projector or two microdisplays, displays or projectors with the wide beam and duplicated beam already optically combined as described in Figure 13 and Figure 14.
- Light cone (beam) of a single pixel of the wide beam 1752 and light cone (beam) of single pixel of a duplicate beam 1753 both focus to pixels on a screen 1756 on an image plane behind a LCD display optical masking element 1755 by being reflected from a beam splitter 1754.
- the screen 1756 is seen by the eye 1759 directly or through the eyepiece or waveguide 1757.
- a switchable liquid crystal polarization rotator display is used which is an LCD display optical masking element without polarizers.
- a single polarizer 1758 not two as on LCD display optical masking elements and displays, is placed before the viewer’s eye 1759 and in front of the eyepiece or waveguide 1757 or somewhere before it or left on the LCD display optical masking element 1755.
- the wide beam in this instance is not polarized or in the polarization state the polarizer 1758 is not going to filter out after the wide beam passes through the switchable liquid crystal polarization rotator/LCD display optical masking element 1755.
- the duplicated beam gets masked as expected by the LCD display optical masking element 1755 and the polarizer 1758 while the wide beam does not or gets masked where the duplicated beam is not masked.
- the beam splitter 1754 is a reflective polarizer beam splitter.
- a first quarter wave plate (not shown) may be positioned between beam splitter 1754 and screen 1756.
- the quarter wave plate may rotate the polarization of light reflecting off of the screen 1756.
- Figure 17G illustrates the same system as Figure 17F sans the beam splitter 1754.
- the elements for generating a duplicated image or beam are not illustrated and are in 1761 which represents a microdisplay, display or projector or two microdisplays, displays or projectors with the wide beam and duplicated beam already optically combined as described in Figure 13 and Figure 14.
- Light cone (beam) of a single pixel of the wide beam 1762 and light cone (beam) of single pixel of a duplicate beam 1763 both focus to pixels on a screen 1765 on an image plane behind a LCD display optical masking element 1764.
- the screen 1765 is seen by the eye 1768 directly or through the eyepiece or waveguide 1766.
- a switchable liquid crystal polarization rotator display is used which is an LCD display optical masking element without polarizers.
- a single polarizer 1767, not two as on LCD display optical masking element and displays, is placed before the viewer’s eye 1768 and in front of the eyepiece or waveguide 1766 or somewhere before it or left on the LCD display optical masking element 1764.
- the wide beam in this instance is not polarized or in the polarization state the polarizer 1767 is not going to filter out after the wide beam passes through the switchable liquid crystal polarization rotator/LCD display optical masking element without the polarizers 1764.
- the duplicated beam gets masked as expected by the LCD display optical masking element without the polarizers 1764 and the polarizer 1767 while the wide beam does not or gets masked where the duplicated beam is not masked.
- optical masking element With the optical masking element it is possible to show one of the duplicate images at a time, however with digital manipulation of the source frame it is possible to have a digital and optical reconstruction of the original image visible anywhere on the duplicated image array area while hiding everything else with a positional accuracy up to the pixel resolution of the optical masking element and positioning speed equal to the few microsecond to millisecond pixel switching speed of the optical masking element.
- the optical masking elements discussed such as DLP, LCoS or LCD microdisplays or LCD displays are usually not double the resolution of the lens array but much more, the images can be partitioned into 4 rectangles and rearranged digitally not only at the middle of the image but at any desired location on the image as seen in 1901, 1902, 1903, 1904 in Figure 19 with a possible limitation being the resolution of the source image display, microdisplay or projector and the resolution of the optical masking element.
- the visible portion from the optical masking element cannot be larger than the size of a single duplicate image from the array.
- Figure 20 shows a direct embodiment of the mounting of the present inventions in a head-mounted display.
- the variable-resolution optics 2003 as shown in Figures 4A, 4B, 5, 13, 14, 17 produces the high resolution small image 2005 and the low resolution large image 2006 that are sent directly to the screen 2004.
- a human eye 2001 looks through a lens 2002 or other optics that collects the light 2007 from the image on the screen 2004.
- Figure 21 shows an indirect embodiment of the mounting of the present inventions in a head-mounted display.
- the variable-resolution optics 2103 as shown in Figures 4A, 4B, 5, 13, 14, 17 produces an image that is reflected off of a mirror 2108.
- the high resolution small image 2105 and the low resolution large image 2106 from the mirror 2108 are sent to the screen 2104.
- a human eye 2101 looks through a lens 2102 or other optics that collects the light 2107 from the image on the screen 2104.
- Figure 22 shows an indirect embodiment with a beam splitter of the mounting of the present inventions in a head-mounted display.
- the variable-resolution optics 2203 as shown in Figures 4A, 4B, 5, 13, 14, 17 produces an image that is reflected off of a mirror 2208.
- the mirror 2208 reflects the light to a beam splitter 2209 which reflects the high resolution small image 2205 and the low resolution large image 2206 onto the screen 2204.
