Eyeglasses display system that uses an aperture scanner to display a virtual image within the user's field of vision

Abstract

This invention relates to an eyeglass display system (1) for displaying a virtual image within a user's field of vision, comprising: a display unit (14) for emitting light (163'', 161'', 162'') as computer-generated image information along an emission direction; and a deflection unit (17) for deflecting the light (163'', 161'', 162'') into the user's eye (10), and including a plurality of micromirror elements (12, 12', 12''), each of which is tiltable within a support structure and includes elements for redirecting the light (163'', 161''). The reflective surface (25) of the display unit (14) and the tiltable micromirror elements (12, 12', 12'') is adjusted by a control signal and configured to adjust at least one beam position (70b', 70b'', 70b*) of the light reflected at the reflective surface (25) of the tiltable micromirror elements (12, 12', 12'') according to the control signal, thereby providing a glasses display system (1) with enhanced immersion.

Description

Technical Field

[0001] This disclosure relates to an eyeglass display system for displaying a virtual image within a user's field of vision. The system includes: a display unit for emitting light as computer-generated image information along an emission direction; and a deflection unit for deflecting the light emitted by the display unit as computer-generated image information into the user's eye. The deflection unit includes a plurality of micromirror elements, each of which is tiltable within a support structure and has a reflective surface for redirecting the light emitted by the display unit as computer-generated image information. Background Technology

[0002] Eyeglasses used to display virtual images within a user's field of vision are called "augmented reality glasses" or "AR glasses." They superimpose virtual objects, presented as virtual images, onto the user's natural environment, thus virtually enhancing their field of vision. By displaying stereoscopic images, these virtual objects can be freely placed in space. Therefore, achieving the largest possible augmented field of vision and high (angular) resolution is advantageous to create immersion through the continuous visibility and spatial consistency of virtual objects—making them appear as real objects. The weight of these glasses also significantly impacts the immersive experience, especially when the head rotates, potentially causing an unnatural feeling for the user. Furthermore, the so-called convergence-accommodation conflict is a well-known effect that diminishes immersion.

[0003] Convergence-accommodation conflict exists in all 3D displays that use two stereoscopic images to display 3D objects. The 3D information, i.e., the distance between the object and the eye, is determined by the stereoscopic image, which exhibits parallax shift. However, this distance conflicts with the focusing distance required for the eye to see the image clearly. In AR applications, a related problem arises when virtual 3D objects are integrated into a real 3D environment. If the focal length of the stereoscopic image does not match the focal length of the real environment, it is impossible to view both scenes simultaneously, even if the real and virtual scenes are spatially fixed in the same position within the environment.

[0004] According to existing technology, various optical methods are known to project virtual images into the field of vision of the natural environment. However, how to make the required optical system small enough to achieve the size and weight of ordinary glasses remains a technically unsolved problem. Excessive size of glasses presents technical limitations in terms of potential applications; for example, people would not want to wear such bulky devices in their daily lives. Excessive weight means that AR glasses can only be worn for a limited time. Exemplary solutions are described in DE 10 2020 206392 A1 or DE 10 2023 101 777 A1.

[0005] US Patent 10,623,707 B2 describes an AR glasses system that provides high-resolution images for the central field of vision (fovea) and projects low-resolution image areas into the peripheral field of vision. To this end, an eye-tracking sensor is used to measure the eye's gaze and adjust the projector's optical system accordingly.

[0006] Publications US 2020 0186761 A1 and US 11 422 274 B2 describe AR glasses that allow adjustment of the focal length of an AR optical system to display objects at different distances, thereby disclosing a technical solution to resolve the convergence-accommodation conflict. US 2020 0186761 A1 also includes an eye-tracking module for measuring the convergence parameters of the eye. Furthermore, it proposes using these measurements to track the position of the optical system relative to the eye, thereby enabling eye tracking at different eye positions.

[0007] This presents the following technical challenges: to provide an immersive glasses display system that is extremely lightweight, has the widest possible virtual augmented field of view, and the best possible image quality, while also addressing common problems with AR glasses, such as convergence-accommodation conflict and / or vision correction issues. Summary of the Invention

[0008] The aforementioned problems are solved by the subject matter in the independent claims. Advantageous embodiments are disclosed in the dependent claims, the specification, and the drawings.

[0009] One aspect relates to an eyeglass display system for displaying a virtual image within a user's field of vision, the system comprising: a display unit for emitting light as computer-generated image information along an emission direction; and a deflection unit for deflecting the light emitted by the display unit as computer-generated image information into the user's eye. The emission direction preferably extends at least substantially along the user's field of vision (forward; thus the light is emitted into the field of vision), and the deflection unit is arranged within the user's field of vision (in front of the user's monocular or binocular eyes) using at least a micromirror element, and is used to deflect the light back (rearward) into the user's monocular or binocular eyes.

[0010] The deflection unit comprises multiple tiltable micromirror elements, each arranged within a support structure, and each micromirror element has a reflective surface for deflecting light emitted by the display unit as computer-generated image information into the user's eye. The reflective surface is transparent to ambient light from the environment within the user's field of vision that is directed towards the eye. Therefore, the reflective surface can be considered a translucent mirror. Accordingly, the micromirror element may also have multiple mirrors. This is the case, for example, when each micromirror element comprises a coated substrate, particularly a glass substrate. In this case, for example, one side of the substrate may be coated, while the opposite side may be uncoated. Therefore, two reflections may occur, with one side acting as a reflective surface and the opposite side acting as another reflective surface.

[0011] Reflections on the coated side can be technically adjusted as needed through a suitable coating (designed for the desired optical effect), while reflections on the uncoated side are based on Fresnel reflections arising from the change in refractive index between the substrate and its surrounding environment (e.g., the liquid within the housing element mentioned below). For micromirrors immersed in a liquid, the latter type of reflection is typically very weak because the refractive index of the typical glass used as the substrate is quite close to that of the liquid. Alternatively, the opposite side of the substrate can also have a coating. For example, this could be a stress-compensating coating, which, unlike the coating designed for the optical effect, is used to compensate for stresses generated between the substrate and the coating on one side, which could cause the substrate to warp. Technically adjusted reflective surfaces can also be located within the volume of the micromirror element, potentially resulting in a total of three reflective surfaces. In this case, two additional reflections occur at the interface between the micromirror element and its surrounding environment (ideally a liquid). These additional reflections can be of a secondary nature, i.e., significantly weaker than the (primary) reflections at the technically adjusted reflective surfaces. For example, these additional reflections can be one or more orders of magnitude weaker than the primary reflection. Coatings designed for the desired optical effect can also be applied to both one and the opposite sides. Thus, for example, the (primary) reflections on both the front and back sides of the substrate can be technically adjusted, i.e., their optical properties can be modified. One side of the substrate can also have multiple coatings; correspondingly, the micromirror elements can each have a large number of reflective surfaces.

[0012] In this context, "multiple micromirrors" can refer to, for example, at least 20, at least 100, or at least 1000 micromirrors. The reflective surfaces are small, as with common micromirrors, for example, <100 mm² or <20 mm². Because the micromirrors are movably mounted in the support structure, each reflective surface can be oriented in two dimensions, achieving angular alignment. Thus, even if the eye's orientation and / or position changes, the light emitted by the display unit, i.e., the light from the display unit itself, can still be redirected to the eye or pupil. Since the deflection unit is at least partially (i.e., partially or completely), particularly utilizing micromirror elements, arranged in the light path from the ambient light entering the user's eye from the user's field of vision, a virtual image corresponding to computer-generated image information can be superimposed on real objects in the user's field of vision environment, because the micromirror elements (as required for AR glasses) are at least partially transparent to ambient light. To present the largest possible virtual image without artifacts, thereby achieving a more immersive experience, the system controls the deflection unit and / or display unit according to the orientation of one or both eyes, for example, using a control unit described further below.

[0013] Preferably, all or at least most (preferably almost all) of the micromirror elements (particularly always and / or primarily) are oriented (at least in the standard operating mode of the eyeglass display system) such that only light from the display unit can be directed into the user's eyes. This angular alignment is achieved in the standard operating mode regardless of whether the micromirror elements are illuminated by the display unit. The advantage is that light sources located elsewhere do not produce visible reflections in the eye, thus preventing distracting light reflections that manifest as ghosting. This is particularly advantageous in outdoor applications, where the sun, as an extremely strong light source, often causes unpleasant stray light reflections. Another advantage is that highly reflective materials, such as translucent coatings, can be chosen for the reflective surfaces of the micromirror elements, because even with high reflectivity, unwanted light reflections in the eye will not be amplified.

[0014] Furthermore, the glasses display system may be equipped with an energy-saving operating mode in which micromirror elements (particularly only these elements) not illuminated by the display unit are set to a predetermined stationary position. In this stationary position, the actuator system, including the actuator elements described below, may be fully or partially deactivated. For example, when no virtual image is displayed, or when the virtual image contains a large or persistent black area, the micromirror elements may be moved to this stationary position. Preferably, the micromirror elements are not moved until they are illuminated by the display unit again. The stationary position of the micromirror elements may be preset to correspond to the stationary position of the corresponding associated eye. Therefore, when the micromirror elements are in the stationary position, light from the display unit is essentially only directed into the user's eye when the eye is in the stationary position. However, the reflection conditions are not met at this time, and light coupled from the rear may produce undesirable reflections. Although undesirable ambient light reflections may cause visual artifacts in certain situations, studies have shown that people generally keep their gaze in the aforementioned stationary position or a neutral gaze direction, thereby minimizing the likelihood of such artifacts. Therefore, it is generally advantageous to select the stationary orientation of the micromirror element based on the stationary position of the eye, thereby ensuring that the conditions for light reflection to the projector's exit aperture are met most of the time, even when the actuator is off.

[0015] As an alternative or supplement, a high-quality operating mode can also be provided, in which the angle alignment of the micromirror elements is continuously adjusted. This means that the micromirror elements are continuously tracked to follow eye movements (e.g., even when no virtual image is displayed, or when the virtual image contains large or persistent black areas). Furthermore, the glasses display system may also include sensor devices (such as camera sensor devices) for detecting and / or evaluating the environment, such as current lighting conditions; and an automatic switching device configured to automatically switch between different operating modes based on one or more predetermined switching criteria. For example, the probability of bright spots (which easily cause interfering reflections) evaluated by the sensor devices can be specified as a switching criterion, such that a power-saving mode is activated when the probability is low, and a high-quality operating mode is activated when the probability is high. The environment can also be recorded and analyzed based on location data; for example, bright spots are more likely to occur when the glasses display system is used outdoors than indoors. By specifying appropriate control schemes, power consumption and immersion can be optimized.

[0016] The display unit may include one or more preferably planar screen elements (“displays”) to generate light, but may also include one or more (laser) projector elements. In particular, the display unit may be a stereoscopic display unit capable of generating virtual stereoscopic images within the field of view. For this purpose, the stereoscopic display unit may include two screen elements or two (laser) projector elements, each corresponding to one of the user's eyes. For example, the screen elements or (laser) projector elements may be arranged separately on the temple units of the eyeglass display system on the user-facing side. In this case, ideally, light from the light-emitting pixel elements of the display unit should only fall on one micromirror element, and should not be visible through one or more adjacent micromirror elements simultaneously. In the latter case, the same pixel information will be perceived in two different spatial orientations, i.e., as two different virtual pixels (pixels of a virtual image), because adjacent micromirror elements are typically tilted relative to each other at a non-zero angle, i.e., their orientations are different.

