Near-eye display with arrayed optics

Abstract

Transparent organic light-emitting diodes (OLEDs) can be used as luminescent pixels in near-eye displays for augmented reality applications. Light from these pixels can be switched and / or directed using tunable beam-guiding and focusing elements, also known as tunable microlenses. These tunable microlenses are arranged in an array and paired with the pixel array, for example, by being embedded in a spectacle lens. The tunable microlenses use rapidly switching half-wave plates to selectively focus and / or tilt the light from the pixels. By switching the light from the pixels between resolvable positions / angles at a rate faster than the flicker fusion threshold (e.g., 60 Hz), the tunable microlenses can efficiently double the apparent resolution of the near-eye display. And by switching between focused and unfocused states at the same rate, the tunable microlenses can efficiently overlay virtual images from the pixels onto a real-world image visible through the pixels.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Application No. 62 / 950,707, filed December 19, 2019, and U.S. Application No. 62 / 946,498, filed December 11, 2019, pursuant to 35 U.S.C., § 119(e). Each of these applications is incorporated herein by reference in its entirety. Background Technology

[0003] A typical near-eye display includes an image generator for producing an image, an optical combiner for combining the image with ambient light, and imaging optics for focusing the image for a person using the near-eye display. The image generator may have pixels that reflect light (e.g., liquid crystal on a silicon device) or pixels that emit light (e.g., an array of organic light-emitting diodes (OLEDs)). In either case, the image generator is typically not within the person's line of sight. Alternatively, it may be outside the person's field of vision and project a beam of light at an angle to the person's line of sight.

[0004] An optical combiner brings light from an image generator into a person's line of sight. For example, an optical combiner could be a cube beamsplitter, with one face or port perpendicular to the person's line of sight and facing their eyes. Light from the image generator enters one of the other ports of the beamsplitter and is redirected through the port facing the person's eyes. If the near-eye display is an augmented reality display, the optical combiner combines light from the image generator with light from the outside world and projects the combined light into the person's eyes.

[0005] Imaging optics focus the image generated by the image generator. Imaging optics can be pupil-forming or non-pupil-forming. Pupil-forming optics produce an intermediate image at a point between the image generator and the eye. This image should be formed at a position far enough from the eye so that the eye can focus the image about the distance. Non-pupil-forming optics do not produce an intermediate image. Instead, they typically focus the image at infinity so that the image becomes clear when the eye is relaxed (i.e., focused at a distance). The parameters of imaging optics in near-eye displays include: (1) eye clearance, the distance between the edge of the last optic and the exit pupil, typically 20 mm; (2) eye relief, the distance between the apex of the last optic and the exit pupil; (3) eyebox (usually equivalent to the exit pupil), which includes the angular and lateral eye positioning range from which the entire image generated by the display can be seen at the eye relief distance; (4) depth of field; and (5) field of view. Summary of the Invention

[0006] In recent years, perspective image generators have become available in the form of transparent OLED arrays. Near-eye displays or other perspective displays with transparent OLED arrays do not require optical combiners; instead, the perspective display can be placed directly within a person's line of sight and modulated to produce changing virtual images. Optics between the perspective display and the person's eyes help to focus the virtual image.

[0007] The technology of this invention utilizes a perspective display coupled to dynamic, switchable optics to focus a virtual image for the user. This technology can be implemented as a near-eye display, which can be very close to the eye (e.g., similar to eyeglasses) and can be used as an augmented reality device. This near-eye display includes optics that can focus light using electronically actuated components without moving parts. This allows the near-eye display to adjust and focus according to each individual's optometry prescription. It also allows the optics to be used to focus and turn on and off a virtual image source in the near-eye display as needed, thus allowing the real world to be observed even in the absence of a virtual image. The optics can also be rapidly turned on and off to combine a virtual image with a real-world image, so that the observer perceives the virtual and real-world images as if they were observed simultaneously. Additionally, the optics can rapidly change or reposition the focal point of the lens that focuses the virtual image. This rapid change can be used to increase the apparent number of visible pixels, thereby improving / increasing resolution.

[0008] The near-eye display of the present invention may include an array of luminescent transparent pixels in optical communication with a switchable microlens array. In operation, the luminescent transparent pixel array transmits ambient light and emits light toward the eyes of a person wearing the near-eye display. The switchable microlens array focuses the light to form a virtual image perceived by the person wearing the near-eye display.

[0009] The luminescent transparent pixel array and the adjustable microlens array can be embedded in an eyeglass lens. The luminescent transparent pixel array may contain at least 100 pixels × 100 pixels, if not more. Each luminescent transparent pixel in the luminescent transparent pixel array may contain a switchable microlens. Furthermore, the switchable microlens array can switch between a focused and unfocused state at a rate of at least 60 Hz.

[0010] Each switchable microlens may be an electroactive lens that focuses the light to a focal point when the light is in a first polarization state and transmits the light without focusing it to the focal point when the light is in a second polarization state. In this case, the near-eye display may include a polarization modulator (e.g., a dynamic half-wave plate) in optical communication with the electroactive lens. The polarization modulator can switch the light from a corresponding transparent emitting pixel emitting light in the first polarization state between the first polarization state and the second polarization state at a rate of at least 60 Hz.

[0011] The near-eye display may further include an array of tilting mechanisms in optical communication with the luminescent transparent pixel array and the switchable microlens array. These tilting mechanisms can, for example, guide the light emitted by the luminescent transparent pixel array between resolvable angles at a rate of at least 60 Hz. In this case, the luminescent transparent pixel array may contain a first number of pixels, and the tilting mechanisms can guide the light sufficiently quickly between resolvable light spots so that the switchable lens array forms a virtual image with a second number of pixels greater than the first number.

