An eyeglass display system for displaying virtual images within a user's field of view using non-visible micro-mirror elements

Abstract

The present invention relates to an eyeglass display system (1) for displaying virtual images within a user's field of vision, comprising a display unit (14) for emitting light rays (163", 161", 162") as computer-generated image information along an emission direction, and a deflection unit (17) for deflecting the light rays (163", 161", 162") emitted by the display unit (14) as computer-generated image information to the user's eyes (10); the system further comprises a plurality of micromirror elements (12, 12', 12") tiltable in a support structure (200), each micromirror element having a reflective surface (25) for deflecting the light rays (163", 161", 162") emitted by the display unit (14) as computer-generated image information; wherein the micromirror elements (12, 12', 12") and the support structure (200) are arranged within a sealed housing element (17a) filled with liquid (23) of the deflection unit (17) to provide an eyeglass display system (1) with enhanced immersion.

Description

Cross-references to related applications

[0001] This application claims priority to DE 10 2024 101 597.7, filed on January 19, 2024, and DE 10 2024 101 596.9, filed on January 19, 2024, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0002] This invention relates to an eyeglass display system for displaying virtual images within a user's field of vision, 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 toward the user's eyes. The system also includes a plurality of micromirror elements that can be tilted in a support structure, each micromirror element having a reflective surface for deflecting the light emitted by the display unit as computer-generated image information. Background Technology

[0003] Augmented reality (AR) glasses, also known as "AR glasses," are eyewear systems that display virtual images within a user's field of vision. They overlay virtual objects as virtual images onto the user's natural environment, thus virtually enhancing the field of vision. By displaying stereoscopic images, these virtual objects can be freely positioned in space. Therefore, providing the largest possible augmented field of vision and a high (viewing angle) resolution display is beneficial. This creates immersion by ensuring the continuous visibility of virtual objects and their consistent position in space, making the virtual objects feel like physical objects. The weight of such glasses particularly affects immersion, potentially causing an unnatural sensation when the user's head moves. The so-called convergence accommodation problem is also a well-known phenomenon that weakens immersion.

[0004] All 3D display devices that display 3D objects using two stereoscopic images suffer from the problem of vergence accommodation. In this process, 3D information—that is, the distance between the object and the eye—is determined by the offset stereoscopic image. This distance conflicts with the distance at which the eye focuses to see the image clearly. A similar problem arises in augmented reality applications: how to integrate virtual 3D objects into a real 3D environment. If the focusing distance of the stereoscopic image is inconsistent with the focusing distance of the real environment, then even if the real and virtual scenes are spatially fixed in the same location within the environment, it is impossible to observe both scenes simultaneously.

[0005] 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 shrink the required optical components to a sufficiently small size to meet the shape and weight standards of ordinary eyeglasses remains a technically unsolved problem. Oversized eyeglasses technically limit their potential applications, as people may not be comfortable wearing such a large product on their face in various everyday situations. Excessive weight limits the wearing time of augmented reality glasses. Exemplary solutions are described in DE 10 2020 206 392 A1 or DE 10 2023 101777 A1.

[0006] US Patent 10,623,707 B2 describes augmented reality glasses that provide a high-resolution image in the central fovea and project a lower-resolution image area in the peripheral field of vision. To this end, an eye-tracking sensor measures the gaze direction of the eyes and adjusts the projection optics accordingly.

[0007] Augmented reality glasses are described in US 2020 0186761 A1 and US 11 422 274 B2, which can adjust the focal length of the augmented reality optics system to display objects at different distances. Therefore, this paper discloses a technical solution to the problem of visual convergence accommodation. US 2020 0186761 A1 also includes an eye-tracking module for measuring eye convergence parameters. Furthermore, it is suggested that these measurements be used to track eye movements, thereby enabling eye tracking for different eye positions.

[0008] Therefore, the technical challenge is to provide a more immersive glasses display system, in particular to minimize weight, achieve the largest possible virtual augmented field of view, and solve typical problems of augmented reality glasses, such as the visual convergence accommodation problem and / or vision correction problem. Summary of the Invention

[0009] This challenge is addressed by the subject matter described in the independent claims. Preferred embodiments can be derived from the dependent claims, the specification, and the drawings.

[0010] One aspect relates to a glasses display system for displaying virtual images within a user's field of vision, 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 toward the user's eyes. The emission direction is preferably at least substantially oriented toward the user's field of vision (forward, so that light is projected into the field of vision), and the deflection unit comprises at least the micromirror elements described below and is arranged within the user's field of vision (in front of one or both of the user's eyes) to deflect (backward) the light back to one or both of the user's eyes.

[0011] The deflection unit comprises multiple tiltable micromirror elements, each arranged within a support structure. Each micromirror element has a reflective surface used to deflect light emitted by the display unit as computer-generated image information toward the user's eye. In this case, the reflective surface can transmit ambient light from the environment in front of the user's field of vision, directed toward the eyes. Therefore, these reflective surfaces can be considered as translucent mirrors. Thus, a single micromirror element can also have multiple mirrors. This is the case, for example, when each micromirror element comprises a coated substrate (especially a glass substrate). In this case, one side of the substrate can be coated, while the other side can be uncoated. Therefore, two reflections may occur, with one side acting as a reflective surface and the other as another.

[0012] On the coated side, reflectivity can be adjusted (technically) in a desired manner by employing a suitable coating (designed for the desired optical effect); on the uncoated side, reflection is based on Fresnel reflection, which arises from the change in refractive index between the substrate and the surrounding environment (e.g., the liquid in the housing element described below). For micromirror elements immersed in liquid, the latter type of reflection is typically very weak because the refractive index of the glass commonly used as the substrate is very close to that of the liquid. Furthermore, the other side of the substrate can also have a coating. For example, this could be a stress-resistant coating, which, unlike the coating designed to produce the optical effect, is designed to compensate for the stresses generated between the substrate and its coating—stresses that could cause warping of the substrate. This technically adjusted reflective surface can also be located within the volume of the micromirror element, so there may be a total of three reflective surfaces. In this case, two additional reflections will occur at the interface between the micromirror element and the surrounding environment (ideally the liquid). The additional reflections are likely minor, and therefore much weaker than the (primary) reflection on the technically adjusted reflective surface. For example, the intensity of the additional reflections may be one or more orders of magnitude weaker than the primary reflection. Additionally, a coating designed to achieve the desired optical effect can be applied to one and the other sides. In this way, the (primary) reflections on the front and back sides of the substrate can be adjusted using technical means, that is, its optical properties can be modified. Multiple layers can also be coated on one side of the substrate, so each micromirror element can have multiple reflective surfaces.

[0013] The term "multiple micromirrors" as used herein can be understood to mean at least 20, at least 100, or at least 1,000 micromirrors. As is typical with micromirrors, these reflective surfaces are very small, for example, less than 100 mm² or less than 20 mm². Because the micromirrors are movably mounted within the support structure, the angular positioning of their reflective surfaces can be adjusted in two dimensions. Therefore, the light emitted by the display unit (i.e., the light from the display unit) can be deflected into the eye or pupil even when the eye is in different directions and / or positions. Since the deflection unit is at least partially (i.e., partially or completely), particularly its micromirror elements, located in the optical path that guides ambient light from the user's field of vision to the user's eye, a virtual image corresponding to computer-generated image information can overlap with surrounding real objects in the user's field of vision, because these micromirror elements (as is necessary for augmented reality glasses) are at least partially transparent to light from the environment (ambient light). To achieve better immersion and present the largest possible and most artifact-free virtual image, the deflection unit and / or display unit will be controlled according to the eye's orientation, for example, through a control unit described below.

[0014] Preferably, all or at least most (preferably almost all) of the micromirror elements (particularly always and / or primarily) are positioned, at least in the standard operating mode of the eyeglass display system, in a manner that ensures only light from the display unit can be directed to the user's eyes. This angular positioning can be set regardless of whether the micromirror elements are illuminated by the display unit in the standard operating mode. The advantage of this is that light sources from other locations will not produce visible reflections in the eye. This avoids bothersome light reflections that manifest as ghosting. This is particularly advantageous in outdoor applications, where sunlight, as a very bright light source, can cause uncomfortable glare. Another advantage is that a high-reflectivity coating (e.g., a semi-transparent coating) can be selected for the reflective surface of the micromirror elements, as it will not exacerbate unwanted glare in the eyes even with high reflectivity.