[0017] In one embodiment, the micromirror element and support structure may be arranged within a sealed housing element of the deflection unit, the housing element being filled with liquid. The housing element may be positioned in front of the user's eyes, similar to the lenses of conventional eyeglasses. Therefore, the liquid, micromirror element, and support structure are arranged within the internal space of the housing element, such that the micromirror element and support structure are surrounded by liquid. Accordingly, the housing element has oil- and / or water-resistant properties and is made or constructed of a material that is (at least substantially) transparent to ambient light and light emitted by the display unit, as is the case with conventional eyeglass lenses. The micromirror element and support structure are also advantageously made of transparent materials, as will be further explained below.

[0018] The liquid bath surrounding the micromirror elements and support structure has a damping effect, suppressing vibrations and thus inhibiting unwanted small, rapid changes in the upward orientation of the reflective surface. This is advantageous because the eye makes rapid movements at speeds up to 1000° per second before returning to stillness. Furthermore, the liquid reduces the refractive index difference at the material interface—the difference in refractive index at the boundary between the liquid and the micromirror or support structure. This reduces both Fresnel reflections and other refractive effects. The reduction in reflections and these effects decreases the visibility of elements or structures immersed in the liquid bath, as is seen with glass components immersed in water. This prevents artifacts within the field of view that disrupt the user's immersive experience and allows the micromirror array (“micromirror array”) to be directly visible to the user, within their field of view. However, it is precisely the micromirror array that enables large-area virtual enhancement of the field of view and allows for higher (angular) resolution of the virtual image; therefore, it is a prerequisite for realizing an immersive head-mounted display system comparable in size to commercially available eyeglasses.

[0019] In another embodiment, the micromirror elements and / or support structures and / or other components (such as the inward-facing side of the housing element) surrounded or adjacent to the liquid are designed to be (at least substantially) transparent, as described above regarding the housing element. Therefore, the micromirror elements and / or support structures and / or other components are made of, or contain, a corresponding transparent material having a first refractive index. In particular, the housing element and / or micromirror elements and / or support structures and / or other components can be made of the same material, which helps to match their optical properties.

[0020] The liquid is also (at least substantially) transparent to ambient light and has a second refractive index that matches the first refractive index, meaning the deviation between the two is as small as possible. Therefore, the selected liquid must ensure that the deviation between the second and first refractive indices does not exceed a specified limit of, for example, 0.005, within a specified wavelength range of, for example, 400 nm to 700 nm and / or a specified temperature range of, for example, 0° to 30°. The liquid can also be optimized for one or more sub-ranges of the corresponding range, for example, exhibiting a second refractive index particularly similar to the first refractive index within a wavelength range of 540 nm ± 30 nm and / or a temperature range of 21° ± 2°. Within this sub-range, a correspondingly small maximum deviation limit can be specified, for example, 0.002. Such a "refractive index-matched liquid" with the desired characteristics is commercially available. Therefore, active temperature control of the micromirror array may be advantageous, i.e., measuring its temperature and setting a target temperature or target temperature range by heating or cooling. Therefore, a temperature control device for the liquid can be provided. The temperature control device may include a sensor unit for measuring the liquid temperature and a temperature control unit for adjusting the liquid temperature to a predetermined temperature value, i.e., performing heating or cooling operations based on the measured value and the predetermined temperature. This can avoid or at least reduce temperature-related deviations.

[0021] Therefore, ambient light undergoes minimal refraction as it passes through the deflection unit, ensuring that any changes in ambient light, specifically, remain within the wavelength and / or angular range of ambient light and / or below the user's perception threshold temperature. Consequently, material transitions and the micromirror elements and / or support structures and / or other components thus surrounded by liquid become virtually invisible to the user. Consequently, micromirror elements can be arranged over a large area in front of the user without interfering with their perception of the surrounding environment and, consequently, the virtual image, significantly improving the immersive experience when using a head-mounted display system.

[0022] In one embodiment, an aperture unit adjustable by a control signal may be arranged in the optical path between the display unit and the tiltable micromirror element. This adjustable aperture unit is configured, according to the control signal, to adjust at least one beam position on the deflection unit and / or at least one beam width associated with a corresponding beam position on the deflection unit for light deflected on the reflective surface of the tiltable micromirror element. Therefore, the adjustable aperture unit allows the position of light illuminating the deflection unit to be determined by the adjustable beam position, thereby determining which micromirror elements are illuminated by the light, and / or the size of the area illuminated by the light on the deflection unit to be determined by the adjustable beam width, thereby enabling the exclusion of certain micromirror elements near the beam position from the illumination range, for example, those micromirror elements that would only be weakly illuminated when the beam width is wider (this will be described in more detail below). This adjustable aperture unit can be considered, or referred to as, an aperture scanner because it allows for local scanning of the display unit or deflection unit using an adjustable beam position, wherein an effective aperture (“emission aperture”) is set, and this aperture can be dynamically adjusted with a dynamically adjustable beam width.

[0023] Its effect is that, by using control signals and an adjustable aperture unit (also known as an adaptive aperture), the exit aperture of the display unit that acts on the micromirror element can actually be dynamically set (i.e., adjusted over time by control signals).

[0024] Specifically, the adjustable aperture unit can be arranged in the optical path from the display unit to the deflection unit, i.e., between the projector optical system and the display unit. As previously mentioned, the display unit may or may not include one or more optical systems. These optical systems of the display unit can be configured, in particular, to map the physical pixels of the display unit so that the eye can perceive the corresponding virtual image points (pixels of the virtual image) with the desired clarity. The optical system of the display unit may include (micro)lenses arranged in parallel (rather than in series) in the beam path, particularly a microlens array having multiple microlens elements arranged in parallel in the beam path. The diameter of such microlens elements may, for example, be less than 1000 µm, preferably less than 500 µm, and / or greater than 50 µm.

[0025] The projector optical system may include one or more lenses (of macroscopic size compared to the microlens elements of the microlens array described above). Preferably, the display unit is not arranged in the focal plane of the projector optical system, but the parallel light beam originating from the microlens elements is imaged onto this focal plane. This is because arranging the display unit in the focal plane of the projector optical system would increase crosstalk between the corresponding physical pixels of the display unit and different adjacent microlens elements. In particular, the focal plane may be located between the adjustable aperture unit and the projector optical system. Therefore, the projector optical system helps to enhance immersion by reducing the requirements of the adjustable aperture unit.

[0026] As an alternative or supplement, the projector optical system can be configured according to the imaging formula. The micromirror element is focused onto another focal plane. Preferably, an adjustable aperture unit is then arranged in this additional focal plane. This allows the beam position and / or beam width to be appropriately adapted to the corresponding size and / or position of the micromirror element, thereby improving image quality and thus enhancing immersion.

[0027] In this context, reuse, as can be achieved by adjustable aperture units, allows the same display area of ​​the display in the display unit to be projected onto different micromirror elements at different times.

[0028] Generally speaking (i.e., without considering aperture elements), the effective exit aperture of the display unit is presented to the eye in a mirror form through each micromirror element. If a very large exit aperture is chosen, any necessary multiplexing becomes more complex, and the weight of the AR glasses increases without providing any additional value. Therefore, when designing the exit aperture (i.e., its diameter), it is desirable to keep the diameter as small as possible. If the exit aperture of the display unit is too small, it is impossible to project virtual images in every direction in the user's line of sight; therefore, the virtually expandable field of view is relatively small. Alternatively, if a large number of micromirror elements are used, gaps will appear in the virtual image because not every (required) virtual pixel will have a beam of light directed to the physical pixel.

[0029] Therefore, the exit aperture of the display unit needs to have a certain minimum size to ensure that light can propagate along the path from the display unit to the micromirrors and from the micromirrors to the eye in all AR viewing angles, thereby providing the largest possible virtual augmented field of view. Thus, the pixel image is projected as a beam of light onto the micromirrors of the deflection unit (i.e., the overall "micromirror array"), the diameter of which is the same as the exit aperture of the display unit. A typical diameter of the exit aperture is, for example, 8 mm. The typical diameter of the micromirrors or their reflective surfaces is 2 mm to 4 mm. Therefore, the beam of light carrying pixel image information will simultaneously illuminate several adjacent micromirrors. Since each micromirror is ideally aligned, such that the pupil-centered line of sight images onto the center of the display unit's exit aperture according to the eye's current orientation, the following situation may occur: light from a single image information pixel may simultaneously fall on two adjacent micromirrors, and thus may be seen by the eye simultaneously. However, due to the different alignment of adjacent micromirrors, the image information of the same pixel may be perceived in two different reflection directions, resulting in one or more virtual ghostings.

[0030] Thanks to the adjustable aperture unit, for each image information pixel, only the cropped beam is projected onto different micromirror elements, so that the light falling on the corresponding (next) adjacent micromirror element is as little as possible, or is limited to light that will not enter the pupil and thus be invisible, or light that is too weak to cause interference.

[0031] Therefore, it is advantageous to design the adjustable aperture unit as follows: for each micromirror element, the provided virtual image viewing direction satisfies the condition that the area covered by light illuminating or directed towards the corresponding micromirror element in that direction is greater than the area covered by other (immediately adjacent) adjacent micromirror elements. For extreme viewing directions that primarily (i.e., at least most) illuminate adjacent micromirror elements and thus only minimally (e.g., merely glide past) the currently viewed micromirror element, their emission aperture should ideally no longer illuminate the display unit's exit aperture. Therefore, for micromirror elements viewed at a given time (e.g., at a specific multiplexing moment in time-division multiplexing), a smaller display unit exit aperture can be selected to improve image quality. This is achieved through the adjustable aperture unit. Figure 7f An example of this situation is shown.

[0032] Its advantage lies in minimizing diffraction effects during the imaging process and achieving the highest virtual image sharpness. This is because the micromirror element, which redirects only a small portion of the total beam initially emitted by the display unit to the eye, acts as the aperture. Therefore, if it is only partially reflected, the beam can be confined. According to optical principles, diffraction increases as the aperture decreases. Therefore, it is advantageous to position the beam on the micromirror element using an adjustable aperture unit, so that it is not or barely truncated by the micromirror element. Figure 7c The diffraction effect was used as an example to demonstrate this.

[0033] In another embodiment, the adjustable aperture unit is configured to adjust the beam position by adjusting at least one position of at least one transparent partial aperture region, wherein the transparent partial aperture region is located within the total aperture region, and the total aperture region can be switched between transparent and opaque states by a control signal, i.e., the partial aperture region becomes transparent by the control signal. The remaining regions in the total aperture region that are complementary to at least one partial region are opaque, i.e., switched to an opaque state by the control signal. Therefore, one or more partial aperture regions can be switched to a transparent state such that only these partial aperture regions allow light from one or more pixel image data points allocated to the respective partial aperture regions to pass through, while other pixel image data points cannot illuminate the deflection unit. As described below, the position of the transparent partial aperture region can vary over time, for example, to implement a time-division multiplexing method. The advantage of doing so is to prevent or at least reduce crosstalk of pixel image information, which, for example, can cause the aforementioned ghosting phenomenon. Therefore, even with a large field of view, image quality is improved, and the immersive experience of the system is enhanced. As further explained below, the terms "transparent partial aperture region" and "opaque remaining region" can also be understood as follows: within the partial aperture region and the remaining region, light is altered in a non-absorbent manner, such that light incident on the transparent partial aperture region is ultimately visible to the user, while light incident on the opaque remaining region is ultimately invisible to the user. This can be achieved as an alternative to absorption, for example, by altering the polarization characteristics of the corresponding light, as described below.