[0012] Each tilting mechanism may include a polarization adjuster in optical communication with a polarization-selective beam director. The polarization adjuster switches the light from the corresponding transparent emitting pixel between a first polarization state and a second polarization state at a rate of at least 60 Hz. The polarization-selective beam director directs the light in the first polarization state along a first direction and the light in the second polarization state along a second direction. This polarization-selective beam director may be a static polarization-selective beam director (e.g., a crystal optics device or a polarizing thin-film beam splitter) or a dynamic polarization-selective beam director comprising a birefringent liquid crystal material actuated by a voltage source.

[0013] The near-eye display may also include a fixed microlens array in optical communication with the adjustable microlens array, which is used to focus the light.

[0014] Another near-eye display of the present invention includes an array of luminescent transparent pixels having a first number of pixels, a polarization-selective tilting mechanism array, and a switchable microlens array in optical communication with a polarization modulator array. In operation, the luminescent transparent pixel array transmits ambient light and emits light with a first polarization toward the eye of a person wearing the near-eye display. The polarization modulator array switches the light between the first polarization state and a second polarization state at a rate of at least 60 Hz. The polarization-selective tilting mechanism array orients the light in the first polarization state along a first direction and the light in the second polarization state along a second direction. The switchable microlens array focuses the light in the first polarization state and the light in the second polarization state to form a virtual image perceived by the person wearing the near-eye display, having a second number of pixels greater than the first number.

[0015] All combinations of the foregoing concepts and the additional concepts discussed in more detail below (provided that these concepts do not contradict each other) are contemplated as part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter appearing at the end of this disclosure are considered part of the inventive subject matter disclosed herein. Terms expressly used herein, which may also appear in any disclosure incorporated by reference, shall be given the meaning most consistent with the specific concepts disclosed herein. Attached Figure Description

[0016] Those skilled in the art will understand that the accompanying drawings are primarily for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily drawn to scale; in some cases, various aspects of the inventive subject matter disclosed herein may be exaggerated or enlarged in the drawings to aid in understanding different features. In the drawings, similar reference numerals generally refer to similar features (e.g., functionally similar and / or structurally similar elements).

[0017] Figure 1 A near-eye display is shown.

[0018] Figure 2 It shows the applicability Figure 1 The pixels and adjustable microlenses of near-eye displays.

[0019] Figure 3A and 3B Explanation Figure 2 Operation of the (first) polarization adjuster (liquid crystal waveplate).

[0020] Figure 4A and 4B Explanation Figure 2 The operation of the tilting mechanism.

[0021] Figure 5A and 5B This illustrates how the first polarization adjuster and the tilting mechanism can work together to guide light.

[0022] Figure 6A and 6B Explanation Figure 2 The operation of the switchable lens.

[0023] Figure 7A and 7B This demonstrates that the second polarization adjuster and the switchable lens can work together to focus or collimate light.

[0024] Figure 8 It shows Figure 2 The pixels and adjustable microlenses guide the collimated light in a specific way.

[0025] Figure 9 It shows Figure 2 The pixels and tunable microlenses can focus light in a way that allows for focusing.

[0026] Figure 10 It shows Figure 2 The pixels and tunable microlenses guide and focus light in a specific way.

[0027] Figure 11 An alternative near-eye display is shown, in which each pixel contains or is coupled to a Figure 6A and 6B This is similar to an adjustable lens that works in conjunction with a corresponding fixed lens. Detailed Implementation

[0028] Figure 1 An example near-eye display 10 is shown, which has transparent light-emitting pixels 5 and adjustable focusing and beam-guiding elements 7, also referred to as adjustable microlenses. This near-eye display 10 can be mounted on or embedded in an eyeglass frame (not shown), or embedded in a lens 12 with or without optical power. The lens may also include an embedded controller 14 and a power supply 16 for activating and powering the pixels 5 and the adjustable microlenses 7. The controller 14 and / or power supply 16 may also be attached to or embedded in the eyeglass frame and connected to the pixels 5 and the adjustable microlenses 7 via a wired or wireless connection.

[0029] Pixel 5 can be implemented as a transparent OLED array emitting red, green, and blue light. While the typical shape of pixels currently manufactured is rectangular or circular, it can be any other suitable shape, including those primarily limited by improved manufacturing methods. Pixel arrays arranged in a grid of two by three pixels can be used to display useful characters. Typically, near-eye displays with more pixels have a finer spatial resolution, with suitable near-eye displays having arrays of 1920 pixels by 1080 pixels. Other arrays can be many times larger than this. Pixel pitch can range from a few millimeters to hundreds of nanometers or even tens of nanometers or less.

[0030] Each pixel 5 is separated from its corresponding adjustable focusing and beam guiding element 7 by a distance 4, the adjustable focusing and beam guiding element also referred to as an adjustable microlens. Depending on the number of pixels 5, the lateral dimension of each pixel 5, and the pixel pitch, each adjustable microlens 7 may have one pixel 5 or more pixels 5. For example, if each pixel 5 emits only one color of light (e.g., red, green, or blue light), then each adjustable microlens 7 may have at least one pixel 5 emitting red light, one pixel 5 emitting green light, and one pixel 5 emitting green light. In this case, the pixels 5 may be arranged in a Bayer pattern or other suitable pattern to provide a panchromatic image. Larger pixels may be 1 mm × 1 mm. Smaller pixels may have a length or width of 6.3 micrometers or less. The spacing and lateral dimension of the microlenses may match the spacing and lateral dimension of the pixels, for example, a spacing and lateral dimension of approximately 10 nm, 100 nm, 1 μm, 10 μm, 100 μm, 1 mm, or 10 mm.

[0031] In operation, each pixel 5 emits light 6 to a corresponding adjustable microlens 7. The adjustable microlens 7 guides and / or focuses the light 6 so that the eye 8 can focus the light onto a focal point 9 on the retina. Adjusting the distance 4 between the pixel 5 and the microlens 7 changes the optical focusing degree of the lens 7 to achieve the prefocus amount required by the eye 8, thereby correctly focusing the light at the focal point 9. This adjustment of the distance 4 adapts the optics (microlens 7) to the eye 8's optometry prescription.