[0015] Furthermore, a power-saving operating mode can be set for the glasses display system. In this mode, micromirror elements (specifically, those not illuminated by the display unit) will be adjusted to a preset stationary position. In this stationary position, actuators containing one or more of the actuator elements described below may be completely or partially disabled. For example, when no virtual image is displayed, or when a large or prolonged black area appears in the virtual image, the micromirror elements can be adjusted to a stationary position. Preferably, the micromirror elements will only move again when they are illuminated by the display unit again. The stationary position of the micromirror elements can be preset to correspond to the stationary state of their respective eyes. Therefore, in essence, in the stationary position of the micromirror elements, when the user's eyes are stationary, only the light emitted by the display unit is directed to the user's eyes. However, the reflection conditions are not met at this time, which may cause interference reflections of light coupled from the rear. Although poor reflections of ambient light may cause visual artifacts in some cases, studies have shown that people usually keep their eyes in the aforementioned stationary state or neutral gaze position, thus minimizing the possibility of artifacts. Therefore, in general, it is advantageous to select the stationary position of the micromirror element based on the stationary state of the eye, so that the reflection conditions of the projector's output aperture can be met most of the time, even when the actuator is closed.

[0016] As an alternative or supplementary solution, a high-quality operating mode can be set, in which the angular positioning of the micromirror elements is continuously performed, meaning the micromirror elements always follow eye movements (e.g., even when no virtual image is displayed, or when there are large or prolonged black areas in the virtual image). The glasses display system can also be designed with sensor devices (e.g., camera sensors) capable of detecting and / or analyzing the surrounding environment (e.g., current lighting conditions), and an automatic switching mechanism designed to automatically switch between different operating modes based on one or more preset switching criteria. For example, the probability of bright spots appearing (which can easily cause bothersome reflections) as assessed by the sensor device can be set as the switching criterion; 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 surrounding environment can also be collected and analyzed based on location data; for example, the probability of bright spots appearing is generally higher when using the glasses display system outdoors than indoors. By setting appropriate control schemes, power consumption and immersion levels can be optimized.

[0017] The display unit may include one or more preferably planar screen elements (“displays”) to generate light, or it may include one or more (laser) projection elements. In particular, the display unit may be a stereoscopic display unit suitable for generating virtual stereoscopic images within the field of view. For this purpose, the stereoscopic display unit may have two screen elements or two (laser) projection elements, each corresponding to one of the user's two eyes. For example, the screen elements or (laser) projector elements may be arranged on a temple unit of the eyeglass display system, located to the user's side. In this process, it should be ensured as much as possible that light from the light-emitting pixel elements of the display unit illuminates only one micromirror element and cannot be observed simultaneously through one or more adjacent micromirror elements. This is because, in the latter case, the same pixel information would be perceived in two different spatial directions, i.e., as two different virtual pixels (pixels of the virtual image), since adjacent micromirror elements are typically tilted relative to each other at a non-zero angle, meaning they have different orientations.

[0018] In one embodiment, the display unit can be designed to have a light-emitting display screen (particularly a so-called "microdisplay") and a microlens device, i.e., a so-called "microlens array." This microlens device has multiple microlens elements arranged in parallel (rather than in series) in the optical path from the light-emitting display screen of the display unit to the exit aperture of the display unit. The diameter of such microlens elements can be, for example, less than 1000 μm, preferably less than 500 μm, and / or greater than 50 μm. Preferably, the display unit also has a projection optics system with multiple optical lenses (particularly achromatic). Here, the projection optics system is arranged in the optical path between the microlens device and the exit aperture. In particular, the projection optics system is designed to guide only the light from each microlens element in the microlens device to a single microlens element. Therefore, each microlens element used in the operation of the eyeglass display system corresponds precisely to one microlens element. Thus, the optical imaging achieved by the projection optics system ensures that the light emitted from the microlens element can only be seen or perceived through one microlens. The advantage of this approach is that no multiplexing is required (or, when using the adjustable aperture unit described below, only slight multiplexing is needed). This means that all (or, in the case of the adjustable aperture unit, most) micromirror elements can simultaneously display virtual pixels. Therefore, unlike multiplexing schemes, lower light intensity is sufficient for the emitting pixel elements, as these elements can remain on / active for the entire duration of a single frame, not just for a very short period. Thus, lower-brightness display technologies, such as organic light-emitting diodes (OLEDs), can be used.

[0019] If an achromatic projection optical system is used, its corresponding optical imaging is also achromatic. Therefore, for the three primary colors of the display unit, the corresponding imaging from the microlens element to the micromirror element is at least substantially independent of wavelength. The three primary colors are typically red, green, and blue. The technical goal is to ensure that the field of view of each micromirror element is limited to one microlens element, thereby avoiding crosstalk between image contents.

[0020] Therefore, it is preferable to allocate an independent pixel element region for each microlens element on the light-emitting display screen. The light emitted by the light-emitting pixel element in this pixel element region is imaged through only one microlens element. The microlens elements and the projection optics system can be matched to each other so that, in addition to imaging the plane of the microlens element onto the plane of the micromirror element, a clear image of the light-emitting pixel element can also be projected onto the user's eye, or onto the "eye zone" corresponding to the eye position. These planes can also be curved surfaces or other two-dimensional manifolds in three-dimensional space. In this case, the above adjustments are preferably made under the following boundary condition: the virtual image achieves maximum clarity when the eye is directly facing the center of the corresponding micromirror element. In this orientation, the human eye can observe the corresponding micromirror element with optimal imaging capability. Since the imaging capability of the human eye decreases rapidly and significantly to the sides, the resulting decrease in image quality is not a problem for micromirror elements located on either side of the central line of sight. If the display unit is located inside or on the temple of the eyeglass display system, there is a relative tilt between the plane of the microlens element and the plane of the micromirror element. Therefore, a SAM optical system can be selected for the projection optics system. However, in principle, the optical system can be adjusted according to the different geometric arrangements of the display unit relative to the deflection unit.

[0021] In another embodiment, the microlens device is arranged to be movable relative to the light-emitting display screen via a focusing actuator, particularly translational. This is particularly advantageous because the focal length of the microlens device is relatively small, for example, less than 2 mm, preferably less than 1 mm. Therefore, to obtain a better-focused virtual image, only a very small amount of movement / displacement is required, for example, less than 2 mm, preferably less than 1 mm. For example, the focal plane can be moved quickly in this way when the user's gaze jumps from one virtual object to another. This alleviates the problem of visual convergence accommodation, thereby enhancing immersion.

[0022] In another embodiment, not all micromirror elements correspond to a single microlens element. Therefore, the number of micromirror elements may exceed the number of microlens elements. Accordingly, micromirror elements not paired with any microlens element will be directly imaged onto the light-emitting display screen via the projection optics system; conversely, the corresponding pixel element area of ​​the light-emitting display screen will also be imaged onto the micromirror elements not paired with any microlens element. Preferably, compared to micromirror elements paired with microlens elements, the micromirror elements not paired with any microlens element are positioned closer to the outer edge of the field of view, i.e., closer to the corresponding adjacent temple of the eyeglass display system. This is advantageous because the angular distance between adjacent micromirror elements typically decreases gradually in the nasal region of the field of view, which increases the risk of unintended crosstalk between micromirror elements. This is because the distance between the micromirror element and the display unit is much greater in the temple region than in the bridge region. In this case, the angular distance is determined by the difference in tilt angles between adjacent micromirror elements.

[0023] In another embodiment, the microlens device is designed to correct and / or compensate for the dispersion of light emitted by the light-emitting display. This can be achieved, for example, by adding a diffraction structure to the microlens device, and / or through mutually tilted (external) interfaces. Such mutually tilted interfaces can compensate for dispersion like a prism effect. This improves image quality, thereby enhancing immersion.

[0024] In one embodiment, the micromirror element and support structure can be designed to be arranged within a liquid-filled and sealed housing element of the deflection unit. This housing element can be positioned in front of the user's eyes similarly to the lenses of ordinary eyeglasses. Accordingly, 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 the liquid. The housing element has corresponding oil- and / or water-resistant properties and is made of a material that is (at least substantially) transparent to ambient light and the light from the display unit, as is the case with conventional eyeglass lenses. The micromirror element and support structure are also preferably made of a transparent material, as will be explained again below.

