Optical device, AR system and method for compensating for a misalignment between a combiner and projector unit of the AR system

Abstract

The invention relates to an optical device (28) for an AR (Augmented Reality) system (10), for example an AR headset, an AR HUD (Head-Up Display) or the like, with at least one combiner (12) for superimposing an image content artificially generated (augmented) by means of at least one spectrally narrowband AR projector laser beam (14) and projected onto the combiner (12) along an optical path (16) with a real image, in particular an environment image. It is proposed that the optical device (28) includes a compensation element (18) which is designed to compensate, in particular, production- and / or temperature-related detuning of a wavelength tuning between the combiner (12) and a projector unit (20) generating the narrowband AR projector laser beam (14).

Description

State of the art

[0001] An optical device for an AR (augmented reality) system, for example, an AR headset, an AR-HUD (head-up display), or the like, comprising at least one combiner for superimposing an image content artificially generated (augmented) by means of at least one spectrally narrowband AR projector laser beam and irradiated onto the combiner along an optical path, with a real image, in particular an environmental image, has already been proposed. This allows the combiner to achieve high transparency in the view-through path with only minimal interference artifacts. However, for various reasons, the wavelength(s) of the AR projector laser beam may not always match the optimal wavelength(s) of the combiner. Disclosure of the invention

[0002] The invention is based on an optical device for an AR (augmented reality) system, for example an AR headset, an AR-HUD (head-up display) or the like, with at least one combiner for superimposing an image content artificially generated (augmented) by means of at least one spectrally narrowband AR projector laser beam and radiated onto the combiner along an optical path with a real image, in particular an environmental image.

[0003] It is proposed that the optical device comprise a compensation element which is configured to compensate, in particular, for production- and / or temperature-related mismatches in wavelength tuning between the combiner and a projector unit generating the narrowband AR projector laser beam, in particular for wavelength mismatch of the projector unit. This advantageously eliminates the problem of at least temporarily incorrect tuning between the combiner and the AR projector laser beam. This advantageously improves the main function of the AR system, e.g., maximum luminosity of the image content and / or optimal visibility for the real image can be achieved. Furthermore, user comfort can advantageously be increased. Manufacturing tolerances of the projector unit and / or the combiner can advantageously be compensated.

[0004] An AR system is intended, in particular, for a computer-assisted extension of a perception of reality by overlaying artificially generated image content with real images, preferably of the immediate real environment / surroundings of the AR system user. Examples of AR headsets are AR helmets or data glasses, e.g., cycling goggles, diving goggles, motorcycle goggles, aviator goggles, safety goggles, etc. AR HUDs are combined, for example, with vehicle or aircraft windows. In particular, the real image overlaid by the (artificially generated) image content in the AR system is the image of the user's immediate surroundings, which the user would also perceive if they were to deactivate or remove the AR system. "Intended" and / or "equipped" should be understood, in particular, to mean specially programmed, designed, and / or equipped.The fact that an object is intended and / or configured for a specific function should be understood in particular to mean that the object fulfils and / or executes this specific function in at least one application and / or operating state.

[0005] Various combiner types exist for overlaying (artificially generated) image content with real images. In particular, each combiner comprises at least one optical element for directing the artificially generated image content. The optical element can, for example, be designed as a hologram, in particular a volume hologram, preferably a reflection volume hologram. Holograms, especially volume holograms, are generally very angle- and / or wavelength-sensitive. This is advantageous for use in data glasses or similar devices, since the hologram can be designed to diffract / reflect only certain wavelengths from certain angles, e.g., only the wavelengths of the spectrally narrowband AR projector laser beam and / or only light from one direction of incidence of the AR projector laser beam.

[0006] The combiner is preferably designed as a free-space combiner. Free-space combiners are reflective optical elements that are illuminated from behind or from within, reflecting the AR projector laser beam and thereby directing it toward the user's eye. Free-space combiners can, for example, be formed by holographic optical elements (HOEs) integrated into the lens of smart glasses. For example, the artificially generated image is generated by a projector unit in and / or on the temple of the smart glasses, projected onto the lens of the smart glasses, and reflected by the free-space combiner toward the user's eye.