[0032] Figure 2The individual pixel 5 and the individual adjustable microlens 7 of the near-eye display 10 are described in more detail. The adjustable microlens 7 includes a first polarization modulator (switchable half-wave plate) 20, which is connected in series with an adjustable tilt mechanism / beam guide element 55, a second polarization modulator (switchable half-wave plate) 85, and a switchable lens 105. The first polarization modulator 20 and the second polarization modulator 85 switch the polarization state of light propagating through the adjustable microlens 7 between a first linear polarization state 15 (e.g., perpendicular to the plane of the figures / schemes) and a second linear polarization state 50 (e.g., parallel to the plane of the figures / schemes). In other forms of adjustable micropixels, the polarization modulator can switch light between other polarization states, such as linear polarization states of ±45° or left-handed and right-handed circular polarization states. The adjustable tilt mechanism / beam guide element 55 and the switchable lens 105 guide and focus light in a polarization state different from the other polarization state, respectively.

[0033] The tunable microlens 7 operates by using a polarization adjuster to switch the polarization state of the light 130 emitted by pixel 5, such that the light 130 is guided or focused by the tilting mechanism / beam guiding element 55 and the switchable lens 105, or passes through these elements unchanged. In operation, pixel 5 emits beam 130 in polarization state 15, which is perpendicular to the plane of the figure / schema (this polarization state is indicated by X, where X is the tail of an arrow representing the polarization vector pointing in the plane of the figure / schema). The light 130 enters the polarization adjuster 20 in polarization state 15 and then exits in polarization state 50. Polarization state 50 is a symbol used to identify a linear polarization direction parallel to the plane of the figure / schema, or in other words, a symbol oriented from left to right or right to left across the figure / schema.

[0034] Each pixel 5 can be implemented as an OLED emitting monochromatic (e.g., red, green, or blue) light in a first polarization state 15. Pixel 5 can also be configured to emit randomly polarized light. In this case, the light can be polarized in the first polarization state 15 using a polarization filter, or it can be allowed to pass through a randomly polarized system in which various components only affect the light in the desired polarization state to achieve the expected result and do not affect the light components in other polarization states.

[0035] Polarization switching and beam guiding elements of tunable microlenses

[0036] The first polarization modulator 20 is a half-wave plate that can switch between no delay in a first state and half-wave delay in a second state. An exemplary switching speed for this component is 30 milliseconds, but depending on the liquid crystal used, the speed can range from 5 milliseconds to 300 milliseconds. The first polarization modulator 20 is composed of a first substrate 25 and a second substrate 30, wherein a liquid crystal layer 27 (e.g., Merck MLC-2140) is sandwiched and sealed between the two substrates 25 and 30. On the surface of the first substrate 25 is a first electrode 40, which is composed of a transparent conductive coating (e.g., tin oxide (ITO)), and above the ITO is a first transparent alignment layer (not shown; e.g., polyimide made of Nissan Sunever 410 polyimide varnish). The first alignment layer is typically applied, cured, and then rubbed with a felt cloth in the direction of the desired alignment orientation of the liquid crystal. Adjacent to the first electrode 40 is the liquid crystal 27.

[0037] A second electrode 35, made of a transparent conductive material (e.g., ITO), is located on the surface of the second substrate 30. A second alignment layer is present on the second electrode 35. The first and second alignment layers are rubbed or oriented to align the liquid crystal molecules in orthogonal directions. Figure 2 In the example shown, the first alignment layer is configured to be oriented parallel to the adjacent liquid crystal molecules 27 in the second polarization state 50 (parallel to the plane of the page), while the second alignment layer is configured to be oriented parallel to the adjacent liquid crystal molecules in the first polarization state 15 (perpendicular to the plane of the page). When viewed along the optical axis of the tunable microlens, these alignment layers appear to be in an intersecting state, the optical axis being perpendicular to both the first and second polarization states.

[0038] This cross-alignment layer configuration causes the liquid crystal molecules to exhibit a twisted configuration 45 when no applied voltage is applied. That is, when relaxed, the liquid crystal molecules align in orientation 50 near the first substrate 25, in orientation 15 near the second substrate 30, and in the middle of the liquid crystal layer at the midpoint between orientations 50 and 15. The closer the liquid crystal is to the first electrode 40 and the second electrode 35, the more the liquid crystal molecules twist in the directions closer to orientations 50 and 15. When the liquid crystal 27 is in the twisted configuration 45, the first polarization modulator 20 changes the polarization state of the incident light 130 from the first polarization state 15 to the second polarization state 50. Applying a voltage to the first electrode 40 and the second electrode 35 causes the liquid crystal 27 to unfold (straighten). When the liquid crystal 27 is unfolded, the light 130 propagating through the first polarization modulator 20 remains in the first polarization state 15.

[0039] Figure 3A and 3B The first polarization modulator 20 is shown in both the off and on states. Figure 3A A voltage source 145 connected to electrodes 35 and 40 is shown. When this voltage source 145 is turned off, the liquid crystal 27 is in a twist orientation 45. This is referred to as the "off state". Figure 3B In this state, voltage source 145 is turned on, causing liquid crystal 27 to be reoriented into straightening or spreading orientation 135, wherein the liquid crystal molecules are aligned perpendicularly to substrates 35 and 40 of the first polarization adjuster 20. This is referred to as the "on state".

[0040] Refer again Figure 2 The tilting mechanism 55 consists of two wedge-shaped structures 60 and 65. The first structure 60 may be made of a solid material, such as glass, while the second structure 65 may be made of a solid birefringent material, such as quartz, or a cavity containing an adjustable birefringent material, such as liquid crystal. (In these cases, the tilting mechanism 55 may be implemented as a Glan-Thompson polarizer, a Rochon prism, a Wollaston prism, a calcite beam displacer, or other suitable crystal polarizer.) If the second structure 65 is made of a solid birefringent material, the solid birefringent material is oriented such that its refractive index along the second polarization direction 50 matches the refractive index of the first structure 60, while its refractive index along the first polarization direction 15 differs from the refractive index of the first structure 60. The operation of the static tilting mechanism 55 is controlled by a first polarization adjuster 20. When the polarization rotates in one direction, no tilting is introduced. When the polarization rotates in the other direction, tilting occurs. Therefore, the speed of this component is the same as the speed of the polarization adjuster. This is the preferred embodiment.