[0025] The liquid bath containing the micromirrors and support structure acts as a damper, suppressing vibrations and consequently minimizing unwanted small, rapid changes in the angular positioning of the reflective surface. This is advantageous because the eye makes jumpy movements at speeds up to 1000° per second before coming to a standstill. Furthermore, by adding liquid at the material transition point—the interface between the liquid and the micromirrors or support structure—the difference in refractive index can be reduced. This reduces both Fresnel reflections and other refractive effects. By reducing reflections and various effects, the visibility of elements or structures immersed in the liquid bath can be decreased, as is the case with glass components submerged in water. This avoids artifacts in the field of vision that could disrupt the user's immersion and allows the micromirror array ("micromirror array") to be placed directly in front of the user's eyes, within their field of vision. However, only with a micromirror array can a large virtual expansion of the field of vision be achieved at a higher (angular) resolution, making it a prerequisite for realizing immersive glasses display systems with sizes close to those of commercially available ordinary glasses.

[0026] In another embodiment, as described above regarding the housing element, the micromirror element and / or support structure and / or other components surrounded by or adjacent to the liquid (e.g., one side of the housing element facing the interior space) are all transparent to ambient light (at least substantially) from within the user's field of vision. The micromirror element and / or support structure and / or other components are all made of, or contain, a corresponding transparent material having a first refractive index. In particular, the housing element and / or micromirror element and / or support structure and / or other components can be made of the same material, which helps to match their optical properties.

[0027] The liquid for ambient light is also (at least substantially) transparent and has a modified second refractive index to minimize its deviation from the first refractive index. Specifically, at a given temperature value (preferably within the temperature range described below), the second refractive index can be equal to the first refractive index for at least one wavelength in the green wavelength range. Therefore, a liquid should be selected such that the deviation between the second and first refractive indices does not exceed a predetermined limit (e.g., 0.005) within a predetermined wavelength range (e.g., 400 nm–700 nm) and / or a predetermined temperature range (e.g., 0°–30°). In this process, the liquid can also be optimized for one or more sub-ranges within the corresponding range, for example, within a wavelength range of 540 nm ± 30 nm and / or a temperature range of 21° ± 2°, where its second refractive index is particularly close to the first refractive index. Similarity within the green wavelength range (520 nm–565 nm) is particularly advantageous because studies have shown that the human eye has a higher resolution for artifacts in the green wavelength range compared to the red or blue wavelength ranges. Within a sub-range, particularly the green wavelength range, a relatively small maximum deviation threshold, such as 0.002, can be set accordingly. Preferably, within the green wavelength range, the refractive index curves (with wavelength as the horizontal axis) of the liquid overlap with those of the first material. Such "refractive index-matched liquids" are commercially available and possess the desired characteristics. Therefore, actively controlling the temperature of the micromirror array—i.e., adjusting it to a target temperature or target temperature range by measurement and heating or cooling—may be beneficial. Thus, a temperature control device for the liquid can be provided. This device may have a sensor unit for measuring the liquid temperature and a temperature control unit for adjusting the liquid temperature to a preset temperature value, i.e., heating or cooling based on the measured value and the preset temperature. In this way, deviations caused by temperature can be avoided or at least reduced.

[0028] Therefore, when ambient light passes through the deflection unit, its refraction is so minimal that changes in ambient light—particularly within the wavelength range and / or at least the angular range and / or at least the temperature range—are below the user's perception threshold. Consequently, material transitions—i.e., the micromirror elements and / or support structures and / or other components surrounded by liquid—are virtually invisible to the user. Thus, micromirror elements can be arranged over a large area in front of the user's field of vision without interfering with their perception of the surrounding environment, and consequently, their perception of the virtual image, significantly enhancing the immersive experience when using the glasses display system.

[0029] In another embodiment, the micromirror elements are mechanically coupled to a common actuator element, particularly through a two-dimensional guide matrix structure. The support structure can mechanically scan the guide matrix structure to achieve independent tilting (i.e., angular positioning) of the micromirror elements. Alternatively, each micromirror element can be designed to be coupled to an independent actuator element. Therefore, in both cases, the angular positioning of the micromirror elements can be controlled according to a preset specification—one form being a mechanical guide, the other being, for example, a lookup table—through either a common actuator element or independent actuator elements. In this case, the common or independent actuator elements can be designed to move at least some of the micromirror elements (particularly most and / or all of them) independently and / or non-linearly. Thus, the angular positioning of the reflecting surface can be set independently and / or non-linearly by the guide matrix structure and / or actuator control commands, etc. This independent and / or non-linear adjustment ensures that the deflected light always reaches the eye and forms a larger coherent virtual image there. Therefore, the shared actuator element reduces the number of components required for the deflection unit within the user's field of vision. This helps reduce the visibility of structures in the user's field of vision, thereby enhancing immersion.

[0030] Each micromirror element can be equipped with an independent angle sensor to measure its corresponding angular positioning. This allows for comparison of the target on each reflective surface with the actual angular positioning, thereby helping to reduce unnecessary offsets of virtual pixels in the virtual image. With the help of such angle sensors, small deviations on the order of 1 / 120° from the set value can be compensated by sending corresponding control signals to the actuator element (or multiple actuator elements) (thus via software).

[0031] In one embodiment, each reflective surface is specified as a hexagonal reflective surface, and in particular, each micromirror element has a coating on its reflective surface. The diameter of the reflective surface, particularly the total height and / or total width, can be at least 1 mm, particularly at least 2 mm, and / or at most 10 mm, particularly at most 4 mm. The hexagonal structure allows the micromirror elements to be arranged in a particularly dense manner, thereby presenting a large area of ​​virtual image at high resolution; this presentation method effectively reduces image artifacts without diminishing immersion due to the reduced visibility of the micromirror elements and related components. If polarized light is used to generate the virtual image, a coating with higher reflectivity is preferred. For example, a reflectivity of 20% can be selected. The reflectivity can be largely independent of wavelength, i.e., its deviation within the relevant (visible light) wavelength range is, for example, less than 10% (i.e., reflectivity between 10% and 30%), preferably less than 5% (i.e., reflectivity between 15% and 25%). Because two polarization states exist simultaneously in ambient light when observing the natural environment through the reflective surface of a partially mirrored surface, the effective transmittance of the micromirror coating is higher. The coating also allows for the definition of desired reflective properties without negatively impacting the visibility of the micromirror element due to other factors, such as its geometry.

[0032] In this case, a coating whose reflective properties match the emission spectrum of the display unit is particularly advantageous, especially matching the peaks in that emission spectrum. Typically, a display unit has multiple spectral peaks (“peaks”), generally corresponding to red, green, and blue. Therefore, for the sub-wavelength ranges distributed around these peaks, a higher reflectance should be selected; while for the remaining wavelength ranges, a lower reflectance should be selected as much as possible, preferably at least substantially zero. The sub-wavelength ranges are distributed around the peaks and separated from each other by intermediate wavelength intervals. The width of the sub-wavelength ranges distributed around the peaks can be 40 nm, particularly 30 nm, preferably 20 nm, and especially preferably 5 nm. The advantage of this is that it allows more of the generally broader spectrum of natural ambient light to enter the eye. Therefore, in practice, this improves transparency without reducing system efficiency. In this case, the peak reflectance can be designed to be up to 100% without significantly reducing the average transmittance; for example, the average transmittance can still be maintained at 90%.

[0033] Therefore, combining the aforementioned high reflectivity with the narrow-band spectral peaks of the primary colors of the display unit (such as red, green, and blue as mentioned above) offers particularly significant advantages. For example, the emission spectrum of the display unit can be designed such that the full width at half maximum (FWHM) of its peaks does not exceed 40 nm, particularly not more than 20 nm, preferably not more than 10 nm, and especially preferably not more than 2 nm. Ideally, the display unit (or the light used by the display unit to generate virtual images) has no more than three peaks. In addition to further improving the transmittance to ambient light, this spectral limitation also has the advantage of significantly simplifying color difference correction, because correction only needs to be performed on a few narrow wavelength ranges such as red, green, and blue, without having to cover the entire wide wavelength range.