- a human eye 2201 looks through a lens 2202 or other optics and through the beam splitter 2209 to see the light 2207 from the image on the screen 2204.
- the beam splitter 2209 is a reflective polarizer beam splitter.
- a quarter wave plate (not shown) may be positioned between beam splitter 2209 and screen 2204.
- the quarter wave plate may rotate the polarization of light reflecting off of the screen 2204 to permit the reflected light from the screen 2204 to pass through the beam splitter 2209 (reflective polarizer beam splitter) and arrive at eye 2201 and/or eyepiece or waveguide 2202.
- Figure 23 illustrates an embodiment that uses a combination of a first optical source that outputs an image onto a screen to show a first portion of a variable resolution image and second optical source to show a second portion of the variable resolution image.
- the first optical source is a projector that projects the image onto a projection screen
- the second optical source is a display or microdisplay.
- An optical system 2341 may include the elements for generating a duplicated image or beam, as discussed above.
- the optical system may include, for example, an image source such as a microdisplay, display or projector, and may further include a lens array that produces a duplicated beam (e.g., duplicates of a high resolution, small image).
- a light cone (beam) of a single pixel of a duplicate beam 2343 may focus to pixels on a screen 2346.
- the screen 2346 may be on an image plane behind an optical masking element 2345 (e.g., which may be an LCD display optical masking element or another type of optical masking element) by being reflected from a beam splitter 2344.
- an optical masking element 2345 e.g., which may be an LCD display optical masking element or another type of optical masking element
- the optical masking element 2345 may be positioned between the screen 2346 and the beam splitter 2344, and may mask off one or more of the plurality of duplicates of the high resolution, small image such that a single duplicate of the high resolution, small image remains, as described above.
- a second image source 2347 may be a display or microdisplay, such as an organic light emitting diode (OLED) display, a liquid crystal display (LCD), or other screen display.
- OLED organic light emitting diode
- LCD liquid crystal display
- the second image source 2347 may output a low resolution, large image
- the single remaining duplicate of the high resolution, small image (represented by a single beam 2370) may pass through the beam splitter 2344 toward the 2349, eyepiece and/or waveguide 2348.
- the single remaining duplicate of the high resolution, small image may merge with (e.g., be superimposed onto) the low resolution, large image to form a variable resolution image that may be directed to the eyepiece or waveguide 2348 or focused directly onto the eye 2349 of a viewer.
- Reflective and transmissive microdisplays or displays such as DLP, LCoS and
- LCD have opaque or non-reflective gaps between each individual pixel or subpixel. If such a microdisplay or display is used as an optical masking element and is placed exactly on an intermediate image plane and the pixel size of the image projected onto it is smaller or close to the size of the pixel gap, resolution will be lost due to some pixels being completely or partially projected on these opaque or non-reflective gaps. This can cause a“screen-door effect,” in which a grid of horizontal and vertical black lines may appear between pixels. Furthermore, if resolution is added, any screen-door effect from the optical masking element microdisplay or display will remain.
- One possible solution to this problem is having the optical masking element slightly offset to the intermediate image plane.
- the optical masking element may be offset from the focal plane of the small image optical element, may be offset from a focal plane of a large image optical element, or may be offset from a focal plane of an optical system described herein. This does have the side effect of de-focusing the mask and mask edges. However, as has been mentioned previously, the defocusing of the mask and/or mask edges may actually be a desired effect in some embodiments.
- Figure 24A illustrates a source image, in accordance with an embodiment.
- Figure 24B illustrates the source image of Figure 24A on an optical masking element that is on an intermediate image plane, in accordance with an embodiment. As shown, there are gaps between pixels that show up as a grid of horizontal and vertical black lines.
- Figure 24C illustrates the source image of Figure 24A on an optical masking element that is slightly offset from the intermediate image plane (focal plane), in accordance with an embodiment. As shown, the screen-door effect is minimized.
- the duplicate or duplicates which are to be reflected and transmitted can have their corresponding pixels on the optical masking element also be displaying the same image, albeit at a lower resolution.
- the optical masking element (or a different optical masking element) may not simply fully transmit or reflect the low resolution, large image but may also display the same low resolution, large image. This may serve two purposes:
- the contrast of the final image can be enhanced. If the optical masking element is slightly offset to the intermediate image plane, the low resolution version of the image displayed by the optical masking element will become blurred but also benefit from not having sharp comers on its pixels. The resulting effect is very similar to one achieved by a technology in LCD TVs and monitors called“full-array local dimming”. This may be used both for the high resolution, small image as well as low resolution, large image.
- the optical masking element may be significantly higher than the LED array inside full-array local dimming LCD TVs and monitors, and also since the resolution of the low resolution, large image and the resolution of the optical masking element may be the same, and also since human vision has lower acuity for chroma (color) than for luminance (brightness), the optical masking element may also be used not only for enhancing contrast but also enhancing color depth (bit depth) of the final image. The resulting effect is very similar to one achieved by a video encoding and decoding technique of having lower resolution for chroma (color) than luminance (brightness) called“chroma subsampling.”