[0041] In an alternative embodiment, the second structure 65 may be configured as a sealed cavity containing an electrically actuated birefringent liquid, such as a liquid crystal material. In this case, a third substrate 70 may be added to provide one boundary of the cavity. One side of the first structure 60 provides the other boundary of the cavity. A side-sealing structure (not shown) seals the liquid crystal within the cavity.

[0042] In this configuration, transparent electrodes 75 and 80 are located on opposite sides of the cavities (e.g., on the surfaces defining the cavities of the first structure 60 and the third structure 70). These electrodes 75 and 80 perform the same function as electrodes 35 and 40 in the first polarization modulator 20. Without voltage applied to electrodes 75 and 80, the liquid crystal is oriented to match the refractive index of the first structure 60. In this state, light 130 passes through the tilting mechanism 55, and its propagation direction or polarization state is unaffected. Applying voltage to electrodes 75 and 80 redirects the liquid crystal so that its refractive index no longer matches the refractive index of the first structure 60. Therefore, light 130 passing through the tilting mechanism 55 is refracted at the boundary between the first structure 60 and the second structure 65. This refraction guides light 130 without altering its polarization state.

[0043] Figure 4A and 4B A liquid crystal tilting mechanism 55 is shown, in which a voltage source 150 is connected to electrodes 75 and 80. Figure 4A The tilting mechanism is shown when the voltage source 150 is off, and Figure 4B The tilting mechanism when the voltage source 150 is turned on is shown. When the voltage source 150 is turned off, the light 140 in the second polarization state 50 experiences the same refractive index in both the liquid crystal 65 and the first structure 60, so no optical effect (tilting or guiding) occurs. When the voltage source 150 is turned on, the liquid crystal 65 reorients itself to form a refractive index mismatch for the light 155 in the second polarization state 50 at the boundary between the liquid crystal 65 and the first structure 60. This causes the beam 155 to tilt at the boundary, as... Figure 4B As shown. The tilt angle is large enough to produce a light spot that is distinguishable from the light spot produced when the tilt mechanism is closed (i.e., the tilt angle is distinguishable, just like the corresponding light spots formed by tilted and untilted beams in a virtual image plane). The beam 155 is refracted again as it leaves the first structure 60 and enters free space.

[0044] Figure 4B The tilting mechanism 55 is shown operating independently, without any other components attached. However, in a preferred embodiment, the tilting mechanism 55 is directly engaged with another component having the same refractive index. Since the refractive index does not change at this interface, the outgoing light beam should not refract as it exits the tilting mechanism 55.

[0045] The tilting of light occurs only in one polarization direction (here, the second polarization state 50). Regardless of whether the voltage source 140 is on or off, incident light in an orthogonally polarized state (first polarization state 15) propagates through the tilting mechanism 55 without bending or tilting.

[0046] If the liquid crystal in the cavity type of the tilting mechanism 55 is a planar liquid crystal (rather than a vertically aligned liquid crystal), the amount of change in the refractive index of the liquid crystal can be controlled by applying a voltage in an analog manner, thus making the tilting mechanism 55 an analog adjustable device. An example liquid crystal is the Merck MLC-2140, which responds to voltage changes, with the maximum fluctuation typically between 0.5 volts and 8 volts. The voltage is typically an alternating current (AC) sine wave or square wave, with a frequency typically between 15 Hz and 60 Hz. Lower frequencies can be used, but flicker may become visible. Higher frequencies can be used, but then power consumption increases.

[0047] Figure 5A and 5BIt is shown that the tilting mechanism 55 and the first polarization adjuster 20 can work together to select the method of tilting or guiding light. When the first polarization adjuster 20 is in Figure 5A When in the off state as shown, tilting will not occur regardless of whether the liquid crystal in the tilting mechanism 55 is in the on or off state. When both the first polarization adjuster 20 and the tilting mechanism 55 are in the off state... Figure 5B When the switch is activated, tilting occurs. Because the liquid crystal layer 27 in the polarization switcher 20 is much thinner than the liquid crystal layer in the tilting mechanism 55, the switching speed of the first polarization adjuster 20 is much faster than that of the tilting mechanism 55. This makes the tilting function of the tilting mechanism open and close faster than the switching speed of the tilting mechanism 55 itself.

[0048] If the tilting mechanism 55 is made of a solid birefringent material instead of a birefringent liquid crystal, the tilt amount provided by the tilting mechanism may not be adjustable, but it can still be quickly turned on and off using the first polarization adjuster 20. This is a preferred embodiment.

[0049] Two or more tilting mechanisms 55 (and polarization adjusters 20, if desired) can be coupled in series or stacked with tilt orientations at different angles to each other, thereby allowing tilting in more than one direction. For example, as Figure 5A and 5B The tilting mechanism shown, stacked on top of another tilting mechanism rotated 90° around the light (z) axis, can produce four different beam guiding or tiling angles: relative to Figure 5A and 5B The two left-to-right corners of the plane and the two "in-out" corners.

[0050] Polarization switching and focusing elements of tunable microlenses

[0051] Refer again Figure 2 Light emitted from the tilting mechanism 55 enters the second polarization modulator 85. Similar to the first polarization modulator, the second polarization modulator 85 can be a half-wave plate, which can switch between no delay in the first state and half-wave delay in the second state. When no power is applied to the second polarization modulator 85, the liquid crystal is in the twisted configuration 90 (same as configuration 45), and when power is applied, the liquid crystal is in the unfolded configuration. In the twisted (closed) configuration 90, the second polarization modulator 85 converts light in the first polarization state 15 to the second polarization state 50. And in the unfolded (on) configuration, light in the first polarization state 15 propagates through the second polarization modulator 85 without changing its state.