[0034] Therefore, when a micromirror element is placed in a medium such as a liquid, light dispersion occurs because the change in refractive index is wavelength-dependent. Light emitted from the display unit strikes the gas-liquid interface at a certain angle, and after reflection by the micromirror element, it is typically deflected to a new angle. The light then strikes the gas-liquid interface again at this new angle and leaves the interface at another, or a third, angle. This is a known characteristic of a dispersion prism, which separates the wavelengths of light. In eyeglass display systems, this separation phenomenon must be corrected. In this case, the smaller the spectral range to be corrected, the better; therefore, the micromirror element should ideally reflect only small spectral peaks or only around small spectral peaks. Thus, through simplified dispersion correction, high system efficiency, high transparency, and high image quality can be achieved.

[0035] In another embodiment, the dimensions (i.e., width and / or height) of the reflective surfaces are at least partially different. Specifically, when the user's eyes are in a forward-facing neutral position, one or more reflective surfaces closer to the user's central axis can be smaller than one or more reflective surfaces farther from the user's central axis. For the virtual image to be visible to the naked eye, light emitted from the display unit's output aperture ("emission aperture") must be deflected into the pupil of the eye by corresponding micromirror elements. This derives the relationship between the maximum size of each micromirror element and the diameter of the display unit's emission aperture. In a preferred embodiment, the dimensions of each reflective surface are chosen to be as close as possible to or equal to the maximum size. The maximum size is smaller near the central axis and larger further away. This design leverages the reduced number of mirror transition points—at which each virtual sub-image observable only by a single micromirror element must be contiguous with an adjacent sub-image. To avoid artifacts, this sub-image must be calculated for each transition point. Therefore, reducing the number of micromirror elements reduces this computational burden. Furthermore, when the light beam only partially illuminates the micromirrors, the diffraction effect at the edges of each micromirror element is minimized. Therefore, a design using fewer micromirror elements can minimize such diffraction artifacts, resulting in higher-quality virtual image display and enhanced immersion.

[0036] In another embodiment, the reflecting surface is specified as a concave reflecting surface. Alternatively or supplementary, the reflecting surface can also be a planar reflecting surface. Concave reflecting surfaces achieve extremely high light efficiency. This allows the light from a single physical pixel of the display unit to be projected onto a corresponding micromirror, which then deflects the light to a predetermined position in the user's eye regarding the virtual image. Therefore, multiplexing is unnecessary in this case. The concave reflecting surface can also be designed to focus directly onto the display unit. In this case, other optical elements are no longer necessary, but all micromirror elements simultaneously constitute the display unit. Therefore, multiplexing technology must be employed to uniquely map pixel information (the light emitted by the physical pixels in the display unit) to a single viewing direction.

[0037] Planar reflective surfaces are particularly suitable when an additional focusing unit is incorporated into the optical path between the display unit and the deflection unit (e.g., to address visual convergence and / or compensate for user visual impairments). This additional focusing unit allows the focus of the virtual image to be consistently adjusted to the current gaze direction. For this purpose, information regarding eye positioning (“eye tracking”, as described below) can be utilized. Preferably, the focal length of the entire virtual image is uniformly adjusted, for example, by using an electrically controllable liquid lens (“liquid lens”). Other feasible optical solutions include stacking multiple transparent displays together. By using planar reflective surfaces, arbitrary focal lengths of the display unit can be achieved without introducing imaging errors—while other known beam splitter techniques (e.g., so-called “waveguides”) must be designed for specific focal lengths.

[0038] By using additional focusing units, especially liquid lenses, users' visual impairments can be dynamically (i.e., personalized for different users) compensated, even if not for addressing visual convergence and accommodation issues. In this case, an additional lens element must be added between the ambient light and the deflection unit in the optical path from the visual field to the eye. For example, users could consider wearing regular glasses for vision correction over their augmented reality glasses, or using appropriate eyeglass frames. Adding more lens elements between the display unit and the deflection unit can further optimize the vision correction effect.

[0039] In one embodiment, the support structure and / or micromirror element and / or other components surrounded by liquid are designed in a shape such that ambient light, at least for the majority of the user's field of vision, for example from predetermined sub-regions within the field of vision, passes through the interface between the transparent material and the liquid and / or the liquid and the transparent material at a small angle, particularly at least primarily at an angle of less than 45°. Therefore, ambient light should illuminate the aforementioned interface at a very gentle angle in as few areas as possible (ideally none), and at a steep angle in as many areas as possible (ideally all areas). Since ambient light from different regions of the field of vision will illuminate the aforementioned interface at different angles, particularly important portions can be selected for a given sub-region, such as the area around the central axis in the user's field of vision. Therefore, for the support structure and / or micromirror element and / or other components, a geometry is chosen to minimize perceptible refraction and diffraction effects, thereby further reducing the visibility of the aforementioned components and the aforementioned effects.

[0040] In another embodiment, the reflecting surfaces of at least some of the micromirror elements (particularly most of the micromirror elements) overlap in orthogonal projection onto a plane perpendicular to the user's central viewing axis. This applies when the micromirror elements or reflecting surfaces are arranged in parallel (and should remain parallel as much as possible if physical contact occurs). By employing overlapping micromirror elements, diffraction effects can be reduced and resolution improved. Preferably, the micromirror elements overlap only in areas with sufficiently large tilt angles (e.g., within an effective angular positioning range defined by one or more actuator elements) so that physical contact does not occur during operation for the intended purpose. Therefore, it can be specifically stipulated that, during normal use, the reflecting surfaces must not overlap in an area perpendicular to the central viewing axis at least at some point.

[0041] It can be designed so that the reflective surfaces of the micromirror elements near the user's central visual axis overlap in orthographic projection. This design is advantageous because the display unit is typically mounted on the side of the temple of the glasses, and when the line of sight is forward, the tilt angle of the visible micromirrors is large enough to mechanically achieve overlap. On the side closer to the temple, there is an area where overlap is not possible. Therefore, within the forward line of sight, higher resolution can be achieved due to overlap and the resulting reduction in diffraction, which is beneficial for the application of augmented reality glasses. Furthermore, when people look to the side, they typically turn their heads and focus in conjunction with the central central axis ("forward line of sight"), rather than by rotating their eyeballs; therefore, it is precisely in the central central axis (i.e., the "forward line of sight") region that the sense of immersion is enhanced.

[0042] In one embodiment, the micromirror elements are arranged on a one-dimensional or two-dimensional curved surface. Here, the curved surface can be defined as a two-dimensional manifold in three-dimensional space. Therefore, the micromirror elements are arranged at least partially offset from each other along the central viewing axis. This is particularly advantageous when combined with the overlapping micromirror elements described above, because this allows for overlap in more areas—i.e., for more micromirror elements (thus achieving the aforementioned advantages).

[0043] In another embodiment, the housing element has an anti-reflective coating on the side facing the display unit, and the anti-reflective properties of this coating vary in localized areas. Since light emitted from the display unit typically couples from the temple side to the deflecting unit and is then reflected by the micromirror elements, light also reflects at the interface between the air and the transparent material of the housing element. This reflection is perceptible to the naked eye at different locations depending on the pupil position and is an undesirable phenomenon, but it can be effectively suppressed by the anti-reflective coating. This also reduces image artifacts, thereby enhancing immersion.

[0044] In a preferred embodiment, the display unit can emit polarized light, particularly linearly polarized light, thereby further reducing unwanted reflections through a matching anti-reflective coating. Furthermore, it is also beneficial to adjust the polarization direction accordingly to minimize reflection. If the direction of light emission (relative to the side of the housing element facing the display unit) is selected as close as possible to the Brewster angle, based on the overall geometry of the eyeglass display system, unwanted reflections can be almost completely avoided. In the coating process of ordinary eyeglass lenses, an anti-reflective coating is typically applied to ensure a clear field of vision when observing natural environments. Therefore, for eyeglass display systems, it is highly advantageous to select a coating that maintains low reflection during normal vision while effectively reducing the reflection of light emitted by the display unit. Since the light emitted by the display unit can only be seen over a very small area, locally variable coatings are advantageous: such coatings can eliminate reflections of light emitted by the display unit within a virtually enhanced field of vision and significantly improve vision in other areas.