[0034] In this context, it is possible to simultaneously switch several different, particularly non-adjacent, partial aperture regions to a transparent state. For example, each of the simultaneously switched partial aperture regions may correspond to one or more adjacent switchable pixels of one or more pixelated liquid crystal elements. Preferably, each simultaneously transparent partial aperture region is assigned to a different physical pixel of the display unit, i.e., it is transparent to light from different physical pixels of the display unit. This improves the brightness of the virtual image. In particular, each simultaneously transparent partial aperture region may belong to different partial aperture region groups, wherein each partial aperture region in these different partial aperture region groups is assigned to a different physical pixel of the display unit. This enables time-division multiplexing: the physical pixels of the display unit assigned to the corresponding group provide computer-generated image information as light to the virtual image pixels of the semi-transparent aperture regions assigned to the corresponding semi-transparent aperture region groups at different times.

[0035] In another embodiment, the adjustable aperture unit includes or is an electromechanical aperture element. This electromechanical aperture element has an aperture that is displaced in a plane traversing the transmitted light path when the beam position is adjusted, for example by a microelectromechanical mirror (“MEMS mirror”). Alternatively or supplementary, in addition to the embodiments employing pixelated (particularly ferroelectric) liquid crystal elements described below, the aperture unit may include one or more switchable polarization diffraction gratings. When the beam position is adjusted, the transmitted light can be deflected in several different directions depending on the applied voltage. To achieve lateral displacement, a reverse diffraction grating is connected downstream of each diffraction grating, such that the first diffraction grating causes an angular change, which is compensated for by a second diffraction grating. By offsetting these two diffraction gratings along the optical axis, the original aperture is laterally displaced in a plane perpendicular to the optical axis. The corresponding technical implementation was published in: Guo, Qi, et al. "Fast switching beamsteering based on ferroelectric liquid crystal phase shutter and polarizationgrating." Liquid Crystals 46.9, (2019): 1383-1388.

[0036] In another embodiment, the adjustable aperture unit is configured to adjust, according to a control signal, the beam width associated with each beam position, in addition to adjusting at least one beam position, for light deflected at the reflective surface of the tiltable micromirror element. Specifically, the beam width can be adjusted by adjusting the area and / or diameter of at least one transparent partial aperture region associated with a corresponding beam position within the total aperture region, which can be switched to a transparent state (particularly a transparent or opaque state) via a control signal. In particular, the beam width can also be adjusted differently for different beam positions. This optimizes image quality, especially for micromirror elements with reflective surfaces of different sizes at different beam positions. Because of the dependence on the control signal, the beam width can be adjusted (and / or preset) to vary over time and / or adapt to beam positions that change over time. This improves the performance of the multiplexing method and enhances image quality.

[0037] In one embodiment, the beam width of the emitted light in the optical path prior to the adjustable aperture unit is greater than the diameter of the reflecting surface of the corresponding illuminated micromirror element. This applies to parallel light; otherwise, the beam width at the reflecting surface must be compared with and without the aperture unit. This allows for particularly good optimization of the effective beam width, as the beam position can be determined very easily to achieve favorable illumination of one or more reflecting surfaces, i.e., large-area illumination.

[0038] In one embodiment, the adjustable aperture unit is designed to adjust the beam width to be smaller than the diameter of the reflective surface of the corresponding illuminated micromirror element, particularly (in the case of micromirror elements with reflective surfaces of different sizes) smaller than the diameter of the reflective surface of one of the illuminated micromirror elements. This allows light to be guided from the deflection unit into the eye with minimal artifacts (such as ghosting), thereby improving image quality and enhancing the immersive experience of the system.

[0039] In another embodiment, the adjustable aperture unit is configured to adjust the beam position and beam width of light such that at least (particularly always) most of the light passing through the adjustable aperture unit illuminates the reflective surface of exactly one micromirror element as a single beam. Alternatively, the transmitted light may illuminate multiple micromirror elements as multiple (particularly non-intersecting) transmitted beams, each transmitting beam illuminating at least most of its corresponding beam onto the corresponding micromirror element, the beam position and beam width of each transmitted beam being determined by the adjustable aperture unit. This can be achieved, for example, by simultaneously making multiple partial aperture regions within the total aperture area transparent. "Most" can be understood as at least 50%, preferably at least 65%, and most preferably at least 80%. This enables the display of particularly bright and clear virtual images. In both cases, the display unit can be partially shut off, thereby preventing (generated and emitted) light from adversely falling onto the deflection unit and achieving this effect through more targeted light emission. On the one hand, this is more energy-efficient; on the other hand, based on the relationship between the user's line of sight and the geometry of the AR glasses, better image quality can be achieved by adjusting the beam solely through the aperture unit, or by combining the beam adjustment of the aperture unit with the beam adjustment of the display unit when a specific area is off. By selectively deactivating multiple spatially separated active physical pixels, and combining this with a given adjustment or setting of the aperture unit, spatially separated virtual pixels can also be generated at a given time. Light from different physical pixels passes through the transparent aperture area, then falls at a given time, generating virtual pixels at spatially separated positions. Subsequently, region-by-region deactivation reduces artifacts and improves imaging results.

[0040] In another embodiment, a frame rate is specified for the computer-generated image information; and the aperture unit is configured to adjust (specifically change) the beam width and / or beam position multiple times within a specified time interval for the image, according to the frame rate. Thus, the beam width and / or beam position are adjusted / changed at a frequency higher than the frame rate (“subframe rate”), calculated by multiplying the frame rate by the number of beam positions (corresponding to the scan positions of the exit aperture). Subsequently, the image information of a pixel may be displayed only in one or a few subframes within a single frame. Therefore, in order to control the display unit, in addition to the pixel image information, the scan position, i.e., the angular deflection of the associated micromirror element when light is transmitted through the aperture unit at a corresponding time, must also be known. This angular deflection then determines the display time of the corresponding pixel image information, or vice versa, as is well known in scanning methods.

[0041] Specifically, if the exit aperture of the display unit is larger than the reflective surface of the micromirror element, then for each "frame," the exit aperture will be in more than one scanning position. At these scanning positions, the way light is directed towards the micromirror ensures that the corresponding pixel image information is only visible in the spatial direction reflected by the micromirror. Therefore, using the above-described (subframe) time-division multiplexing, the same physical pixel of the display unit can technically realize different virtual pixels of a virtual image. This requires a display unit that can synchronously display multiple (at least two) pixel image information using pixels within a subframe of a single frame, along with changes in the angular orientation of the micromirror element (using an exit aperture scanner).

[0042] This produces a unique technical effect: more virtual pixels are achieved than the number of physical pixels available. For example, if light reflects from the side, the display unit might need to be able to scan a 50° field of view. If this field of view is doubled using a mirror, only about 50° / 100° = ½ physical pixels are physically needed, with all the remaining virtual pixels achieved through time-division multiplexing of adjacent physical pixels. The advantage is that smaller displays can be used, allowing for further miniaturization of the entire system.

[0043] The aperture unit is configured to adjust the beam position to at least 3, particularly at least 7, preferably at least 10, most preferably at least 200, and especially preferably 400 different beam positions within a time interval specified by the refresh rate for the image. Corresponding transparent aperture regions can be assigned to the corresponding different beam positions. The number of transparent aperture regions, determined by the number of beam positions, can, for example, be simultaneously switched to a transparent state. This allows light to be guided onto the micromirror element with exceptional flexibility, thereby achieving extremely high image quality.

[0044] The aperture unit is configured to adjust the beam width and / or beam position at a frequency of at least 100 Hz, preferably at least 1000 Hz, and most preferably at least 20 kHz. A frequency of at least 100 kHz is also feasible. µLEDs are particularly suitable here because they are capable of operating at extremely high on / off switching frequencies (currently up to 300 kHz) and achieving high brightness (light intensity) in the process.

[0045] Therefore, a control unit can be provided, configured to control the adjustable aperture unit via a control signal and, via another control signal, control the display unit according to time-division multiplexing, in which at least two virtual pixels of the virtual image are assigned to a physical pixel of the display unit. Thus, time-division multiplexing ensures that light from the physical pixel illuminates the reflective surfaces of different micromirror elements at different times.

[0046] For example, a GPU can be used as a control unit to calculate the image to be displayed as a virtual image. Each pixel of this image represents pixel image information to be displayed in a certain spatial direction within the user's field of vision. However, in this method, as the eye's orientation changes, the mirrors continuously move, guiding light into the viewer's pupil. Although the radiation direction of the display unit remains constant, since what is observed is light deflected by the deflection unit, a new mapping relationship between physical pixels and virtual pixels in the specified spatial direction must be calculated each time the micromirror elements move in order to display image information in that specified spatial direction. For this purpose, the angular orientation or direction of each micromirror element must be known. To achieve this, each micromirror element can be equipped with an independent angle sensor to measure its respective angular orientation, or the control precision of the micromirror elements can ensure that their controlled positions are sufficiently accurate. For example, a lookup table can store the corresponding pixel-to-spatial-direction mapping rule for each mirror position. Therefore, this mapping rule can define the mapping from each virtual pixel of the virtual image to the corresponding physical pixel of the display unit, and this mapping changes with the eye's orientation. Therefore, the content of a virtual pixel can be specified by different physical pixels and / or different micromirror elements or their angular orientations for different eye orientations (and thus at different times) according to this mapping rule.

[0047] During the process of switching from one micromirror element to another, if the light beam is directed at both micromirror elements at the same time, the intensity of the light beam entering the eye may be reduced because not the entire area of ​​the light beam can reach the eye. For example, in extreme cases, half of the light beam may be directed at each micromirror element separately. Figure 7c This has been explained. Compared to the light path where the beam is directed towards the center of the micromirror element, the intensity perceived by the viewer is reduced in this case. As will be further explained below, in this situation, it may be more advantageous to increase the physical brightness of the corresponding physical pixels, thereby allowing the user to perceive a more uniform image brightness.

[0048] In one embodiment, the aperture unit includes or is one or more pixelated liquid crystal elements, particularly pixelated liquid crystal elements employing bistable liquid crystals, which can be divided into independently switchable volumes. Pixels of such pixelated liquid crystal elements can be individually switched to a transparent or opaque state, and as the smallest switchable unit, can be individually or in combination with adjacent pixels to form a portion of the aperture unit that can be switched to a transparent or opaque state. One option is to arrange the pixelated liquid crystal elements (and thus also include the aperture unit, at least partially, i.e., partially or entirely) in the beam path near the deflection unit, for example, by integrating them into the eyepiece lens. Another option is to arrange the pixelated liquid crystal elements (and thus also include the aperture unit, at least partially, i.e., partially or entirely) in the optical path near the display unit, for example, by integrating them into or placing them on the optical system of the display unit. For example, arranging them within the beam path near a particular unit can be understood as arranging them within 25%, particularly 10%, of the beam path closest to the corresponding unit. The advantage of pixelated liquid crystal elements lies in their ability to adjust the beam position and / or beam width extremely quickly and precisely, thereby easily "turning on" or "activating" a single micromirror element—that is, displaying a virtual image by illuminating that single micromirror element. This enables, for example, time-division multiplexing with good image quality. The liquid crystal elements also do not need to be arranged on a single plane. Degrees of freedom can be created based on the distance between the nearest adjacent micromirror elements, allowing for more flexible positioning of the liquid crystal elements on different planes. By switching the aperture unit (in this case, the liquid crystal element), it is only necessary to prevent the physical pixels of the display unit from being perceived simultaneously via two micromirror elements. To achieve this, it may also be sufficient if the intensity of one (or more) additional beam paths from the physical pixel to the eye is attenuated to a level that is not perceived as interference (i.e., not considered interference compared to the main perceiving beam path originating from that physical pixel or other physical pixels).