[0052] like Figure 2As shown, light emitted from the second polarizer 85 enters a switchable lens 105, which is composed of a solid component 115 with a concave surface joined together to form a sealed cavity 100 and a planar substrate 110. A first electrode 120 is present on the concave surface, while a second electrode 125 facing the concave surface is present on the surface of the planar substrate 110. These electrodes 120 and 125 are transparent and coated with alignment layers having parallel or antiparallel rubbing / alignment directions. (The alignment layers in the polarizer are rubbed in directions orthogonal to each other, while the alignment layers in other components are typically rubbed parallel or antiparallel to each other.) The cavity contains a volume of liquid crystal, whose birefringence is oriented to match the refractive index of structure 115 when no voltage is applied across electrodes 120 and 125. In this closed state, light passes through lens 105, and its propagation direction is unaffected by polarization. Applying a voltage to electrodes 120 and 125 causes the liquid crystal molecules to reorient themselves. This reorientation increases the apparent refractive index of the liquid crystal material, thereby focusing the light passing through the switchable lens 105.

[0053] Switchable lenses can have on-state focal lengths ranging from as low as 1 mm to as high as 25 mm. The on-state focal length can be switched rapidly to 3 milliseconds or slowly to 300 milliseconds, depending on the liquid crystal and lens size used. The optical power of the lens can be simply on / off, or can be analog-adjusted within a certain range. Smaller lenses (e.g., 1 mm in diameter) typically switch faster than larger lenses (e.g., 3 mm in diameter), and liquid crystals with lower rotational viscosity typically switch faster than those with higher rotational viscosity.

[0054] Cavity 100 may also be constructed from similarly oriented solids and / or non-adjustable birefringent materials. In this case, the switchable lens 105 can operate as a binary on / off assembly. Similarly, the planar substrate 110 may be replaced with a substrate having another concave or convex surface to form a cavity in the shape of a biconvex or convex-concave lens. The substrate surface may also be patterned in the shape of a Fresnel, diffractive, or stepped surface.

[0055] Figure 6A and 6B A voltage source 160 is shown connected to a switchable lens 105 of electrodes 120 and 125. Cavity 100 is filled with liquid crystal. When the voltage source 160 is off, light 165 passes through cavity 100 (and switchable lens 105) without optical effects. This is because, for light polarized in a first polarization state 15, the refractive index of the liquid crystal along the optical axis of the switchable lens is the same as the refractive index of element 115. This is Figure 6AThe state is shown. When voltage source 160 is turned on and a voltage is applied to electrodes 120 and 125, the liquid crystal in cavity 100 aligns with the applied electric field. This changes the refractive index of the liquid crystal along the optical axis of the switchable lens, causing light polarized in the first polarization state 15 to be focused, for example, at focal point 170. Due to the birefringence of the liquid crystal, even when voltage source 160 is turned on, switchable lens 105 will not focus light in the second polarization state 50.

[0056] If a flat-panel liquid crystal is used, such as the Merck-MLC-2140, the refractive index can be adjusted analogously, thus allowing the position of the focal point 170 to be adjusted analogously. This makes it possible to adjust the position of the focal point 170 without adjusting... Figure 1 The focal length of the adjustable microlens 7 is adjusted when the distance between the adjustable microlens 7 and the pixel 5 is 4.

[0057] For the switchable lens 105 to focus incident light, the polarization of the light should be aligned with the friction direction of the alignment layer of the switchable lens, which in this example is parallel or antiparallel to the first polarization state 15. In some cases, depending on the state of earlier components in the optical path, the light arriving at the point of entry of lens 105 may be in a second polarization state 50. In these cases, if the beam is to be focused, the second polarization adjuster 85 switches the incident light from the second polarization state 50 to the first polarization state 15, thus enabling the switchable lens 105 to focus the beam. Similarly, if the light incident on the second polarization adjuster 85 is in the first polarization state 15 and the second polarization adjuster 85 is off, the light is directed in an undesirable orientation (i.e., as...). Figure 3A The light (in the second polarization state 50) exits from the second polarization adjuster 85. In these cases, the second polarization adjuster 85 should be turned on to ensure that the light reaching the switchable lens 105 is in the first polarization state 15.

[0058] Figure 7A and 7B The operation of a switchable lens 105 connected in series with a second polarization adjuster 85 (which is connected and controlled, and operates in the same manner as the first polarization adjuster 20) is shown. Figure 7A In this configuration, the incident light is in a second polarization state 50, the second polarization adjuster 85 is closed, and the switchable lens 105 is activated. The second polarization adjuster 85 changes the incident light from the second polarization state 50 to the first polarization state 15, and the switchable lens 105 focuses the light to the focal point 170. Figure 7B In this configuration, the incident light is in a first polarization state 15, the second polarization adjuster 85 is activated, and the switchable lens 105 is activated. The incident light propagates through the second polarization adjuster 85 without changing its polarization state, and is focused to the focal point 170 by the switchable lens 105.

[0059] The second polarization modulator 85 switches states (i.e., on and off) faster than the switchable lens 105, thus allowing it to be used as a faster on / off switch for the optical power of the switchable lens 105. The switchable lens 105 can be adjusted to the desired optical power and then switched on and off by the faster second polarization modulator 85, even if the switchable lens 105 remains on. Alternatively, the liquid crystal within the lens cavity 100 can be a cholesteric liquid crystal, thereby eliminating the polarization aspect of the system and the second polarization modulator 85 and making the lens a binary switchable on / off optics device.