[0045] In one embodiment, the glasses display system includes an eye-tracking device for detecting the user's eye direction, and a control unit for controlling the deflection unit based on the eye direction detection results. This allows light to be directed to the pupil of the eye, thereby improving light efficiency and avoiding undesirable effects such as "bright eyes"—where others can see reflections of deflected light in the user's eyes. The improved energy efficiency also allows for reductions in battery weight and the required size of the display unit, further enhancing the immersive experience.

[0046] In this scenario, the control unit can be designed to control the display unit according to mapping rules stored within it. These rules specify that, based on the eye's orientation, corresponding virtual pixels in the virtual image are mapped to corresponding physical pixels in the display unit. Therefore, for different eye orientations (i.e., at different times), the content of the virtual pixels is determined by different physical pixels. This is because when the micromirror elements shift, the mapping relationship between physical pixels in the display unit and virtual pixels in the virtual image changes, and this change occurs differently for each pixel combination. This non-linear change is compensated for by the mapping rules, ensuring that the virtual pixels in the virtual image maintain their intended positions. This improves image quality and allows for the presentation of particularly large virtual images.

[0047] In one embodiment, an adjustable aperture unit, which can be configured via a control signal, may be provided in the optical path between the display unit and the tiltable micromirror element, or within the display unit. This adjustable aperture unit is designed to adjust at least one beam position and / or at least one beam width corresponding to the beam position of light deflected by the reflective surface of the tiltable micromirror element, according to the control signal. The adjustable aperture unit allows for the determination of the incident position of light on the deflection unit or other optical elements (e.g., microlens devices on the display unit) using the adjustable beam position, thereby determining the micromirror element illuminated by the light. Simultaneously, the adjustable beam width allows for the determination of the size of the light incident area on the deflection unit, thereby excluding certain micromirror elements near the beam position from the illumination range, for example, only a small portion of the micromirror elements will be illuminated when the beam width is large (as will be explained in more detail below).

[0048] The effect is that, with the help of control signals and an adjustable aperture unit (also known as an adaptive aperture), the output aperture ("emission aperture") of the display unit can be dynamically adjusted—that is, by changing the control signals over time. Therefore, even using a display unit consisting of a light-emitting display screen and a microlens device ("microlens array") located behind it, as described above, multiplexing can be achieved, thereby gaining the corresponding advantage of improved spatial resolution. This combines the advantages of different technical solutions.

[0049] Generally speaking (i.e., without considering the aperture unit), the light emitted from the display unit forms a mirror image through each micromirror element, which is then seen by the human eye. Designing the light emitted from the aperture to be very large could increase the complexity of possible multiplexing processing and also increase the weight of the augmented reality glasses without providing any additional value. Therefore, the diameter of the light emitted from the aperture should be designed to be as small as possible. If the light emitted from the display unit is too small, it cannot project virtual images in every direction of the user's gaze, thus limiting the virtual augmented field of view.

[0050] Therefore, the exit aperture of the display unit needs to reach a certain minimum size to ensure that the light path can travel from the display unit to the micromirrors and then from the micromirrors to the human eye in all augmented reality viewing angles—that is, within the largest possible field of view capable of virtual augmentation. Thus, pixel image information is projected as a beam of light with a diameter equal to the exit aperture of the display unit onto the micromirrors (i.e., the entire "micromirror array") on the deflection unit. For example, the typical diameter of the exit aperture is 8 mm. The typical diameter of the micromirrors and their reflective surfaces is 2-4 mm. Therefore, the beam of light for one pixel image information will simultaneously illuminate multiple adjacent micromirrors. Since each micromirror is ideally adjusted according to the current orientation of the eye so that the central beam of light emanating from the pupil is projected onto the center of the exit aperture of the display unit, when the light of pixel image information simultaneously illuminates two adjacent micromirrors, the light may also be perceived by the eye simultaneously. However, because the adjacent micromirrors are oriented differently, the same pixel image information will be perceived in two different reflection directions, thus producing one or more virtual ghostings.

[0051] By using an adjustable aperture unit, for each pixel image information, only one cropped beam of light is projected onto different micromirror elements or different microlenses in the microlens device, thereby minimizing the amount of light that may hit the (most) adjacent micromirror elements or microlenses, or allowing only light that will not hit the pupil and is therefore invisible to these micromirror elements or microlenses.

[0052] Therefore, it is advantageous to design the adjustable aperture unit such that, for each micromirror element, the viewing direction of the corresponding virtual image is set only when the area occupied by light incident on that micromirror element is greater than the area occupied by light incident on other (most) adjacent micromirror elements. For extreme viewing directions that primarily (i.e., at least to a large extent) illuminate adjacent micromirror elements and (at a certain moment) only illuminate the micromirror element being observed at a very small proportion (e.g., barely glancing over it), they should correspondingly not enter the exit aperture of the display unit. Thus, for example, in a time-division multiplexing framework, a smaller exit aperture of the display unit can be selected for micromirror elements observed at a specific multiplexing time to improve image quality. This can be achieved through the adjustable aperture unit and / or microlens device.

[0053] The advantage of this approach is that it minimizes diffraction during imaging, thereby achieving optimal sharpness in the virtual image. This is because the micromirror element deflects only a small portion of the total beam initially emitted by the display unit into the eye, effectively acting as an aperture. In other words, the beam can be truncated when only a portion is reflected. In optics, it is well known that diffraction is exacerbated when the aperture is small. Therefore, it is advantageous to position the beam onto the micromirror element using an adjustable aperture unit, ensuring that it is not truncated or is minimally truncated by the micromirror element.

[0054] In another embodiment, the adjustable aperture unit is designed to adjust the beam position by adjusting the position of at least one transparent sub-aperture region (i.e., a sub-aperture region switched to a transparent state by a control signal), which is located within the overall aperture region that can be switched to a transparent or opaque state by a control signal. Within the entire aperture range, the remaining regions complementary to at least one sub-aperture are opaque, i.e., switched to an opaque state by a control signal. Therefore, one or more sub-aperture regions can be set to a transparent state such that only these sub-aperture regions can transmit light from one or more pixel image information associated with the respective sub-aperture region, while other pixel image information cannot reach the deflection unit. As described below, the position of the transparent sub-region may change over time, for example, to achieve time-division multiplexing. The advantage of this is that it avoids or at least reduces crosstalk between pixel image information—crosstalk that causes the aforementioned ghosting phenomenon. Therefore, even with a large field of view, image quality is improved, thereby enhancing the immersive experience of the system.

[0055] The features and combinations thereof (including those in the general introduction), as well as those disclosed in the accompanying drawings or only in the drawings, may be used individually, in combination, or in conjunction with other features, or with the omission of some disclosed features, without departing from the scope of the invention. Therefore, embodiments not explicitly shown and described in the drawings, but formed by individually combining the features disclosed in the drawings, are also part of the invention. Therefore, even if certain embodiments and combinations of features do not include all features in the initially drafted independent claims, they should be considered disclosed. Furthermore, embodiments and combinations of features that differ from the feature combinations or exceed the scope described in the dependent claims should also be considered disclosed.

[0056] In the context of this patent, "lateral / longitudinal" can be understood as "at least substantially perpendicular / parallel," that is, "perpendicular / parallel" or "substantially perpendicular / parallel," meaning perpendicular / parallel except for a certain predetermined deviation. For example, the predetermined deviation is at most 15°, preferably at most 5°, and particularly preferably at most 3°. Correspondingly, in the context of this patent, "opposite direction" can be understood as "at least substantially opposite direction," that is, "at least substantially antiparallel." The limitation of "substantially" can also refer to the maximum permissible deviation specified as a percentage, such as at most 15%, preferably at most 5%, and particularly preferably at most 3%. Detailed Implementation

[0057] The exemplary embodiments will be described in detail below with reference to the schematic diagrams.

[0058] Figure 1 shows a plan view of an exemplary embodiment of the eyeglass display system;

[0059] Figure 2 A plan view of an exemplary embodiment of a glasses display system is shown, which includes misaligned and overlapping micromirror units;

[0060] Figure 3 shows a schematic diagram of optimizing the geometry of the micromirror unit to reduce its visibility;

[0061] Figure 4 A plan view of an exemplary embodiment of a glasses display system is shown, which is equipped with an additional focusing unit and vision correction function;

[0062] Figure 5 Examples of wavelength functions of the refractive index of liquids and transparent materials are shown;

[0063] Figure 6 shows the Fresnel reflectivity as a function of the incident angle, taking a specific wavelength as an example.