[0049] However, if simple pixelated liquid crystal elements are used near the deflection unit without any other components, the AR glasses become opaque to ambient light because most micromirror elements are in an "off" state at any given moment during the time-division multiplexing cycle. This results in very low transmittance even at high-speed scanning.

[0050] To circumvent this problem, in one embodiment, the pixelated liquid crystal element is (especially only) or includes a switchable waveguide, and the aperture unit includes, in addition to the liquid crystal element, a first static polarization element, and particularly a second static polarization element. If two polarization elements are included, they are each transparent to different polarization states. For example, the first polarization element may be transparent to s-polarized light, and the second polarization element may be transparent to p-polarized light, and vice versa; or, this can also be analogously applied to two other states, such as circular polarization. The first polarization element is arranged in the optical path between the display element and the pixelated liquid crystal element, preferably in the beam path at and / or near or inside the display unit. The second polarization element is arranged in the optical path between the pixelated liquid crystal element and the micromirror element, preferably in the beam path at and / or near or inside the deflection unit.

[0051] If only a first polarizing element exists, it is arranged in the optical path between the display element and the pixelated liquid crystal element, preferably at and / or near or inside the deflection unit in the beam path. The first polarizing element may be transparent to either s-polarized or p-polarized light. In this embodiment, the first polarizing element is arranged such that light deflected into the eye by the deflection unit also passes through it. In this embodiment, the light perceived by the user passes through the first polarizing element twice, i.e., through the first polarizing element but not through the second polarizing element. The switchable waveplate is a switchable λ / 4 waveplate that converts linearly polarized light via the first polarizing element into circularly polarized light. Upon reflection at or within the deflection unit, the circular polarization state is reversed, i.e., right-handed light becomes left-handed light, and vice versa. When passing through the switchable waveplate and the first polarizing element again, the aperture unit, i.e., the switchable waveplate, can be adjusted to select which light is transmitted through the aperture unit and which is not. Since ambient light can be considered very close to unpolarized light, the view of the natural environment remains unobstructed in this case.

[0052] The adjustable aperture unit is designed to adjust the beam position of light incident on the micromirror element by adjusting the polarization conversion characteristics of the total aperture region, so as to convert the polarization state in the transparent aperture region while keeping the polarization state of the remaining region of the total aperture region unchanged except for the partial aperture region, and vice versa.

[0053] For example, in an embodiment with two polarization elements, unpolarized light emitted by the display unit can first be converted to a first polarization state, such as an s-polarization state, by the first polarization element. In at least one transparent portion of the aperture unit, the polarization state is converted, for example, to a p-polarization state, while remaining unchanged in the remaining region. Before illuminating the micromirror elements, light of both polarization states is directed to the second polarization element, which is transparent only to light of the second polarization state. By selecting the transparent region of the aperture and based on an understanding of the geometry between the display unit, the aperture unit, the deflection unit, and the eye position, it is possible to determine which micromirror elements are illuminated and which are not. Subsequently, according to the above definition, the transparent portion of the aperture region is defined as the aperture region through which light passes (transmits) and ultimately enters the user's eye, and this light is visible in the transparent portion of the aperture region due to the adjustable characteristics of the aperture unit. Next, according to the above definition, the opaque remaining aperture region is defined as the aperture region through which light passes (transmits) but ultimately does not enter the user's eye, and this light is not visible in the opaque remaining aperture region due to the adjustable characteristics of the aperture unit.

[0054] The second polarized light reflected by the illuminated micromirror element is then superimposed on the ambient light (which is typically unpolarized); after passing through the second polarizing element and the pixelated liquid crystal element again, the light is projected into the user's eye. Because ambient light also has polarization properties, the AR glasses will darken like sunglasses, since only one polarization state, half of the light, can pass through the second polarizing element.

[0055] As an alternative to arranging the pixelated liquid crystal elements near the deflection unit, in one embodiment, the pixelated liquid crystal elements are arranged near the display unit. Therefore, the pixelated liquid crystal elements are arranged in the optical path between the display unit and the deflection unit, but not in the optical path between the micromirror element and the eye. This avoids a darkening effect similar to that produced by sunglasses in the above embodiment.

[0056] In this configuration, by sequentially switching different portions of the aperture region within the total aperture area illuminated by the display unit to a transparent state and switching the corresponding remaining regions to an opaque state, the adjustable aperture unit can be used to scan the exit aperture of the display unit at discrete positions. The transparent aperture regions can be circular, square, or hexagonal, etc. The transparent aperture regions overlap during consecutive time steps. Therefore, these transparent aperture regions form one or more sub-apertures at each time step.

[0057] As an alternative to the overlapping sub-apertures described above, the aperture regions that switch to a transparent state during consecutive time steps can also be selected as non-intersecting. Therefore, the exit aperture of the display unit is divided into adjacent regions or sub-apertures for scanning by the micromirror elements. The advantage of this is that the display unit only needs to render a small number of subframes, thus reducing the requirements on display unit speed and required brightness intensity. This leverages the fact that light simultaneously illuminating a micromirror element and its nearest neighbor typically does not enter the pupil in both cases. Due to the different angular positions of adjacent micromirror elements, light from adjacent micromirrors usually points towards the region next to the pupil. This reduction in the minimum requirements of the display unit also has a positive impact on image quality.

[0058] The electrical structure required to switch liquid crystal elements can cause diffraction effects during transmission, thus degrading image quality. However, the diffraction effect can be controlled by selecting the size of the structure, preventing diffraction orders from reaching the eye and thus becoming invisible to the user. A significant advantage of this is that the micromirror elements are extremely small, so even slight angular deviations in light passing through the aperture unit will prevent them from reaching the pupil.

[0059] In another embodiment, the eyeglass display system includes an additional focusing unit, particularly comprising or consisting of an electrically adjustable liquid-controlled lens, disposed in or on the display unit. This focusing unit is designed to move the focal plane of the light emitted by the display unit according to an additional control signal. Therefore, this focusing unit may be referred to as an adaptive focusing unit. For example, the additional focusing unit may be designed to resolve convergence-accommodation conflict problems and / or compensate for the user's visual impairment.

[0060] By selecting an adaptive aperture smaller than the human pupil (i.e., using an adjustable aperture unit where the transparent portion of the aperture is smaller than the pupil), the depth of field of the projected image can be increased. Therefore, from a human perspective, the virtual image is not only clear at a specific distance but also remains clear within a certain range. Similarly, as long as the target distance is within the depth of field, clear imaging can be achieved at different distances without the need for an additional focusing unit, effectively resolving the convergence-accommodation conflict problem. The beneficial effect of a small effective aperture on depth of field can also be combined with a focusing unit to achieve clear imaging of areas exceeding the depth of field at different distances in front of the viewer.

[0061] Because the adaptive aperture unit and the human eye's pupil limit the effective diameter of the virtual pixel's optical path, the requirements for the projector's optical system are advantageously reduced. This allows the projector's optical system to use a larger aperture ratio, i.e., a large aperture, since only a small portion of the optical system needs to form a sharp image. This simplifies the design and manufacturing of the projector's optical system. A larger aperture ratio also allows for a shorter focal length, thus enabling the use of smaller displays, which is beneficial for miniaturization designs.

[0062] An additional focusing unit allows the focus of the virtual image to be adjusted to the current viewing position. This can be achieved using information about eye orientation (i.e., "eye tracking"), as further described below. Preferably, the focus of the entire virtual image is uniformly changed, for example, by using an electrically adjustable liquid-controlled lens ("liquid lens"). However, other optical methods can also be employed, such as stacking multiple transparent displays. Using a flat reflective surface, arbitrary focal lengths of the display unit can be achieved without introducing aberrations; in contrast, other known beam-splitting techniques, such as so-called "waveguides," must be designed for a fixed, predetermined focal length.

[0063] By utilizing additional focusing units, particularly liquid lenses, users' visual impairments can be dynamically compensated for regardless of whether the convergence-accommodation conflict is resolved (i.e., personalized compensation for different users). In this case, additional lens elements must be placed in the optical path of ambient light entering the eye from the field of vision, i.e., between the environment and the deflection unit. For example, in this scenario, users can layer conventional glasses for vision correction on top of AR glasses, or use appropriate add-ons. Further optimization of vision correction can be achieved by placing additional lens elements between the display unit and the deflection unit.

[0064] Flat reflective surfaces are particularly advantageous if an additional focusing unit is present, as this ensures the focusing unit has the greatest possible flexibility and application range. In contrast, concave reflective surfaces achieve extremely high light efficiency. Using a concave reflective surface, it can be ensured that light emitted from only a single physical pixel in the display unit is projected onto the corresponding micromirror and thus precisely redirected to the position in the user's eye where the virtual image is expected to appear. Therefore, multiplexing is not required in this case. Concave reflective surfaces can also be chosen for direct focusing onto the display unit. This eliminates the need for additional optical elements; however, all micromirror elements simultaneously image the display unit. Therefore, a multiplexing method must be employed to explicitly map pixel information (light from the physical pixels of the display unit) to the viewing direction. Regardless of whether their shape is flat or concave, reflective surfaces can have different sizes and / or at least partially overlap. Hexagonal shapes are advantageous due to their good surface coverage.

[0065] In one embodiment, the glasses display system includes an eye-tracking device for determining the user's eye orientation and a control unit for controlling a deflection unit based on the determined eye orientation. This allows light to be precisely directed to the pupil, thereby improving light efficiency and avoiding adverse effects such as "eye glow," which is the redirected light reflection perceived by a third party in the user's eyes. Thanks to improved energy efficiency, the weight of the battery and the required size of the display unit can be reduced, thus enhancing immersion.

[0066] In this context, the control unit can be configured to control the display unit according to a mapping rule stored within it. This mapping rule specifies the mapping from individual virtual pixels of the virtual image to the corresponding physical pixels of the display unit, and this mapping varies with the eye's orientation. Therefore, the content of the virtual pixels depends on the different physical pixels corresponding to different eye orientations (and thus at different times). This is because the mapping between the physical pixels of the display unit and the virtual pixels of the virtual image always changes whenever the micromirror element moves, and this change occurs differently for each pixel combination. This non-linear change is compensated for by the mapping rule, thereby maintaining the virtual pixels within the virtual image in their desired positions. This improves image quality and enables particularly large virtual images.

[0067] In another embodiment, the display unit is configured to adjust the intensity of light emitted toward each beam position regulated by the aperture unit. Specifically, this is achieved such that the luminous flux arriving at different beam positions sequentially or simultaneously is matched. This matching should be understood in the context of the virtual image to be displayed. Because the luminous flux is matched for different beam positions, the perceived brightness of the virtual image is expected to be uniform; however, uneven brightness or areas of light or dark may still occur in the virtual image. The adjusted light intensity aims to achieve uniform image brightness by compensating for light loss caused by the aperture unit in each viewing direction and achieving a two-dimensional light intensity distribution specified for the virtual image.