[0060] Figure 7A A filter 175 is also shown on the surface of the second polarizer 85 closest to the switchable lens 105. A photoactivated curable polymer and / or monomer can be added to the liquid crystal in the cavity 100, allowing the optical power of the switchable lens to be frozen or fixed after it has been adjusted to the user's prescription. If the liquid crystal in the polarizer should not be frozen or fixed during the lens curing process, the passband of the filter 175 can be selected to prevent the photoactivated / curing wavelength used to cure the polymer in the lens cavity 100 from reaching the second polarizer 85. This method can be used to fit a near-eye display to a specific person's eye prescription and then freeze it in place to simplify the system. If no photosensitive polymer is used in the polarizer and the liquid crystal used is UV stable, the filter 175 is not required.

[0061] Guide and / or focus light using a near-eye display

[0062] Figure 8-10 The operation of the pixel 5 and the entire adjustable microlens 7 in the near-eye display 10 with a static tilt mechanism 55 is explained. Figure 8 The diagram illustrates a system in which the first polarization adjuster 20 is configured to tilt the light using the tilting mechanism 55 and with the lens 105 in the closed state. The system tilts the light but does not focus it. Figure 9 The system shown is configured such that the tilting mechanism 55 transmits light without tilting the light and the lens 105 is in the on state. Figure 10 The diagram shows the first polarization adjuster 20 configured such that the tilt mechanism 55 tilts the light from pixel 5 and the lens 105 is in the on state. The light is tilted and focused.

[0063] Table 1 is a truth table that shows whether the adjustable microlens 7 bends or focuses light from the pixel 5 for different combinations of settings of the first polarizer 20, the second polarizer 85, and the switchable lens 105 with a static tilt mechanism 55.

[0064]

[0065]

[0066] Table 1: Truth Table for Adjustable Microlens Assembly Settings

[0067] In some of the example component states described above, light passes through the tunable microlens 7 without focusing or tilting. This can be described as the "fully closed state" of the tunable microlens. This state can be used under conditions necessary to allow the user to see real-world objects beyond the pixel 5 / near-eye display 10.

[0068] Although the components are shown as being separated to improve Figure 9 The clarity is good, but they can be joined together with no air interface in between (therefore almost no refraction), such as Figure 8 and 10 As shown. In other words, the components can be integrated into a single optical block without any moving parts. Compared to discrete components, this optical block is more robust and less susceptible to vibration. If the components are made of a material with a low coefficient of thermal expansion, the optical block may also be less susceptible to temperature fluctuations.

[0069] Near-eye display with adjustable and fixed microlenses

[0070] Figure 11 An alternative near-eye display 11 is shown, featuring an adjustable microlens 7 that operates in conjunction with a corresponding fixed lens 3. The fixed lens 3 can be a conventional lens made of glass or plastic and formed together in the microlens array. The fixed lens 7 allows for a narrower adjustment range of the adjustable microlens 7, enabling the use of thinner, faster-switching liquid crystal layers in the polarizer, tilt mechanism, and switchable lens of the adjustable microlens 7. For example, if the required total adjustment range is from 300 diopters to 500 diopters of optical power, the fixed lens 3 can have an optical power of 300 diopters, and the adjustable microlens 7 can have an adjustment range of 0 diopters to 200 diopters instead of 0 diopters to 500 diopters.

[0071] exist Figure 1 Near-eye monitor 10 and Figure 11 In the near-eye display 11, both pixels 5 and tunable microlenses 7 are shown as full features, meaning they can achieve pixel emission, polarization adjustment, tilting, and focus changes. In operation, not all features may be needed simultaneously. In these cases, only the parts required to achieve the desired goal can be included in the deployed system, while others can be omitted.

[0072] The flat and concave surfaces and orientations of the liquid crystal molecules described above and illustrated in the accompanying drawings, as well as the birefringence, are merely examples; alternatively, other substrate / lens shapes and liquid crystal orientations can be used to achieve the desired light bending and focusing. This focusing can occur in different directions, such as diverging rather than converging. Similarly, the tilting mechanism 55 can be arranged to tilt the light to the left rather than the right, and the polarization adjusters 20 and 85 can be changed or arranged to switch the polarization of the incident light from the second polarization state 50 to the first polarization state 15, rather than switching it from the first polarization state to the second polarization state, etc.

[0073] Although the adjustable lens described above uses liquid crystal as the material for modifying the refractive index of certain layers, other materials with changeable refractive indices can be used, including lithium niobate (LiNbO3), barium titanate (BaTiO3), lithium tantalate (LiTaO3), and many other materials.

[0074] Beam guidance to increase apparent near-eye display resolution

[0075] The rapid tilting or beam guiding provided by the adjustable microlens 7 can be used to increase the apparent spatial resolution of the near-eye displays 10 and 11. By switching the focus of each microlens between a pair of resolvable light spots at a frequency faster than the flicker fusion threshold frequency, a resolution higher than the display resolution can be perceived by the user. The flicker fusion threshold frequency is the frequency at which intermittent light stimulation appears completely stable to the average human observer. The flicker fusion threshold frequency depends on several factors but is typically between 15 Hz and 60 Hz.

[0076] Due to the rapid switching rate of the first polarization modulator 20 and the second polarization modulator 85, the tunable microlens 7 can guide and focus light from pixel 5 back and forth between two points at a rate exceeding the flicker fusion threshold. This allows a person wearing near-eye displays 10, 11 to perceive two distinct pixels, even though there is actually only one pixel. If the tunable microlens 7 switches the light from pixel 5 between these two locations with a 50% duty cycle, each of the two apparent pixels should be displayed at half the brightness of the actual pixel 5.

[0077] This beam guiding and focusing can be used to double or quadruple the number of apparent pixels in near-eye displays 10, 11. For example, if near-eye displays 10, 11 have a 100-pixel × 100-pixel array, each array having as... Figure 2The corresponding adjustable microlens 7 shown can increase the apparent resolution of the near-eye display to 200 pixels × 100 pixels. If a second tilting mechanism 55 is added to each adjustable microlens 7 to tilt the light beam in orthogonal directions (e.g., in addition to the left- and right-switching provided by the first tilting mechanism 55, there is also an up- and down-switching), the light from each pixel 5 can be shifted in both directions. This makes it possible to project four apparent pixels from a single pixel. Therefore, the 100-pixel × 100-pixel near-eye displays 10 and 11 can be considered as 200-pixel × 200-pixel displays.