[0064] Figure 7 The refraction effect, as a function of incident angle and wavelength, is shown;

[0065] Figure 8 A plan view of an exemplary embodiment of a glasses display system is shown, which has a concave reflective surface;

[0066] Figure 9 A plan view of another exemplary embodiment of the eyeglass display system is shown, which has a concave reflective surface; and

[0067] Figure 10 shows a schematic diagram of controlling the deflection of micromirror units using a guiding matrix structure; and

[0068] Figure 11 shows a front view and an interior view of another exemplary embodiment of the eyeglass display system.

[0069] In the accompanying drawings, features that are identical or have the same function are labeled with the same reference numerals.

[0070] Figure 1 shows a plan view of an exemplary embodiment of the eyeglass display system, illustrating only half of the system, i.e., the case of a single eye. For a binocular system, a symmetrical extension can be made accordingly.

[0071] Figure 1a Half of the eyeglass display system 1 is shown, for example, the left half when viewed from above, or the right half when viewed from below. Light rays 163", 161", and 162" are emitted by the display unit 14 (located to the side here), and are imaged by the optical system 13 such that the light rays 163", 161", and 162" are reflected by micromirror elements, such as 12, 12', and 12" (partially), of the deflection unit 17 and projected onto the pupil 11 of the eye 10. The optical system 13 may include one or more lenses and / or mirrors and / or other optical elements, such as one or more aperture units (including adaptive, adjustable via control signals). The optical assembly 13 may also include a microlens device consisting of multiple microlens elements, and / or a projection optics system as described in the general description.

[0072] The eye here faces the central line of sight direction B (parallel to the y-direction). If the micromirror elements 12, 12', 12" (e.g., a typical size of about 2 mm) are at least substantially transparent to ambient light, the natural environment 100 can be observed along the light rays 161', 162', 163', and a virtual image composed of the light rays 161" 162" 163" can be superimposed on the ambient light rays 161', 162', 163'. The optical system 13 can be designed to make the virtual image clearly visible at finite or infinite distances. The micromirror elements 12, 12', 12" are mounted with a movable tilt, so their angular positioning can be adjusted in two-dimensional space.

[0073] In this invention, micromirror elements 12, 12', 12" and a support structure 200 (Fig. 10) for supporting the micromirror elements 12, 12', 12" (not shown in the figures for clarity) are arranged within a sealed housing element 17a filled with liquid 23. Here, the liquid 23 is chosen to make the refractive index of the micromirror element material as similar as possible to that of the liquid. It is well known that when a glass component is immersed in a liquid with a refractive index nearly identical to its own, it becomes invisible. Two effects occur in this process. First, Fresnel reflection, which occurs when light transitions from one medium to another with a different refractive index, disappears. On the other hand, light does not refract at the material transition. However, even with very small differences, partial reflection and total internal reflection can still occur when the incident angle is very gentle when the light strikes the interface. Figure 6 shows and explains this in more detail.

[0074] In this invention, by cooperating with the eye-tracking device 15, while determining the orientation of the eye 10 (and thus the position of the pupil 11), the light rays 163", 161", and 162" emitted by the optical system 13 can be guided very precisely into the pupil 11 of the eye 10. When the eye moves—for example, as Figure 1b As shown in the lateral eye movement diagram, the position of the pupil 11 changes, and the micromirror elements 12, 12', and 12" adjust their orientation accordingly so that the light beams 163", 161", and 162" emitted by the optical system 13 are again precisely projected onto the pupil 11. In addition to the support structure for the micromirror elements 12, 12', and 12" they are also equipped with one or more actuator elements (not shown here for clarity) for adjusting the angle positioning, thereby adjusting the corresponding reflection angle; furthermore, an independent angle sensor (also not shown here) is provided to measure the current angle positioning.

[0075] This allows for the establishment of a control loop to adjust the micromirror elements 12, 12', and 12" so that the light rays 163", 161", and 162" emitted by the optical system 13 can be projected onto the pupil 11 of the eye 10. To this end, the position of the pupil 11 is measured by the eye-tracking device 15, and the control unit calculates the set angle positioning of the micromirror elements 12, 12', and 12" and then compares it with the actual position of the micromirror elements 12, 12', and 12" . Subsequently, the actuator element adjusts the deviation between the actual value and the set value, while striving for a sufficiently high speed so that the eye 10 can stably perceive the virtual image even when moving. Given that the maximum speed of the eye can reach 1000%, its minimum processing speed can be calculated.

[0076] When the angular positioning of the micromirror elements 12, 12', and 12" changes, the line of sight changes with the new orientation of the eye 10, thus deviating from the central line of sight B. Figure 1a and Figure 1b It can be observed that, Figure 1a Light 161" in the middle is reflected as light 161, while... Figure 1b The light is reflected as light 161b, and the propagation direction of light 161b is different from that of light 161. This causes a change in the mapping relationship between each virtual pixel in the virtual image and the corresponding physical pixel in the display unit 14. Therefore, the image information emitted from the display unit 14 along direction 161" must be adjusted according to the change in angular positioning.

[0077] Therefore, when the eye moves, not only should the orientation of the micromirror elements 12, 12', and 12" be adjusted, but also the pixel light image information generated on the display unit 14 should be adjusted. However, since the geometric layout between the projector and the micromirrors is known, the new image information to be displayed can be calculated using optical laws, so that the observer perceives no displacement of the virtual image at the predetermined position of the pupil (the preset "eye zone"). The corresponding mapping rules can be stored in the control unit of the display unit 14.

[0078] At this point, the control of the micromirror elements 12, 12', 12" is preferably performed in such a manner that the central beam of light—that is, the beam of light originating from the center of the pupil and striking the center of the corresponding micromirror element—is deflected to the center of the optical system 13, for example, along the direction of light ray 163b in Figure 1b. As previously mentioned, changes in the tilt of the micromirror elements 12, 12', 12" alter the viewing angle of the display unit 14 when observing pixel image information. Therefore, it is advantageous not to continuously adjust the micromirror elements 12, 12', 12" but rather to adjust them in steps based on a threshold, which defines the permissible degree of deflection from the center when light ray 163b strikes the pupil 11 of the eye 10. This is beneficial because the eye undergoes minute movements, thus eliminating the need for compensation. Furthermore, it is also advantageous for the micromirror elements 12, 12', 12" to be embedded in a liquid 23, which has a damping effect and can suppress vibrations (i.e., small and rapid angular movements).

[0079] In Figure 1, micromirror elements 12, 12', and 12" are drawn on the same plane. Figure 2As shown, these structures can also be arranged on a one-dimensional or two-dimensional curved surface. Accordingly, the micromirror elements 12, 12', 12" are staggered relative to each other along a central line of sight perpendicular to the main extension plane (here, the xz plane) of the deflection unit 17; for example, two, more, or all adjacent micromirror elements 12, 12', 12" are staggered relative to each other. The advantage of this is that spectacle lenses typically have a curved surface—the so-called base curvature—so the design of the spectacle display system 1 can more closely resemble conventional eyeglasses. Furthermore, more micromirror elements 12, 12', 12" can be designed to overlap each other, and / or the degree of overlap between adjacent micromirror elements 12, 12', 12" can be increased.

[0080] Figure 3a Different geometries of the micromirror elements and their effects on unintended refraction and reflection are shown. Since the refractive index of liquid 23 is almost the same as that of the material of micromirror elements 12 and 12', the Fresnel reflection phenomenon that usually occurs when transitioning from one medium to another with a different refractive index does not exist, and the light rays 21, 21', 22, and 22' will not be refracted.

[0081] However, even with very small differences, partial reflection and total internal reflection can still occur when light strikes the corresponding interface at a very parallel angle. For example, beam 22" is shown as such a partially reflected beam. Accordingly, Figure 3a The diagram shows two micromirror elements 12 and 12' with different geometries. The two micromirror elements 12 and 12' form a translucent reflective surface 25, for example by coating the micromirror elements 12 and 12' with a thin metallic coating. The micromirror elements 12 and 12' themselves are made of, for example, plastic or glass, and their first refractive index should be matched as closely as possible to the second refractive index of the surrounding liquid 23.