- This may be used both for the high resolution small image as well as low resolution large image.
- Figure 25 shows how spatially modulating an image twice or spatially modulating two images which store different bit depth (color depth) information of an original image, from left to right, produces a higher contrast and/or higher bit depth (color depth) image on the right.
- an original image 2505 is passed through an optical mask.
- the optical mask may be a display or microdisplay that displays a copy of the image 2510.
- the original image 2505 and the copy of the image 2510 may be combined to form merged image 2515, which may have an improved contrast and/or an improved color depth (bit depth) as compared to the original image 2505.
- Figure 26 shows, from left to right, how spatially modulating a high resolution, small image again or spatially modulating a different bit depth (color depth) information of the high resolution, small image on the optical masking element, where it is displayed at a lower resolution, produces a higher contrast and/or higher bit depth (color depth) image on the right.
- a single duplicate of a high resolution, small image 2605 may be output by a lens array.
- An optical masking element may mask off other duplicates of the high resolution, small image, and may also display a copy of the high resolution, small image 2610.
- the copy of the high resolution, small image 2610 may have a lower resolution than the duplicate of the high resolution, small image 2605.
- the single duplicate of the high resolution, small image 2605 may be combined with the copy of the high resolution, small image 2610 to form a merged high resolution, small image 2615, which may have an improved contrast and/or an improved color depth (bit depth) as compared to the single duplicate of the high resolution, small image 2605 alone.
- the microdisplay, display or projector may store first set of bit depth (color depth) of the final image and the optical masking element microdisplay or display may display the remainder.
- bit depth color depth
- the optical masking element microdisplay or display may display the remainder.
- an OLED microdisplay may display 8 bit pixels and then the optical masking element LCoS, LCD or DLP microdisplay may be used to modulate the pixels again to reach 10 bit or more bit depth (color depth) on the final image.
- the microdisplay, display or projector may store first set of bit depth (color depth) of the final image and the optical masking element microdisplay or display may again display the remainder.
- bit depth color depth
- an LCoS microdisplay may display 8 bit pixels and then the optical masking element LCoS, LCD or DLP microdisplay may be used to modulate the pixels again to reach 10 bit or more bit depth (color depth) on the final image.
- a single microdisplay, display or projector can also refer to microdisplays, displays or projectors where a separate display or microdisplay panel is used for each color channel and they are optically combined such as with a trichroic prism, X-cube prism or dichroic filters.
- three LCoS microdisplays may display 8 bit pixels each and then an optical masking element LCoS, LCD or DLP microdisplay may be used to modulate the optically combined 24 (8x3) bit pixels again to reach 30 bit or more bit depth (color depth) on the final image.
- variable-resolution screen may serve more purposes in addition to creating a final variable resolution image, as a variable-resolution screen may also be useful for allowing the user to switch between these optical elements for controlling the field of view of the screen.
- the variable-resolution screen apparatus is to be used as a wearable display, the different small or large optics can be switched between to optically adjust the size of the virtual display. Doing so by digital means instead degrades resolution.
- one of the optical elements may include a user-controlled zoom lens to adjust the size of the virtual display to any desired size within a range.
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Priority Applications (4)
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EP20781810.5A EP3949386A4 (en) | 2019-03-29 | 2020-03-19 | Method and apparatus for a variable-resolution screen |
KR1020217034969A KR20210142726A (en) | 2019-03-29 | 2020-03-19 | Method and apparatus for variable resolution screens |
JP2021560376A JP7523466B2 (en) | 2019-03-29 | 2020-03-19 | Method and apparatus for variable resolution screens - Patents.com |
CN202080025649.2A CN113748671B (en) | 2019-03-29 | 2020-03-19 | Method and apparatus for variable resolution screen |
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US16/370,694 US10466489B1 (en) | 2019-03-29 | 2019-03-29 | Methods and apparatus for a variable-resolution screen |
US16/370,694 | 2019-03-29 | ||
US16/565,327 | 2019-09-09 | ||
US16/565,328 | 2019-09-09 | ||
US16/565,327 US10649217B1 (en) | 2019-03-29 | 2019-09-09 | Method and apparatus for a variable-resolution screen |
US16/565,328 US10554940B1 (en) | 2019-03-29 | 2019-09-09 | Method and apparatus for a variable-resolution screen |
US16/719,824 | 2019-12-18 | ||
US16/719,824 US10958884B1 (en) | 2019-03-29 | 2019-12-18 | Method and apparatus for a variable-resolution screen |
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US20100097393A1 (en) * | 2008-10-17 | 2010-04-22 | Seiko Epson Corporation | Display apparatus |
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US20100097393A1 (en) * | 2008-10-17 | 2010-04-22 | Seiko Epson Corporation | Display apparatus |
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