[0078] The adjustable microlens 7 can also switch between focused and unfocused states using a second polarization adjuster 85 at a speed faster than the flicker fusion threshold frequency. By "turning off" the switchable lens 105 using the second polarization adjuster 85 at a speed faster than the flicker fusion threshold frequency, the corresponding pixel 5 and ambient light overlap for the wearer of the near-eye displays 10 and 11. In other words, it causes the virtual image from pixel 5 and the real image to appear simultaneously. The wearer sees two rapidly alternating, continuous views, one of the virtual image and the other of the real-world image, thus providing the wearer with the illusion of a virtual image superimposed on a real-world image. Adjusting the brightness of pixel 5 or the duty cycle of the second polarization adjuster 85 changes the apparent brightness of the virtual image. (Alternatively, the same effect can be achieved by simply turning pixel 5 on and off at a speed faster than the flicker fusion threshold frequency.)

[0079] Conclusion

[0080] Although various embodiments of the invention have been described and illustrated herein, those skilled in the art will readily conceive of a variety of other means and / or structures for performing functions and / or obtaining results and / or one or more advantages described herein, and each of such variations and / or modifications is considered to be within the scope of the embodiments of the invention described herein. More generally, those skilled in the art will readily understand that all parameters, dimensions, materials, and configurations described herein are exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on one or more specific applications for which the invention is taught. Those skilled in the art can recognize or determine many equivalents of the particular inventive embodiments described herein using at most conventional experimentation. Therefore, it should be understood that the foregoing embodiments are given by way of example only, and embodiments of the invention may be practiced in ways other than those specifically described and claimed within the scope of the appended claims and their equivalents. The inventive embodiments of this disclosure relate to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods (if such features, systems, articles, materials, kits, and / or methods are not inconsistent with each other) is included within the inventive scope of this disclosure.

[0081] The above embodiments can be implemented in any of a variety of ways. For example, embodiments of the techniques disclosed herein can be implemented using hardware, software, or a combination thereof. When implemented in software, the software code can be executed on any suitable processor or set of processors, whether set up in a single computer or distributed across multiple computers.

[0082] Furthermore, various inventive concepts can be embodied in one or more methods, examples of which have been provided. Actions performed as part of a method can be ordered in any suitable manner. Therefore, embodiments can be constructed that perform actions in an order different from that described, which may include the simultaneous execution of some actions, even those shown as sequential in the illustrative embodiments.

[0083] It should be understood that all definitions defined and used herein take precedence over dictionary definitions, definitions in referenced documents, and / or the general meaning of the terms used in the definitions.

[0084] As used herein in the specification and claims, the indefinite article “a” should be understood to mean “at least one” unless explicitly indicated to the contrary.

[0085] As used herein in the specification and claims, the phrase “and / or” should be understood to mean “any one or two” of the elements so combined, that is, the elements exist together in some cases and separately in others. Multiple elements listed with “and / or” should be interpreted in the same way, that is, “one or more” of the elements so combined. In addition to the elements specifically indicated by the “and / or” clause, other elements may optionally be present, whether related to or unrelated to those specifically indicated. Thus, as a non-limiting example, when used in conjunction with open-ended language (e.g., “comprising”), reference to “A and / or B” may in one embodiment refer only to A (optionally including elements other than B); in another embodiment only to B (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); and so on.

[0086] As used herein in this specification and claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when multiple items are separated in a list, “or” or “and / or” will be interpreted as inclusive, that is, including at least one, but also including several elements or more than one element in a list of elements and optionally additional unlisted items. Only terms that explicitly indicate the opposite, such as “only one of…” or “exactly one of…” or “consisting of…” when used in claims, will refer to including multiple elements or exactly one element in a list of elements. Generally, the term “or” as used herein should only be interpreted as indicating an exclusive alternative (i.e., “one or the other, but not both”) before exclusive terms such as “any one,” “one,” “only one,” or “exactly one”. “Substantially consisting of…” when used in claims should have the ordinary meaning as it is used in the field of patent law.

[0087] As used herein in the specification and claims, when referring to a list of one or more elements, the phrase "at least one" should be understood to mean at least one element selected from any one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements referred to by the phrase "at least one," regardless of whether they are related to those specifically identified elements. Thus, as a non-limiting example, in one embodiment, "at least one of A and B" (or, equivalently, "at least one of A or B," or equivalently, "at least one of A and / or B") may refer to at least one, optionally including more than one A, without B (and optionally including elements other than B); in another embodiment, it may refer to at least one, optionally including more than one B, without A (and optionally including elements other than A); in yet another embodiment, it may refer to at least one, optionally including more than one A, and at least one, optionally including more than one B (and optionally including other elements); etc.

[0088] In the claims and in the foregoing description, all conjunctions such as “comprising,” “including,” “with,” “having,” “containing,” “involving,” “accommodating,” “constituting,” and “composed of” should be understood as open-ended, meaning that they include but are not limited to. As described in Section 2111.03 of the U.S. Patent Examination Procedure Manual, only the transitional phrases “composed of” and “substantially composed of” should be closed or semi-closed transitional phrases, respectively.

Claims

1. A near-eye display, comprising: An array of luminescent transparent pixels that transmits ambient light and emits light toward the eyes of the person wearing the near-eye display; as well as A switchable microlens array, optically in communication with the luminescent transparent pixel array, for focusing the light to form a virtual image perceived by a person wearing the near-eye display, the switchable microlens array comprising: The liquid crystal lens, which is optically in communication with the corresponding transparent light-emitting pixels in the light-emitting transparent pixel array, is capable of switching between a focused state and an unfocused state. In the focused state, the liquid crystal lens focuses the light to a focal point when the light is in a first polarization state and transmits the light in a second polarization state without focusing the light in the second polarization state. In the unfocused state, the liquid crystal lens transmits the light in both the first and second polarization states without focusing the light in either the first or second polarization state. as well as A polarization modulator, located between the corresponding transparent light-emitting pixel and the liquid crystal lens, is capable of switching between a first state and a second state, which is faster than the liquid crystal lens switching between the focused state and the unfocused state. In the first state, the polarization modulator switches the light from the first polarization state to the second polarization state. In the second state, the light in the first polarization state propagates through the polarization modulator without changing its polarization state.