[0082] Figure 3a The difference between the two exemplary micromirror elements 12 and 12' lies in their geometry. The interface formed by micromirror element 12' allows the visual beam of the eye 10 corresponding to beam 22 to enter the optical interface at a relatively small angle. In this case, depending on the actual angle, total internal reflection or partial reflection may occur. These reflections reduce the transparency of deflection unit 17 because partial reflection produces ghosting. Therefore, it is advantageous that the mechanical structure of the micromirror element be designed so that the visual beam passes through the interface of the refractive index transition as perpendicularly as possible. Thus, the geometry of micromirror element 12 with rounded back corners is superior to that of micromirror element 12' with a rectangular geometry.

[0083] Figure 3bCorrespondingly, another geometry of the micromirror element 12" is shown. In this cross-section, the micromirror element 12" has a trapezoidal geometry, where the long side of the trapezoid corresponds to the reflecting surface 25. The light beam 23 passing through the two parallel bases of the trapezoid remains parallel in front of and behind the micromirror element 12" and in front of and behind the deflection unit. However, the light beam 23' passing only through the long base and one of the side edges of the trapezoid is not parallel, because the angle of incidence is too small when the beam passes through the interface on the side edge. Therefore, the trapezoidal geometry of the micromirror element 12" is superior to the rectangular geometry of the micromirror element 12', but inferior to the geometry of the micromirror element 12 with rounded corners on the back.

[0084] Figure 4 A plan view of an exemplary embodiment of a glasses display system is shown, which is equipped with an additional focusing unit and has vision correction functionality. Here, the focal length of the additional focusing unit 13", which is part of the adaptive optics system, is adjusted by the control unit 110. For example, the focus of the virtual image can be selected to be set at infinity (light path / beam 112) or at a finite point (light path / beam 111). This solves the problem of visual convergence accommodation. If the focusing speed can be set faster than the refresh rate, different focal planes can even be set within the same virtual image.

[0085] By adding an additional lens element 13'" between the deflection unit 17 and the environment 100, vision correction functionality can be integrated here with minimal engineering effort. The control unit 110 should be designed accordingly.

[0086] Figure 5 Examples of refractive indices (“refractive index”) for liquids (here, oil) and transparent materials (here, quartz glass) are shown, measured at example temperatures as a function of wavelengths (“wavelength in nm”) from 400 nm to 700 nm. Curve 80 corresponds to the first refractive index of liquid 23, and curve 81 corresponds to the second refractive index of the materials of micromirror elements 12, 12', and 12" respectively. It should be noted that in this case, the maximum difference between the first and second refractive indices occurs at 400 nm, and this difference does not exceed the relatively small value of 0.004. It is particularly advantageous if the two curves 80 and 81 intersect within the green wavelength range (520 nm–565 nm), as studies have shown that the human eye has a higher resolution for artifacts in the green wavelength range compared to the red and blue wavelength ranges. The numerical values ​​of Fresnel reflection and refraction effects for these refractive indices are shown in Figure 6 and... Figure 7As shown, this makes the material transition virtually invisible, thus also making the micromirror elements 12, 12', 12" and the supporting structure or housing element 17a virtually invisible. It should also be noted that reflections can also occur on the inner side 17b (Fig. 1) of the housing element 17a facing the user and display unit 14, as a boundary layer. This can cause interference because the inner side 17b is misaligned in the y-direction relative to the micromirror elements 12, 12', 12" . These bothersome reflections can be reduced or eliminated by employing an anti-reflective coating similar to that commonly found in conventional eyeglasses.

[0087] Figure 6a In the diagram, curve 82 represents the wavelength at 450 nm. Figure 4 The Fresnel reflectance of the two refractive index combinations shown is expressed as a percentage of total intensity, with the horizontal axis representing the angle of incidence (in degrees). The refractive index difference here is approximately 0.002. Clearly, due to this effect, the proportion of reflected light intensity increases exponentially. In this case, when the angle of incidence is less than 80°, the reflectance is close to zero; as the angle of incidence approaches 90°, i.e., when the light is incident in a straight, almost parallel manner to the boundary layer, the reflectance rapidly rises to 100% within a few degrees (the angle of incidence is measured relative to a vertical line perpendicular to the interface).

[0088] from Figure 6b It can be seen that when the incident angle is less than about 70°, the proportion of reflected light is less than 0.01%, so Fresnel reflection can be ignored within this incident angle range. Figure 6b It shows Figure 4 The figures show the Fresnel reflectance (reflection in % (100% max)) of the two refractive indices at a wavelength of 450 nm, ranging from 0° to 70°, as a function of the angle of incidence in degrees. Curve 82a shows the trend for s-polarized light, and curve 82b shows the trend for p-polarized light.

[0089] In addition to Fresnel reflection as shown in Figure 6, refraction effects must also be considered, which also depend on the angle of incidence and wavelength. Accordingly, Figure 7 This demonstrates the refractive effect as a function of wavelength, specifically the change in indirection in degree as a function of the angle of incidence in degree and wavelengths from 400 nm to 700 nm. Temperature and refractive index are also shown here. Figure 4 and Figure 5The temperature and refractive index are consistent. Solid curves 83a, 83i, and 83z describe the deflection of light from a medium with higher optical density to a medium with lower optical density, in the wavelength range from 400 nm (curve 83a) to 700 nm (curve 83z). Dashed curves 84a, 84i, and 84z describe the deflection of light from a medium with lower optical density to a medium with higher optical density, in the wavelength range from 400 nm (curve 84a) to 700 nm (curve 84z).

[0090] Since the angular resolution of the human eye is limited to approximately 1 / 60° = 0.0167, refraction within the core region W around 0 degrees is imperceptible to the user and therefore does not pose a problem. Thus, as can be seen from curves 83i and 84i, when the wavelength exceeds 550nm, light with an incident angle within approximately 38° is imperceptible to the user and therefore does not pose a problem. Therefore, based on the overall geometry of the glasses display system 1, the optimized geometry of the micromirror elements 12, 12', and 12" can be derived from these schematic diagrams.

[0091] Figure 8 A plan view of an exemplary embodiment of a glasses display system with a concave reflective surface is shown. Using the illustrated principle, a multiplexing method can be circumvented.

[0092] This method offers exceptionally high light efficiency because the entire light ray 163", 161", and 162" is guided into the pupil 10 of the eye 11. For this purpose, the optical system 13' is designed to image the light emitted from the display unit 14 onto an intermediate image 101. However, the intermediate image 101 need not be perfectly sharp. For example, it may be beneficial to compensate for aberrations caused by subsequent reflections at the curved micromirror elements 12, 12', and 12" at this stage. Here, the selection of the intermediate image 101 should ensure that it can be imaged onto the pupil 11 of the eye 10 through the curved micromirror elements 12, 12', and 12". Based on the geometric arrangement between the pupil position and the micromirror elements 12, 12', and 12" and the diameters of the pupil 11 and the micromirror elements 12, 12', and 12" respectively, the field of view 102 or 103 corresponding to each micromirror element 12 or 12' can be determined.

[0093] At this point, the intermediate image 101 is positioned at a location where the adjacent field of view 102 and 103 do not overlap. Therefore, the rays 163", 161", and 162" of the physical pixels of the display unit 14 are only projected onto the micromirror elements 12, 12', and 12", without the need for other multiplexing methods.

[0094] exist Figure 8In the illustrated embodiment, each beam 104, 105 has its own central focal point 106, 107, which is mapped to a physical pixel on the display unit 14. Since such beams 105 illuminate not only one micromirror element 12 but also another micromirror element 12', which in turn projects light onto another independent physical pixel on the display unit 14, redundant physical pixels are required; that is, the number of physical pixels must be greater than the number of virtual pixels displayed in the virtual image.

[0095] In one embodiment, the intermediate image 101 can also be designed such that adjacent visual fields 102, 103 overlap. The design of the corresponding micromirror elements 12, 12' should ensure that the same intermediate focus 107 is used for the same viewing angle illuminating the pupil 11, thus requiring only one physical pixel for each line of sight. This design is optically more demanding because the micromirror elements 12, 12', 12" not only need to achieve sharp imaging but also must control distortion to ensure that adjacent micromirror elements 12, 12', 12" with different tilt angles can collectively form the intermediate image 101. When designing the optical system 13', the characteristic that maximum sharpness is achieved only in the central region (i.e., the so-called "fovea region"), that is, when the eye 10 is directly aligned with the corresponding micromirror element 12, 12', 12'" can be utilized. When the eye 10 deviates, the person's imaging ability decreases rapidly and significantly, so aberrations are usually not noticeable in this case.