[0068] The features and combinations thereof described herein, including those in the overview section and those disclosed in the accompanying drawings or only in the drawings, can be used alone or in combination as described, in combination with other features, or even without including some of the disclosed features, all without departing from the scope of the invention. Therefore, embodiments constituted by combining the various features disclosed in the drawings, even if not explicitly shown and described in the drawings, are also within the scope of the invention. Therefore, embodiments and combinations of features that do not include all the features of the original independent claims should also be considered disclosed. Furthermore, embodiments and combinations of features that deviate from or exceed the scope of the dependent claims should also be considered disclosed.

[0069] In the context of this disclosure, "lateral / along the direction of" can be understood as "at least substantially perpendicular / parallel," meaning "perpendicular / parallel" or "substantially perpendicular / parallel," indicating a perpendicular / parallel relationship except for a specified deviation. For example, the specified deviation may be at most 15°, preferably at most 5°, and most preferably at most 3°. Accordingly, in the context of this disclosure, "opposite orientation" can be understood as "at least substantially opposite orientation," meaning "at least substantially antiparallel." The qualifier "substantially" may also refer to a specified maximum permissible deviation expressed as a percentage, such as at most 15%, preferably at most 5%, and most preferably at most 3%. Detailed Implementation

[0070] The exemplary embodiments are described in more detail below with reference to the schematic diagrams. Wherein:

[0071] Figure 1 shows a plan view of an exemplary embodiment of the glasses display system;

[0072] Figure 2 Another top view of the embodiment shown in FIG1 is shown, illustrating the effective pixel multiplication;

[0073] Figure 3 A further top view of the embodiment shown in FIG1 is illustrated, showing effective pixel merging;

[0074] Figure 4 Another top view of the embodiment shown in FIG1 is shown, in which a combined transparent portion aperture region is employed;

[0075] Figure 5 A schematic diagram illustrating the effect of finite aperture size is shown;

[0076] Figure 6 shows a top view of an exemplary embodiment of the aperture unit;

[0077] Figure 7 shows an exemplary illustration of different beam positions on the micromirror array;

[0078] Figure 8 illustrates an exemplary embodiment of the aperture unit arranged on the deflection unit;

[0079] Figure 9 A plan view of an exemplary embodiment of a spectacle display system with an additional focusing unit and refractive power correction is shown.

[0080] Figure 10 Another embodiment of a glasses display system under glare conditions is shown;

[0081] Figure 11 shows a front view and an interior view of another exemplary embodiment of the glasses display system;

[0082] Figure 12A further schematic diagram of an exemplary embodiment of the glasses display system is shown; and

[0083] Figure 13 shows a series of schematic diagrams illustrating various forms of reuse.

[0084] In the accompanying drawings, identical or functionally equivalent features are indicated by the same reference numerals.

[0085] Figure 1 shows a plan view of an exemplary embodiment of the glasses display system, illustrating half of it, i.e., the portion for one eye. For both eyes, the system can be symmetrically expanded.

[0086] Figure 1a Half of the eyeglass display system 1 is shown, for example, the left half viewed from above or the right half viewed from below. Light 163'', 161'', 162'' is emitted by the display unit 14 (arranged laterally here) and, in this example, imaged via the optical system 13, such that these lights 163'', 161'', 162'' are (partially) reflected by micromirror elements such as 12, 12', 12'' of the deflection unit 17, thereby illuminating or directing them toward the pupil 11 of the eye 10. The optical system 13 may include one or more lenses and / or mirrors and / or other optical components. Here, the eye is directed toward a central line of sight B (parallel to the y-direction). If the micromirror elements 12, 12', 12'' (e.g., typically about 2 mm in size) are designed to be at least substantially transparent to ambient light, the natural environment 100 can be viewed through light rays such as 161', 162', 163', and the virtual image formed by the light rays 161'', 162'', 163'' can be superimposed with the ambient light rays 161', 162', 163''. The optical system 13 can be designed to allow the virtual image to be viewed in a focused state at a finite distance or at infinity. The micromirror elements 12, 12', 12'' are mounted to be tiltable, thereby allowing their angular orientation to be adjusted in two dimensions.

[0087] In this example, the micromirror elements 12, 12', 12'' and the support structures for these micromirror elements 12, 12', 12'' (not shown in the figure for clarity) are optionally arranged within a sealed housing element 17a filled with liquid 23. In this case, the selected liquid 23 makes the refractive index between the micromirror element material and the liquid as consistent as possible. It is well known that when glass components are immersed in liquids with nearly identical refractive indices, they become invisible. Two effects occur in this process. First, Fresnel reflection, which would normally occur, disappears when light travels from one medium to another with a different refractive index. Second, light does not refract at the material interface. However, even with a very small difference in refractive index, partial and total reflection can still occur when light strikes the interface at a very small angle.

[0088] In this embodiment, by combining the exemplary determination of the orientation of the eye 10 and the position of the pupil 11 using the eye-tracking device 15, light 163'', 161'', and 162'' from the optical system 13 can be guided very precisely into the pupil 11 of the eye 10. When eye movements occur, for example... Figure 1b As shown in the lateral eye movement, the position of the pupil 11 changes, and the micromirror elements 12, 12', and 12'' are aligned accordingly, allowing light 163'', 161'', and 162'' from the optical system 13 to be precisely directed back towards the pupil 11. In addition to the support structures for the micromirror elements 12, 12', and 12'', these micromirror elements 12, 12', and 12'' are also equipped with one or more actuator elements (not shown in the figure for clarity) for adjusting the angular alignment and thereby setting the corresponding reflection angle; in this case, an independent angle sensor (also not shown in the figure) is additionally provided for measuring the current angular alignment.

[0089] This enables the implementation of control loops for tracking micromirror elements 12, 12', 12'', thereby directing light 163'', 161'', 162'' from optical system 13 toward the pupil 11 of eye 10. For this purpose, eye-tracking device 15 measures the position of pupil 11, and control unit calculates the target angular orientation of micromirror elements 12, 12', 12'', and then compares it with the actual positions of micromirror elements 12, 12', 12''. Actuator elements then compensate for the difference between the actual and target values, striving for a sufficiently high speed so that eye 10 can stably perceive the virtual image even during movement. A speed of 1000° / s is considered the maximum speed of eye movement, from which the minimum processing speed can be derived.

[0090] When the angular orientation of the micromirror elements 12, 12', and 12'' changes, the direction of the line of sight also changes with the new orientation of the eye 10, thus deviating from the central line of sight B. (Comparison) Figure 1a and Figure 1b It can be observed that, Figure 1a Light 161'' is reflected as light 161, while... Figure 1b The light is reflected as light 161b, where light 161b and light 161 have different directions. As a result, the mapping relationship between each virtual pixel of the virtual image and the corresponding physical pixel of the display unit 14 changes, and the image information emitted by the display unit 14 along direction 161'' must adapt to the changing angular orientation.

[0091] Therefore, when eye movement occurs, not only should the orientation of the micromirror elements 12, 12', 12'' be adjusted, but also the pixel light image information generated on the display unit 14 should be adjusted. However, since the geometric layout from the projector to the micromirrors is known, the laws of optics can be used to calculate which new image information must be displayed so that the viewer can perceive that the virtual image has not shifted from the predetermined pupil position (i.e., the designated "eyebox" area), and the corresponding mapping rules can be stored in the control unit of the display unit 14.

[0092] Preferably, the micromirror elements 12, 12', 12'' are driven such that the central line of sight, i.e., the line of sight emanating from the center of the pupil and directed toward the center of the assigned micromirror element, is redirected to the center of the optical system 13, for example along... Figure 1b The light 163b is contained within the micromirror elements 12, 12', 12''. As previously mentioned, changes in the tilt angles of the micromirror elements 12, 12', 12'' alter the viewing angle of the pixel image information presented by the display unit 14; therefore, rather than continuously adjusting the micromirror elements 12, 12', 12'', it is preferable to adjust them in steps according to a threshold that defines the permissible degree of off-center when the light 163b is directed toward the pupil 11 of the eye 10. It is advantageous that the eye makes minute movements, thus eliminating the need for compensation for these movements. It is also advantageous that the micromirror elements 12, 12', 12'' are embedded in a liquid 23, which has a damping effect and suppresses vibrations (i.e., small, rapid angular movements).

[0093] Furthermore, an aperture unit 70, adjustable via a control signal, is arranged in the optical path between the tiltable micromirror elements 12, 12', 12'' of the display unit 14 and the deflection unit 17. In this invention, the aperture unit 70 is arranged in the optical path or beam path near the display unit. This dynamically adjustable aperture unit 70 is configured to adjust the position of at least one beam of light deflected by the reflective surface 25 of the tiltable micromirror elements 12, 12', 12'' according to the control signal, such as... Figure 2 As detailed in the examples.

[0094] Figure 2Another top view of the embodiment shown in FIG1 is illustrated, showing the effective pixel multiplication. The optical system 13 used herein defines the exit aperture 41 of the display unit 14. This aperture 41 is larger than the micromirror elements 12, 12', 12'' or their reflective surfaces 25. Therefore, the light emitted by the physical pixels 14a of the display unit 14 forms a beam with peripheral rays 60, which simultaneously falls on several adjacent micromirror elements 12, 12', 12'' and other applicable elements. This beam reproduces the pixel image information from the display 14. Because adjacent micromirror elements 12, 12', 12'' have different tilt angles, the image information of the same physical pixel 14a is seen by the human eye 10 through multiple beams 61, 62, and 63. However, this phenomenon occurs at different positions 100a, 100b, 100c in the field of view, resulting in the image information of pixel 14a being repeatedly presented within different solid angle ranges. This corresponds to an artifact known as "ghosting."

[0095] The adjustable aperture unit 70 prevents the generation of such artifacts. This aperture unit, positioned downstream of the beam path, adjusts or reduces the position and diameter of the beam with rim rays 60, ensuring that only one of the micromirror elements 12, 12', and 12'' is illuminated. This is achieved by switching a portion of the aperture region 70b (Figure 6) to a transparent state within the total aperture region 70a (Figure 6), which can switch between transparent and / or opaque states. The exit aperture 41 and diameter 40 (…) Figure 3 The relationship between the pupil size and the pupil size is explained below. Figure 5 Further explanation.

[0096] Alternatively, time-division multiplexing can be implemented using the adjustable aperture unit 70, as follows: at different time steps, different portions of the total aperture region become transparent, while the corresponding remaining region (which may include portions of the aperture region that switch to transparency at other time steps) becomes opaque. An exemplary design of the aperture unit 70 or the aperture region of the aperture unit 70 is as follows... Figures 6a-6c As shown.

[0097] In both cases, a unique, particularly one-to-one, mapping relationship was established between pixel image information and micromirrors.

[0098] Figure 3 Another top view of the embodiment shown in Figure 1 is illustrated, showing effective pixel merging. As Figure 2 An alternative or supplement to the scenario shown (i.e., using a single physical pixel to generate different virtual pixels) is to use different physical pixels to form virtual pixels, wherein these different physical pixels and different transparent aperture regions can operate simultaneously or at different times during time-division multiplexing. This will be described below.

[0099] Aperture unit 70 is currently adapted or configured such that two partial aperture regions 70b and 70bb at the edge of the total aperture region 70a are switched to transparent, while the remaining aperture region in the center is opaque. Two different physical pixels (not shown in the figure) of display unit 14 are active, such that first light 161'' (from the first pixel) passes through aperture unit 70 along a first direction and is directed toward deflection unit 17, and second light 162'' (from the second pixel) passes through aperture unit 70 along a second direction and is directed toward deflection unit 17. Since the two pixels are located at different positions, the two directions are different.