2. The near-eye display according to claim 1, wherein the light-emitting transparent pixel array and the switchable microlens array are embedded in the spectacle lens.

3. The near-eye display according to claim 1, wherein the light-emitting transparent pixel array is at least 100 pixels by 100 pixels.

4. The near-eye display according to claim 1, wherein each transparent light-emitting pixel in the light-emitting transparent pixel array has a switchable microlens.

5. The near-eye display of claim 1, wherein the switchable microlens array is configured to switch between the focused state and the unfocused state at a rate of at least 60 Hz.

6. The near-eye display of claim 1, wherein the polarization modulator is configured to switch the light from the corresponding transparent light-emitting pixel between the first polarization state and the second polarization state at a rate of at least 60 Hz.

7. The near-eye display of claim 1, wherein the light-emitting transparent pixel array is configured to emit the light in the first polarization state.

8. The near-eye display according to claim 1, further comprising: An array of tilting mechanisms that optically communicates with the luminescent transparent pixel array and the switchable microlens array, for guiding the light emitted by the luminescent transparent pixel array between resolvable angles.

9. The near-eye display of claim 8, wherein the switchable microlens array is configured to guide light from the luminescent transparent pixel array between resolvable light spots at a rate of at least 60 Hz.

10. The near-eye display of claim 9, wherein the luminescent transparent pixel array comprises a first number of pixels, and the tilting mechanism array is configured to guide the light sufficiently quickly between the resolvable light spots so that the switchable microlens array forms the virtual image having a second number of pixels greater than the first number of pixels.

11. The near-eye display of claim 8, wherein the polarization adjuster is a first polarization adjuster and the tilting mechanism array comprises: A second polarization modulator is used to switch the light from a corresponding transparent light-emitting pixel in the light-emitting transparent pixel array between a first polarization state and a second polarization state at a rate of at least 60 Hz. as well as A polarization-selective beam director in optical communication with the polarization modulator, used to orient the light in the first polarization state along a first direction and to orient the light in the second polarization state along a second direction.

12. The near-eye display according to claim 11, wherein the polarization-selective beam director is a static polarization-selective beam director.

13. The near-eye display of claim 11, wherein the polarization-selective beam directionaler is a dynamic polarization-selective beam directionaler comprising a birefringent liquid crystal material actuated by a voltage source.

14. The near-eye display according to claim 1, further comprising: A fixed microlens array that is in optical communication with the switchable microlens array and is used to focus the light.

15. A method of operating a near-eye display, the near-eye display comprising an array of luminescent transparent pixels in optical communication with a switchable microlens array, the switchable microlens array comprising a polarization modulator and a liquid crystal lens, the liquid crystal lens focusing light in a first polarization state and transmitting light in a second polarization state without focusing light in the second polarization state, the method comprising: Light is emitted from the luminescent transparent pixel array toward the eyes of the person wearing the near-eye display; Ambient light is transmitted toward the eyes of the person wearing the near-eye display through the luminescent transparent pixel array; as well as The switchable microlens array switches between a focused state and an unfocused state in the following manner: In the focused state, the switchable microlens array focuses the light to form a virtual image perceived by a person wearing the near-eye display; in the unfocused state, the switchable microlens array does not focus the light. The polarization modulator is switched between a first state and a second state. In the first state, the polarization modulator switches the light from the first polarization state to the second polarization state. In the second state, the light in the first polarization state propagates through the polarization modulator without changing its polarization state.

16. The method of claim 15, wherein switching the switchable microlens array between the focused state and the unfocused state comprises switching the polarization modulator between the first state and the second state at a rate of at least 60 Hz.

17. The method of claim 16, wherein switching the switchable microlens array between the focused state and the unfocused state further comprises: When the light is in the first polarization state, the light is focused to a focal point; as well as The light is transmitted without being focused to the focal point when it is in the second polarization state.

18. The method of claim 17, further comprising: The polarization modulator switches between the first and second states faster than the liquid crystal lens changes state.

19. The method of claim 17, wherein emitting the light from the light-emitting transparent pixel array comprises emitting the light in the first polarization state.

20. The method of claim 15, further comprising: The light emitted by the luminescent transparent pixel array is guided at a rate of at least 60 Hz between resolvable angles.

21. The method of claim 15, wherein the luminescent transparent pixel array comprises a first number of pixels, and the method further comprises: The light emitted by the luminescent transparent pixel array is guided to form the virtual image having a second number of pixels, which is greater than the first number of pixels.

22. A near-eye display, comprising: An array of luminescent transparent pixels having a first number of pixels, which transmits ambient light and emits light toward the eyes of a person wearing the near-eye display with a first polarization; A liquid crystal polarization modulator in optical communication with the light-emitting transparent pixel array has a sufficiently thin liquid crystal layer to switch the light between a first polarization state and a second polarization state at a rate of at least 60 Hz. A polarization-selective liquid crystal tilting mechanism array that is optically in communication with the liquid crystal polarizer has a corresponding liquid crystal layer that is thicker than the liquid crystal layer of the liquid crystal polarizer, for orienting the light in the first polarization state along a first direction and for orienting the light in the second polarization state along a second direction. as well as A switchable microlens array optically communicates with the light-emitting transparent pixel array, which is used to focus the light in the first polarization state and transmit the light in the second polarization state without focusing the light in the second polarization state, so as to form a virtual image perceptible to the person wearing the near-eye display having a second number of pixels, which is greater than the first number of pixels.

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