[0096] Figure 9 A plan view of another exemplary embodiment of a spectacle display system with a concave reflective surface is shown, which is consistent with... Figure 8 The system shown is similar, but optical element 13' is optionally omitted.

[0097] Here, the micromirror elements 12, 12', and 12" are designed to directly focus light onto the display unit 14. Furthermore, other optical elements 13'" can be added to improve image quality. Therefore, all micromirror elements 12, 12', and 12" simultaneously image the display unit 14. Thus, to uniquely map pixel information to a single viewing direction, a multiplexing method must be employed. For this purpose, a multiplexing method based on a switchable, adjustable aperture unit can be used, whereby at a certain moment, unnecessary micromirror elements 12, 12', and 12" are blocked, while the aperture unit remains transparent only to the required micromirror elements. This switchable, adjustable aperture unit can be implemented using a liquid crystal shutter or similar method.

[0098] Therefore, in different implementations, the focal points of the micromirror elements 12, 12', 12" can be located at different distances. Figure 8An example is shown where the focus 101 is located in front of the display unit 14. Figure 9 In this case, the focus is on the display screen. The focus can also be located at infinity behind the display unit 14. Therefore, the focal plane can be freely set in front of, above, or behind the display unit 14. If a pixel's information is simultaneously projected onto multiple micromirror elements 12, 12', 12", a multiplexing method (such as the method described above) is required to uniquely present the pixel information in the image direction.

[0099] Figure 10 shows a schematic diagram of controlling the deflection of micromirror units using a guiding matrix structure.

[0100] Figure 10a The micromirror unit 12 is schematically shown, which is tiltably arranged on the support structure 200 via two tilting axes K1 and K2. Here, in the common actuator element 201 ( Figure 10b A two-dimensional guide matrix structure 202 is formed on the actuator element 201, which has corresponding guide surfaces 203a, 203a', 203b, 203c, and 203d. Here, each micromirror unit 12, 12', and 12" scans the guide matrix structure 202 in the form of the corresponding guide surfaces 203a, 203a', 203b, 203c, and 203d through its respective sensors 204a, 204a', 204b, 204c, and 204d – each tilting axis K1 and K2 is equipped with a sensor. Therefore, when the actuator element 201 is displaced, the corresponding micromirror units 12, 12', and 12" can tilt nonlinearly in different ways according to the spatial shape of the guide surfaces 203a, 203a', 203b, 203c, and 203d, based on the displacement of the actuator element 201.

[0101] Figure 10b This is illustrated by a cross-sectional view along a tilted dimension. For example, when actuator element 201 moves in the negative x-axis direction, the two micromirror units 12, 12" tilt counterclockwise, while the other micromirror unit 12' tilts clockwise.

[0102] Figure 11 illustrates another exemplary embodiment of the glasses display system. For example... Figure 11a As shown, the glasses display system 1 in this example is equipped with a deflection unit 17, which contains multiple micromirror units 12, 12', and 12" that are arranged in a large-area distribution within the field of view, which is comparable to that of conventional glasses. Furthermore, Figure 11bThe internal structure of the deflection unit 17 is shown, which contains multiple micromirror units 12, 12', and 12" . For example, partially overlapping micromirror units 12 and 12' are shown here. In the example shown, the micromirror units 12, 12', and 12" are staggered along the y-direction and have different sizes. Here, the reflecting surface of micromirror unit 12" is larger than that of micromirror unit 12', and the reflecting surface of micromirror unit 12' is larger than that of micromirror unit 12.

Claims

1. A glasses display system (1) for displaying virtual images within a user's field of vision, comprising: - Display unit (14) for emitting light rays (163", 161", 162") as computer-generated image information along the emission direction; - A deflection unit (17) for deflecting the light rays (163", 161", 162") emitted by the display unit (14) as computer-generated image information to the user's eye (10), including a plurality of tiltable micromirror elements (12, 12', 12"), the micromirror elements being respectively installed in the support structure (200), each of the micromirror elements having at least one reflective surface (25) for deflecting the light rays (163", 161", 162") emitted by the display unit (14) as computer-generated image information; Its features are: The micromirror elements (12, 12', 12") and the support structure (200) are arranged within the liquid-filled (23) sealed housing element (17a) of the deflection unit (17).

2. The eyeglass display system (1) according to the preceding claim. Its features are: - The micromirror elements (12, 12', 12") and / or the support structure (200) are each at least substantially transparent to ambient light from within the user's field of view, particularly invisible to the user within at least one wavelength range and / or at least one angular range of ambient light, and are made of or contain a corresponding transparent material having a first refractive index; and The liquid (23) used for ambient light is also at least substantially transparent and has a second refractive index that matches the first refractive index (to minimize the deviation), the second refractive index being equal to the first refractive index in particular for at least one wavelength in the green wavelength range.

3. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The micromirror elements (12, 12', 12") are mechanically coupled to a common actuator element (201), particularly through a two-dimensional guide matrix structure (202).

4. The eyeglass display system (1) according to the preceding claim. Its features are: The actuator element (201) is designed such that at least some of the micromirror elements (12, 12', 12"), and in particular most of the micromirror elements (12, 12', 12"), can move differently from each other and / or nonlinearly.

5. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The corresponding micromirror elements (12, 12', 12") have a coating on their reflective surface (25), the coating having reflective properties It matches the emission spectrum of the display unit, particularly the peak values ​​in the emission spectrum.

6. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The reflective surfaces (25) have at least some different sizes, and in particular, one or more of the reflective surfaces (25) closer to the central axis (B) of the user are smaller than one or more of the reflective surfaces (25) farther from the central axis (B) of the user.

7. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The display unit (14) includes a microlens device comprising a plurality of microlens elements, each of the microlens elements corresponding to exactly one of the microlens elements (12, 12', 12").

8. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The shape design of the support structure (200) and / or the micromirror elements (12, 12', 12") is such that ambient light from within the user's field of vision passes through the interface between the transparent material and the liquid (23) and / or the interface between the liquid (23) and the transparent material at least primarily at a small angle, particularly at least primarily at an angle of less than 45°.

9. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The reflective surfaces (25) of at least some of the micromirror elements (12, 12', 12") overlap when orthogonally projected onto a plane spanning the central axis (B) of the user.

10. The eyeglass display system (1) according to the preceding claim. Its features are: In orthographic projection, the reflective surfaces (25) of the micromirror elements (12, 12', 12") overlap each other around the user-centric visual axis (B).

11. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The micromirror elements (12, 12', 12") are arranged on a one-dimensional or two-dimensional curved surface.

12. The eyeglass display system (1) according to any one of the preceding claims. Its features are: The housing element (17a) has an anti-reflective coating on its side (17b) facing the display unit (14), particularly an anti-reflective coating whose anti-reflective properties change in local areas and / or an anti-reflective coating that matches the polarized light of the display unit.

13. The eyeglass display system (1) according to any one of the preceding claims. Its features are: - An eye-tracking device (15) for detecting the orientation of the user's eyes (10), and - Control unit for controlling the deflection unit (17) based on the detection result of the orientation of the eye (10).

14. The eyeglass display system (1) according to the preceding claim. Its features are: The control unit is also designed to control the display unit (14) according to the mapping rules stored in the control unit, wherein the mapping rules define the mapping relationship between each virtual pixel in the virtual image and the corresponding physical pixel in the display unit (14), and the mapping relationship changes according to the orientation of the eye (10).

15. The eyeglass display system according to any one of the preceding two claims (1), Its features are: - In standard operating mode, at least almost all of the micromirror elements (12, 12', 12") are angularly positioned with the eyeglass display system (1) in which they are located, such that light from the display unit (14) is directed to the user's eye (10) only through each of the micromirror elements (12, 12', 12"), and / or - In the power-saving operation mode of the glasses display system (1), the micromirror elements (12, 12', 12") that are not illuminated by the display unit (14) are placed in a predetermined stationary position, and when the eye (10) is stationary - especially when the actuator element (201) is deactivated - in the stationary position, light from the display unit (14) is substantially directed to the user's eye (10).

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