[0100] To better illustrate the function of aperture unit 70, in the illustrated configuration, in addition to transmitted light or beams 161'', 162'', all-light or full-beam 161*, 162* are also shown. All-light or full-beam 161*, 162* correspond to light generated by the first and second physical pixels, respectively, which is transmitted through aperture unit 70 when the total aperture region 70a is switched to full transparency. These all-light 161*, 162* have beam widths W corresponding to the aperture of aperture unit 70. Since this aperture and the resulting beam width W are significantly larger than micromirror elements 12, 12', the all-light 161*, 162* are directed toward multiple micromirror elements (not shown) located on plane E.

[0101] By adjusting the position and / or size of the transparent aperture regions 70b and 70bb, the beam position and / or beam width w1 and w2 can be specified by these transparent aperture regions 70b and 70bb. This also determines which micromirror elements 12 and 12' will be illuminated by the corresponding light 161'' and 162''. Combining the angular orientation of each of these micromirror elements 12 and 12' illuminated by the light 161'' and 162'', the viewing direction of the corresponding virtual pixel is determined.

[0102] In the example shown, the viewing direction of the virtual pixel located at position 100a is precisely midway between the two micromirror elements 12 and 12'. The tilt of these two micromirror elements 12 and 12' causes the light rays or beams 161 and 162 deflected or reflected by them to be parallel to each other. Since the two micromirror elements 12 and 12' are (closely adjacent) elements, the light rays 161 and 162 merge, meaning that the distance between them is less than the resolution limit of the human eye. In the example shown, the resulting combined beams 161 and 162 therefore have a beam width w1 + w2, which corresponds to the sum of the widths of the individual beams. However, the beam width w1 + w2 could also be smaller or slightly larger.

[0103] Figure 7d The process of generating virtual pixels using two physical pixels is also explained.

[0104] Figure 4 Another top view of the embodiment shown in Figure 1 is illustrated, in which a combined transparent partial aperture region is employed. Here, three physical pixels A, B, and C of display unit 14 are used as an example. The light emitted by these three pixels, 161'', 162'', and 163'', passes through transparent partial aperture regions 70b with identical structures (i.e., completely identical). Since the different physical pixels A, B, and C are arranged in different positions, when the aperture units 70 are set to the same aperture configuration, their light rays 161'', 162'', and 163'' are projected onto different, in this case, relatively far apart, micromirror elements 12, 12', and 12''. Thus, when the micromirror elements 12, 12', and 12'' are tilted at an appropriate angle, they generate corresponding virtual pixels. This process is preferably performed simultaneously, as this reduces the switching frequency of the aperture units in time-division multiplexing. As a result, in a time-division multiplexing mode employing, for example, 100 different aperture settings (i.e., 100 different positions of the aperture region 70b shown in the transparent portion), when the portion of the aperture region 70b is in one of the positions, only 1 / 100 of the physical pixels in the display unit are active, similar to a sparse matrix.

[0105] Figure 5 A schematic diagram illustrating the effect of finite aperture size is shown in Figure 1 and... Figure 2 In the illustrated eyeglass display system, three apertures interact: the diameter of the pupil 11, the diameter 40 of the corresponding micromirror elements 12, 12', and 12'', and the exit aperture of the display unit 14 (determined in this example by the optical system 13). Figure 5 In the diagram, for clarity, the corresponding optical systems are drawn in series along the optical axis 42, and deflection is ignored. Depending on the line-of-sight direction and the distance between each aperture, different apertures can limit the diameter of the corresponding beam of emitted light. For example, Figure 5 The line of sight 44 shown at the top represents the limit of the maximum angle that can be formed through the pupil 11 when viewing the image with the diameter 40 of the mirror shown. However, the line of sight 44 does not fall on the aperture 41 of the optical system 13, so the display unit 14 cannot emit light into this angular range. On the other hand, the line of sight 43 has the maximum possible angle at which light emitted from the aperture of the optical system 13 is visible in the eye 10. However, the beam (shown here as parallel light) is crucial for enhancing the luminous intensity of the image and minimizing diffraction effects. A full beam 45 with rim rays 46 is as follows... Figure 5 As shown in the center. Figure 5The bottom shows a smaller beam 48, which, at a given angle corresponding to the edge ray 47, is limited by the size of the aperture 41. Therefore, it is advantageous to choose the largest possible aperture 41 for the optical system 13 to provide as many full-brightness viewing angles as possible for the virtual image. However, this conflicts with the need to minimize the size of the optical system 13 to save weight and achieve a slim AR glasses design. To resolve this technical conflict, multiple adjacent micromirror elements 12, 12', 12'' must be considered to ensure that the eye 10 can see a large, continuous image, i.e., an image without gaps due to missing virtual pixels. In this configuration, the smallest possible optical system aperture 41 is then chosen.

[0106] Figure 6 shows a top view of an exemplary embodiment of the aperture unit. Figure 6a As shown, the adjustable aperture unit 70 includes a reusable electrically adjustable or switchable total aperture region 70a. For this purpose, the switchable total aperture region 70a serves as the aperture, here with a diameter of 41. The switchable total aperture region 70a is switched to be transparent in a portion of the aperture region 70b and opaque in the remaining aperture region 70c. In this case, the size of the selected transparent portion of the aperture region 70b is such that the diameter of the light beam passing through it and thus the beam width of the light deflected at the deflection unit 17 is less than or equal to the diameter 40 of the reflecting surface 25 of the micromirror elements 12, 12', 12''. Since the diameter 41 is greater than the diameter 40, there exists a position in the transparent portion of the aperture region 70b and the beam position of the light deflected at the deflection unit 17 where the resulting beam falls only on a single micromirror element 12 and not partially on one or more adjacent micromirror elements 12', 12''.

[0107] In addition, such as Figure 6b As shown, if the transparent aperture region 70b, which is the transmission region, undergoes a progressive displacement, for example, along the spiral path 72, then for each viewing angle defined by the physical pixel, a position of the transparent aperture region 70b can be found such that the transmitted light falls only on a single micromirror element 12, and is thus deflected only by that micromirror element 12. The displacement of the transparent aperture region 70b can be continuous, or, as shown, at discrete positions such as 71, 71'. If the beam is directed only at a single micromirror element 12, the virtual image of the corresponding physical pixel is only at a surrounding position 100a ( Figure 2 It forms at location 100b, 100c, but not at any other surrounding locations 100b, 100c.

[0108] Figure 6cAn embodiment of the aperture unit is shown, in which liquid crystal elements constitute the total aperture region 70a. The size and position of the transparent aperture region 70b within the total aperture region 70a can be freely defined by a plurality of linear electrodes 70d, 70e, and 70f arranged back-to-back along the optical path and with different orientations. These electrodes thereby define the switchable pixel regions of the liquid crystal in the liquid crystal element. In the illustrated case, the transparent aperture region 70b is hexagonal in shape because the linear electrodes 70d, 70e, and 70f are oriented at a 120° angle to each other. This is particularly advantageous when the reflective surface 25 is hexagonal. Furthermore, this technical implementation is advantageous because transistors, as in liquid crystal displays, do not need to be placed within the total aperture region, since the electrodes 70d, 70e, and 70f extend to the edges and can make contact there.

[0109] from Figure 5 As can be seen from the relationship shown, it may be advantageous if the maximum beam intensity that each micromirror element 12 can handle is 50% of the available beam intensity for each physical pixel (i.e., less than the maximum beam width emitted by that pixel, especially when the light is parallel). This advantage stems from the fact that aperture 41 must be designed based on the size resulting from this constraint (see Figure 6). If aperture 41 is designed to support all beam widths or all beam diameters, then aperture 41 becomes relatively large. In this case, a sufficiently large aperture diameter 41 must be chosen to ensure that beam 44 can also be directed towards that aperture. Conversely, if the constraint is to support only beams with an intensity not exceeding 50% at the mirror diameter 40, a significantly smaller diameter 41 can be chosen. This also has an additional advantage, as truncating the aperture causes stronger diffraction, resulting in a reduction in the highest achievable resolution. The resulting reduction in virtual image intensity can be compensated for by increasing the light emission per unit area of ​​the display unit. Since the geometry of each pixel is known, appropriate compensation can be implemented, for example, using a calibrated pre-generated lookup table.

[0110] When designing the dimensions of micromirror elements 12, 12'', 12''' or their reflective surfaces 25, the following requirements can be selected: for a given effective exit aperture, when the line of sight is aligned with the beam directed toward the center of the micromirror element, at least 50% of the achievable intensity should always be achievable using only a single reflective surface 25. It is always important to ensure that a seamless virtual image can be generated. Gaps refer not only to missing virtual pixels but also to virtual pixels with lower intensity that cannot be adequately compensated for even by increasing the radiation intensity (i.e., the brightness of the virtual pixel deviates significantly from the given brightness distribution of the virtual image).

[0111] Other constraints specifically include:

[0112] - The relative arrangement geometry of the display unit 14 with respect to the deflection unit 17 and the eye 10, and / or

[0113] - The exit aperture of the display unit 14 is as small as possible, and / or

[0114] - The diffraction effect on the micromirror elements 12, 12', 12'' is minimized (more advantageous for larger reflecting surfaces 25), and / or

[0115] - Relative angular alignment of adjacent micromirror elements 12, 12', 12'' (a larger difference can reduce the number of artifacts such as ghosting when light partially illuminates adjacent micromirror elements 12, 12', 12''), and / or

[0116] - The step size of the adjustable aperture unit, and the spatial distance between the successive positions of the transparent partial aperture region 70b generated during time-division multiplexing / scanning (if the step size is small, a position of the partial aperture region 70b can always be found, thereby determining the beam position so that all light passing through the aperture unit 70 falls only on a single micromirror element 12, 12', 12''), and / or

[0117] - Maximum switching speed of the total aperture area 70a of aperture unit 70 (should reach a refresh rate of 60-120Hz).

[0118] Figure 7 shows exemplary illustrations of different beam positions on the corresponding micromirror arrays. Each sub-figure shows the beam projected onto the projection plane E ( Figure 3 The images show the positions of various related apertures 11, 40, and 41 on the projection plane, which substantially passes through micromirror elements 12, 12', and 12''. The projection 70a' of the total aperture region 70a has the largest diameter; the projection 11' of the pupil 11 with its central focus 11'' has the second largest diameter; the smallest diameter is that of the light position 70b' drawn as a projection of the transparent aperture region 70b, whose diameter corresponds to the beam diameter of light passing through the aperture unit 70. Projection 11' corresponds to a virtual pixel, while projections 70a' and 70b' correspond to the physical pixels of the display unit 14, respectively. For projection 70a', it is assumed that the total aperture region 70a is switched to a completely transparent state. These partial images show the corresponding situations for different virtual pixels (i.e., different viewing directions).

[0119] It should be noted here that the beam is depicted as circular. Due to the angular configuration, the actual shape is often elliptical, although beams of arbitrary shapes may occur depending on the aperture used. For simplicity and clarity, this aspect is omitted in the illustration, and circular geometry is used to illustrate the function.

[0120] Figure 7aA scenario of viewing a virtual pixel is illustrated, arranged such that viewpoint 11'' is substantially directly opposite the center of the illustrated micromirror element 12. If a larger transparent aperture region 70b is used (thus forming a beam position 70b' with a larger beam width), light passing through aperture unit 70 will not only (substantially) strike micromirror element 12, but also the six adjacent micromirror elements 12', 12''. Since micromirror elements 12, 12', 12'' are typically tilted at different angles, light deflected by micromirror elements 12, 12', 12'' will be projected in seven different spatial directions. Adjustable aperture unit 70 adjusts and reduces the position and size of the transparent aperture region 70b, i.e., the beam position 70b' and the beam path of the transmitted light, so that light is (substantially) deflected only by the central micromirror element 12.

[0121] Furthermore, by rapidly adjusting the position of the aperture region 70b of the transparent portion and thereby adjusting the beam position 70b', multiple virtual pixels can also be generated from the physical pixel. This corresponds to a time-division multiplexing method. In this case, for example in the illustrated scenario, if the angular orientation of the micromirror element 12' is appropriately adjusted, the aperture unit 70 can also guide light to the pupil along the viewing direction 11** with the pupil projection 11*. Figure 3 This is illustrated with an example.

[0122] Figure 7b This illustrates a scenario where the virtual pixel under consideration corresponds to viewpoint 11'', which is slightly off-center from the center of micromirror element 12. In this case, the beam position 70b' is chosen such that the associated beam can still be (essentially only) reflected into the eye by the central micromirror element 12. Therefore, the beam position is displaced relative to the viewing direction 11''.

[0123] Under the same line of sight, you can also choose such as Figure 7c The beam position 70b' shown is such that the light also falls on the adjacent micromirror elements 12', 12''. For example, with Figure 7b The situation is different; if it is maintained relative to the line of sight 11'' Figure 7a This situation may occur depending on the beam position. If such overlap between the light and the different micromirror elements 12, 12', 12'' is small, this may be irrelevant: this is because adjacent micromirror elements 12, 12', 12'' have different orientations, and typically only light from the central micromirror element 12 reaches the eye 11. However, in this case, the beam width perceived by the user is not only limited by the adjustable aperture unit (“adaptive aperture”), but is also truncated at the edge of the central micromirror element 12, thus effectively reducing the aperture. At beam position 70b', the effective beam width corresponding to the shadow sub-region of the beam surface is reduced, and this smaller aperture leads to a decrease in resolution. Therefore, as Figure 7bAs shown, adjusting the beam position relative to the line of sight 11'' is generally more advantageous.

[0124] However, there are also cases where this is not the case. Specifically, if the transparent aperture region 70b and its projection 70b' move between different locations with a discrete step length, it is impossible to select the ideal location of the transparent sub-aperture region for each (physical and / or virtual) pixel (e.g., Figure 5 (As shown in b), thus making it impossible to select an ideal beam position. As a technical compromise, one could choose, as shown in b... Figure 5 As shown in c, the beam position reduces the effective beam width, thus taking advantage of the fact that only a small number of discrete positions of the transparent aperture region 70b need to be scanned. A small number of scanned positions allows for higher virtual image brightness because switching the beam position 70b' by discretely moving the aperture region 70b takes time, during which no light can be transmitted, thus reducing the light intensity of the virtual image. However, the brighter the virtual image, the stronger its immersive effect, because only a sufficiently bright virtual image can prevent ambient light from being transmitted through it.

[0125] Corresponding to Figure 3 of Figure 7d A critical case is illustrated where the line of sight 11'' and the virtual pixel observed therefrom are precisely located in the middle of the two micromirror elements 12, 12'. Therefore, the observed virtual pixel can be assigned to two different physical pixels because the two micromirror elements 12, 12' can have different angular orientations, i.e., they can be tilted in different ways. The corresponding projection for each physical pixel is shown here: for the first physical pixel whose light is deflected by the first micromirror element 12, its projection / beam positions are 70a', 70b'; for the second physical pixel whose light is deflected by the second micromirror element 12', its projection / beam positions are 70a'', 70b''.

[0126] Depending on the specific requirements, in the case shown, either a single physical pixel can be used to form a virtual pixel, or two or more physical pixels can be used to form a single virtual pixel to enhance the strength of the virtual pixel. Figure 7e This illustrates a situation where the viewing direction 11'' and the virtual pixel viewed along that direction are precisely located in the center of the three micromirror elements 12, 12', and 12''. Figure 7d Similarly, the brightness of the virtual pixel can be enhanced by using the third physical pixel through the beam position 70b'' in the projection 70a''.

[0127] Figure 7fThe beam positions of multiple physical pixels on the shared micromirror element 12 are shown. Light from different pixels passes through the same transparent aperture region 70b through the aperture unit 70; however, since the light from each physical pixel leaves the display unit 14 at different angles, the corresponding beam positions 70b', 70b''...70b* on the shared micromirror element 12 are offset relative to each other. To enhance the brightness of the virtual image, it is advantageous to use multiple physical pixels simultaneously at a certain (scanning) position in the transparent aperture region 70b (and thus for the aperture unit 70). Figure 3 This example is shown. However, only those pixels that are fully incident on the common micromirror element 12 should be used (i.e., activated or turned on), or at least as shown. Figure 7c The pixels shown are those that significantly overlap with the shared micromirror element 12 so that they are imaged as a single virtual pixel in the pupil 11. Alternatively, physical pixels that are spaced far enough apart from each other so that they do not overlap in the virtual image can also be used. Figure 4 This example is shown.

[0128] Figure 8 illustrates another exemplary embodiment of the aperture element arranged on the deflection element. (Compared with Figure 1 and...) Figure 2 Unlike the embodiment shown, the aperture unit 70 here is arranged near the deflection unit 17, or as... Figure 8b The arrangement shown is internal to it. This enables an alternative multiplexing method. In this case, multiplexing is performed essentially near the plane of the micromirror elements 12, 12', 12''.

[0129] like Figure 8aAs shown, a static first polarizer 90 is inserted into the beam path to completely polarize the light incident on the micromirror elements 12, 12', 12''. Furthermore, a birefringent pixel-switchable (pixelated) liquid crystal element 91 is used to electrically switch the polarization state, involving only two states. With the aid of an additional static polarizer 92, the segments of the segmented liquid crystal 91, similar to a liquid crystal display, can be switched so that some segments 93, 93', 93'' change their polarization state, while other segments 94 retain their polarization state. Therefore, light passing through the polarization-changed segments 93, 93', 93'' and incident on the display unit 14 is ultimately visible to the user, while light passing through the polarization-unchanged segments 94 and incident on the display unit 14 is ultimately invisible to the user. Thus, the liquid crystal element 91, together with the second polarizing element 92, defines the transparent portion aperture region 70b and the opaque remaining aperture region 70c. The dimensions of segments 93, 93', 93'', and 94 of the liquid crystal element 91 are selected such that the light passing through is directed only towards one of the micromirror elements 12, 12', and 12''. Depending on the diameter 41 of the exit aperture, multiple segments (e.g., 93, 93', 93'') can be switched simultaneously to change the polarization, thereby making the corresponding portion of the aperture region 70b transparent. Since only one polarizing filter is placed between the eye 10 and the natural environment, the eye 10 can see the natural environment 100 regardless of the switching state of the liquid crystal element 91, but the light intensity will be reduced by 50%, similar to sunglasses. Depending on the polarization state (linear or circular polarization) configuration, it may be necessary to place a static waveplate between the second polarizer 92 and the micromirror elements 12, 12', and 12'' so that the reflected light can pass through the polarizing filter 92 again.

[0130] Figure 8b This is illustrated in more detail. In this example, display unit 14 emits light or beams 161'', 162'', and 163'' with s-polarization and p-polarization states. In the first polarization unit 90, beams 161'', 162'', and 163'' are s-polarized. In the transparent aperture region 70b of aperture unit 70, the polarization state of the light is changed by the liquid crystal element 92, while in the opaque aperture region 70b of aperture unit 70, the polarization state of the light remains unchanged.

[0131] In this case, beams 161'' and 162'' are p-polarized, and therefore can pass through aperture unit 70 and be directed towards micromirror elements 12 and 12'. Beam 163'', which remains s-polarized, is absorbed by the second polarizing element 92 and cannot pass through aperture unit 70. Beams 161'' and 162'' are reflected by micromirror element 12 to form beams 161 and 162, which are visible to the eye 10 and thus to the user; the same applies to ambient light or ambient beams 100a and 100b.

[0132] Figure 8c An embodiment without the second polarizing element 92 is shown, wherein an aperture unit 70 containing a liquid crystal element 91 and a first polarizing element 90 is arranged nearby, specifically in the deflection unit 17. In this case, the liquid crystal element 91 is designed as a switchable λ / 4 waveplate, thereby reversing the polarization state of circularly polarized light.

[0133] Light beams 161'' and 162'' emitted by display unit 14 in p+s polarized form pass through the first polarizing element 90 and liquid crystal element 91 before being deflected by micromirror elements 12 and 12'. During this process, beams 161'' and 162'' are first linearly polarized by the first polarizing element 90, in this case, s-polarized. Beam 161'' passing through the transparent aperture region 70b is converted into light with circular polarization characteristics, in this case, l-polarized light. Beam 162'' passing through the opaque remaining aperture region 70c is converted into light with different circular polarization characteristics, in this case, r-polarized light.

[0134] Upon reflection by micromirror elements 12 and 12', the circular polarization state is reversed. As a result, only light 161'' from display unit 14 that passes through the transparent aperture region 70b can pass through polarizing element 90 and become visible. Light 162'', which only passes through the opaque remaining aperture region 70c, has a polarization state that does not match that of polarizing element 90 and is therefore absorbed by it. Light from ambient positions 100a and 100b is not significantly affected by liquid crystal element 91; only its overall intensity is reduced by polarizing element 90, similar to the effect of sunglasses. Figure 9 A plan view of an exemplary embodiment of a glasses display system with an additional focusing unit is shown, which in this example also has vision correction functionality. The additional focusing unit 13'' functions as an adaptive optics system, and its focus is adjusted by a control unit 110. For example, the focus of the virtual image can be set at infinity (beam path / beam 112) or at a finite distance (beam path / beam 111). This resolves the convergence-accommodation conflict problem. Different sharpness planes can even be set within a single virtual image if the focus adjustment speed is faster than the refresh rate.

[0135] By adding another lens element 13''' between the deflection unit 17 and the environment 100, vision correction functionality can be integrated here with minimal effort. In this case, the control unit 110 must take the characteristics of this element into account accordingly.

[0136] Figure 10Another embodiment of a glasses display system under glare conditions is shown. In this case, the eyes 10'' of another person 143 may be looking at the display unit 14 (the optical system 13 is currently designed as part of the display unit 14). Therefore, there is a risk that the person 143 may be blinded by glare. Since the glasses display system 1 in this case uses cameras 142, 142' to determine, for example, their orientation in space, these cameras 142, 142' and / or other sensor technologies such as eye-tracking device 15 can be used to measure the user's eye position 10, 10'. This also makes it possible to calculate the angular range 145 at which the emitted light would glare the person 143 opposite. Thus, the control unit of the display unit 14 can be informed of the glare risk within the angular range 145 and accordingly, for example, prevent any content from being displayed in that area, or display content only at a reduced intensity.

[0137] Figure 11 illustrates another exemplary embodiment of the glasses display system. For example... Figure 11a As shown, the eyeglass display system 1 in this example has a deflection unit 17, which includes multiple micromirror elements 12, 12', 12'', arranged over a large area corresponding to the field of vision of conventional eyeglasses. Furthermore, Figure 11b An internal view of a deflection unit 17 comprising multiple micromirror elements 12, 12', and 12'' is shown. Adjacent micromirror elements 12 and 12' are used as an example, and these micromirror elements overlap. In the example shown, the micromirror elements 12, 12', and 12'' are staggered along the y-direction and have different dimensions. The reflective surface area of ​​micromirror element 12'' is larger than that of micromirror element 12', and the reflective surface area of ​​micromirror element 12' is larger than that of micromirror element 12.

[0138] Figure 12 A further schematic diagram of an exemplary embodiment of the glasses display system is shown. As in the described embodiment, light beams 161'', 162'' generated by display unit 14 are deflected and directed into the corresponding eye 10 via micromirror elements 12, 12'', 12'''. Each light beam 161, 162 directed into the eye 10 corresponds to a pixel of the virtual (AR) image. Therefore, the eye 10 is able to perceive the angular range of the virtual image associated with each micromirror element 12, 12'', 12''' via each micromirror element 12, 12'', 12'''.

[0139] Furthermore, as is well known, the eyeglass display system 1 includes a display unit 14 and an adjustable aperture unit 70, and in this case, it also includes an optical system 13 located between the adjustable aperture unit 70 and the display unit 14. In this embodiment, it also includes a projector optical system 130 located between the adjustable aperture unit 70 and the deflection unit 17. To illustrate this more clearly, Figure 12The display unit 14, adjustable aperture unit 70, optical system 13 and projector optical system 130 are shown in magnified form, and the common optical axis O at any position is shown.

[0140] Light rays 161'' and 162'' reflected by micromirror elements 12, 12'', and 12''' originate from display unit 14 and pass through projector optical system 130. Figure 12 The image schematically shows three lenses entering the eye 10. The projector optics 130 at least substantially projects an image onto the focal plane F1, while the display unit 14 or its display is not located on this focal plane. At this focal plane, the angular range associated with the corresponding micromirror elements 12, 12'', 12''' results in overlapping areas, such as... Figures 13a-13e As shown in more detail, five regions 120a-120e are exemplary shown on the focal plane F1, each of which overlaps with its nearest neighbor. In the presence of overlapping regions, a physical pixel of display unit 14 can be visible to eye 10 through more than one micromirror element 12, 12'', 12'''.

[0141] The projector optical system 130 is arranged and / or configured within the eyeglass display system 1 such that, according to the imaging formula... Another focal plane provides a clear image of the micromirror elements 12, 12'', 12'''. An adjustable aperture unit 70 is arranged at this additional focal plane. The adjustable aperture unit 70 is advantageously designed such that its pixels, which can switch between transparent and opaque states, at least substantially correspond to the imaging areas of the corresponding associated micromirror elements 12, 12'', 12'''.

[0142] Optical system 13 (arranged here between adjustable aperture unit 70 and display unit 14) is advantageously configured to image the physical pixels of display unit 14, such that the light beam generated by the respective physical pixels can be perceived by eye 10 with the desired clarity. Accordingly, optical system 13 may also include or be the aforementioned additional focusing unit 13''. Alternatively, optical system 13 may also be arranged in the optical path between adaptive aperture unit 70 and projector optical system 130. For example, adaptive aperture unit 70 may thus also be arranged in the optical path between display unit 14 and optical system 13, which is implemented as a microlens array as described below.

[0143] As shown in the schematic diagram in Figure 13, the multiplexing method with the configuration shown enables the utilization of physical pixels to achieve a wide range of redundancies by employing different optical systems.

[0144] Figure 13aAn embodiment is shown in which a single region of display unit 14 corresponds to all regions 120a-120e of the virtual image, and each region is mapped to a single micromirror element. Therefore, in pure time-division multiplexing, at a predetermined time, for example, image content 140a is allocated to region 120a of the virtual image via aperture pixel 70-1 switched to a transparent state. At this time, other aperture pixels 70-2 to 70-5 are opaque. At a subsequent time, for example, image content 140b that occupies the same area on the screen of display unit 14 as the previous image content 140a can be allocated to region 120b of the virtual image via aperture pixel 70-2 switched to a transparent state, i.e., displayed there, while the remaining aperture pixels 70-1 and 70-3 to 70-5 remain opaque, and so on. Aperture pixels 70-1…70-5 may correspond to the aforementioned segments 93, 93', 93'', 94, and / or vice versa. Aperture pixels 70-1...70-5 and segments 93, 93', 93'', 94 can also correspond to switchable partial aperture regions 70a.

[0145] Alternatively, the optical system 13 may map mutually offset and / or scaled (in this case, local) regions on the display unit 14 onto corresponding regions 120a-120e of the virtual image. Figure 13b This case is shown for offset image content 140a-140e.

[0146] Another possibility is to specify the aperture pixel group 70-1...70-5 of the display surface sub-region of the shared display unit 14. Figure 13c This is illustrated, and its advantage lies in the fact that multiple aperture pixels 70-1...70-5, that is, the individual pixels in aperture pixels 70-1...70-5, can be turned on simultaneously without causing overlap. Due to the parallel use of the resulting aperture units 70, a sufficiently bright virtual image can be generated even if the light intensity of the display unit 14 is low, compared to the case where only aperture pixels 70-1...70-5 are used for pure time-division multiplexing.

[0147] exist Figure 13d In the illustrated case, multiplexing is not required. The optical system 13 includes, or in this case, a microlens array comprising multiple microlens elements arranged in parallel along the beam path. These microlens elements 13a-13e are designed to map spatially disjoint image content 140a-140e onto the display of the display unit 14. This allows all image content to be displayed simultaneously without multiplexing. Alternatively, a display with a lower maximum brightness, such as OLED technology, can be used, which cannot achieve extremely high intensity for a short period like µLED displays.

[0148] at last, Figure 13eThe diagram illustrates the integration of the adjustable aperture unit 70 into the optical system 13. In this case, the adjustable aperture unit 70 is arranged on the extended focal plane, just like the optical system 13.

Claims

1. A glasses display system (1) for displaying a virtual image within a user's field of vision, comprising: - A display unit (14) for emitting light (163'', 161'', 162'') along the emission direction as computer-generated image information; and - A deflection unit (17) for deflecting the light (163'', 161'', 162'') emitted by the display unit (14) as computer-generated image information into the user's eye (10), and including a plurality of micromirror elements (12, 12', 12''), each of which can be tilted within a support structure, and each of the micromirror elements (12, 12', 12'') includes at least one reflective surface (25) for redirecting the light (163'', 161'', 162'') emitted by the display unit (14) as computer-generated image information. Its features are, - An adjustable aperture unit (70), which is arranged in the optical path of the light (163'', 161'', 162'') between the display unit (14) and the tiltable micromirror elements (12, 12', 12''), can be adjusted by a control signal and is configured to adjust at least one beam position (70b', 70b'', 70b*) of the light reflected at the reflective surface (25) of the tiltable micromirror elements (12, 12', 12'') according to the control signal.

2. The eyeglass display system (1) according to the preceding claims. Its features are, The adjustable aperture unit is arranged in the optical path from the display unit (14) to the deflection unit (17), specifically between the optical system (13, 130) of the eyeglass display system (1), particularly the projector optical system (130) and / or the optical system (13) designed as a microlens array and the display unit (14).

3. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The adjustable aperture unit (70) is configured to adjust the position of at least one beam (70b', 70b'', 70b*) by adjusting at least one position of a corresponding transparent portion aperture region (70b) within the total aperture region (70a) that can become transparent according to the control signal.

4. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The adjustable aperture unit (70) is configured, according to the control signal, to adjust, in addition to adjusting the beam position (70b', 70b'', 70b*), the beam width associated with one of the beam positions (70b', 70b'', 70b*) for the light deflected at the reflective surface (25) of the tiltable micromirror element (12, 12', 12'').

5. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The adjustable aperture unit (70) is configured to adjust the beam width such that it is smaller than the diameter (40) of one or more reflective surfaces (25) of the corresponding irradiated micromirror element.

6. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The adjustable aperture unit (70) is configured to adjust the position (70b', 70b'', 70b*) and the beam width such that most of the light (163'', 161'', 162'') passing through the adjustable aperture unit (70) just irradiates the reflective surface (25) of one of the micromirror elements (12, 12', 12''), particularly in conjunction with the portion of the display unit to deactivate.

7. The eyeglass display system (1) according to any one of the preceding claims. Its features are, - A refresh rate was specified for the computer-generated image information; and - The aperture unit (70) is configured to adjust the beam width and / or beam position (70b', 70b'', 70b*) multiple times within a time interval specified by the refresh rate for the image.

8. The eyeglass display system (1) according to the preceding claims. Its features are, The aperture unit (70) is configured to adjust the beam positions (70b', 70b'', 70b*) to at least 3, particularly at least 7, preferably at least 10, and most preferably at least 200 different beam positions within a time interval specified by the refresh rate for the image.

9. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The aperture unit (70) is configured to simultaneously make several different, preferably three or more different, particularly non-adjacent partial aperture regions (70b) transparent within the total aperture region (70a) of the aperture unit (70), which can switch between transparent and / or opaque states. Preferably, the partial aperture regions (70b) that can be transparent at the same time belong to different groups of partial aperture regions (70b), and the partial aperture regions (70b) in the different groups of partial aperture regions (70b) are assigned to different physical pixels of the display unit (14).

10. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The aperture unit (70) is configured to adjust the beam width and / or beam position (70b', 70b'', 70b*) at a frequency of at least 100 Hz, preferably at least 1000 Hz, and most preferably at least 20 kHz.

11. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The aperture unit (70) includes or is a pixelated liquid crystal element (91).

12. The eyeglass display system (1) according to the preceding claims. Its features are, - The pixelated liquid crystal element (91) is or includes a switchable waveguide; - The aperture unit (70) includes, in addition to the liquid crystal element, a first static polarization element (90), which transmits first polarized light and is arranged in the optical path between the display unit (14) and the pixelated liquid crystal element (91), preferably at the display unit (14) or at the deflection unit (17); and Specifically, the aperture unit (70) includes, in addition to the liquid crystal element, a second static polarization element (92) that transmits second polarized light different from the first polarized light, and is arranged between the pixelated liquid crystal element (91) and the micromirror elements (12, 12', 12''), preferably at the deflection unit (17); and - The adjustable aperture unit (70) is configured to adjust the beam position (70b', 70b'', 70b*) by adjusting the polarization conversion characteristics of the total aperture region (70a) to convert the polarization state in the transparent aperture region (70b) while maintaining the polarization state unchanged in the remaining regions of the total aperture region (70a) that are different from the transparent aperture region (70b), and vice versa.

13. The eyeglass display system (1) according to any one of the preceding claims. Its features are, - The control unit is configured to control the adjustable aperture unit (70) via the control signal and to control the display unit (14) via another control signal according to time-division multiplexing, in which at least two virtual pixels of the virtual image are assigned to a physical pixel of the display unit (14).

14. The eyeglass display system (1) according to any one of the preceding claims. Its features are, An additional focusing unit, particularly comprising or consisting of an electrically adjustable liquid-controlled lens, is arranged in or on the display unit (14), wherein the additional focusing unit is configured to move the focal plane of the light emitted by the display unit (14) according to an additional control signal.

15. The eyeglass display system (1) according to any one of the preceding claims. Its features are, The display unit (14) is configured to adjust the intensity of light emitted to the corresponding beam position (70b', 70b'', 70b*) for each beam position (70b', 70b'', 70b*) adjusted by the aperture unit (70), in particular, to match the luminous flux of different beam positions (70b', 70b'', 70b*) arriving sequentially or simultaneously.

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