[0007] The AR system in particular comprises the projector unit, which is at least configured to generate / output the AR projector laser beam, in particular to output it in the direction of the combiner or to radiate it onto the combiner. The projector unit could be formed by one or more lasers, in particular diode lasers, preferably VCSELs, preferably ViP-VCSELs. The laser could be designed, for example, as an RGB laser system, as an RGB-IR laser system, or as a monochrome laser system. The projector unit could be formed by one or more light-emitting diodes (LEDs), in particular inorganic LEDs, OLEDs, or SL-LEDs. The LEDs could be designed, for example, as an RGB-LED system or as a monochrome LED system. Combinations of lasers and LEDs are also conceivable.Furthermore, the projector unit could be formed by a gas discharge lamp with narrowband spectral lines or by one or more broadband light sources equipped with color filters. In particular, the projector unit is intended to output the artificially generated image content, which it has received from a computing unit and / or an image generation unit, e.g., the AR system or an external computer system communicating with the AR system, such as a mobile device or a cloud, using the AR projector laser beam. In particular, a path followed by a light beam, in particular the AR projector laser beam, when passing through an optical medium or system is referred to as an optical path.

[0008] The compensation element can be an integral or replaceable part of the projector unit or can be arranged separately from the projector unit.

[0009] It is further proposed that the compensation element be designed as an optical compensation element introduced into the optical path, in particular an optical diffraction grating, a (further) hologram, a light-refracting glass element, a further optical refractive element, such as a lens or the like, and / or a beam focuser and / or shifter. This advantageously allows for simple and / or cost-effective compensation of detuning. This advantageously allows for flexible response to different detunings. This advantageously allows for compensation of manufacturing tolerances of the projector unit, in particular of laser diodes of the projector unit. This advantageously allows for compensation of changes in the wavelengths of the AR projector laser beam caused by environmental influences.

[0010] In this context, it is further proposed that the compensation element be configured to influence the narrowband AR projector laser beam through a wavelength-dependent deflection, a wavelength-dependent shift, and / or a wavelength-dependent focusing. This advantageously allows for reliable and / or finely tunable compensation of detuning. In particular, during the wavelength-dependent deflection, different wavelengths, in particular of the AR projector laser beam, are deflected and / or refracted by the compensation element to different degrees or in different directions. In particular, during the wavelength-dependent shift, different wavelengths, in particular of the AR projector laser beam, are shifted by the compensation element to different degrees or in different directions.In particular, with wavelength-dependent focusing, different wavelengths, especially of the AR projector laser beam, are focused and / or defocused by the compensation element to different degrees or in different directions. The compensation element is designed as a highly dispersive optical element. If the compensation element causes unwanted distortion or shifting of the image content, this unwanted effect can be digitally compensated in an image processing pipeline, particularly in the processing unit and / or the image generation unit, for example, by configuring a distortion correction hardware accelerator (usually already present in the processing unit and / or the image generation unit).

[0011] If the combiner comprises a hologram, in particular a volume hologram, for deflecting, in particular by reflection and / or diffraction, the narrowband AR projector laser beam toward a user eye plane of the AR system, wherein maximum efficiency, in particular maximum diffraction and / or transmission efficiency, of the hologram is wavelength-dependent and / or angle-dependent, the compensation element can advantageously achieve optimal adaptation of the AR projector laser beam, in particular of the wavelength incident on the combiner and / or the beam direction onto the combiner. In particular, the compensation element can be used to correct the wavelength of the AR projector laser beam in the event that the projector unit emits a slightly different wavelength than that intended in the original design of the AR system.In particular, the compensation element can be used to correct the beam direction of the AR projector laser beam in the event that the projector unit has a slightly different emission direction than that intended in the original design of the AR system. In particular, the compensation element is configured to redirect an AR projector laser beam emitted by the projector unit at a wavelength deviating from a design wavelength, thereby ensuring that the Bragg condition is met in the combiner hologram for the deviating wavelength, and thus that the combiner hologram reflects the AR projector laser beam with the deviating wavelength with maximized efficiency.In particular, the compensation element is configured to manipulate, in particular deflect, refract and / or redirect the AR projector laser beam in such a way that an angle of incidence of the AR projector laser beam after manipulation by the compensation element matches an angle of maximum reflection efficiency (Bragg angle) of the hologram of the combiner for the wavelength of the AR projector laser beam, in particular after manipulation by the compensation element, in particular corresponds to the angle of maximum reflection efficiency (Bragg angle) of the hologram of the combiner for the wavelength of the AR projector laser beam, preferably after manipulation by the compensation element.

[0012] Furthermore, it is proposed that the compensation element be designed such that, by influencing the narrowband AR projector laser beam, the narrowband AR projector laser beam, in particular in a wavelength range of at least ±5 nm, preferably at least ±10 nm, preferably at least ±20 nm, and particularly preferably at least ±30 nm, impinges on the hologram of the combiner at an angle of maximum efficiency. This advantageously allows particularly good and / or effective compensation to be achieved. In particular, the Bragg condition known from the literature for the hologram is met at the angle of maximum efficiency. In particular, the angle of maximum efficiency corresponds to the wavelength-dependent reflection gloss angle of the combiner hologram.

[0013] It is also proposed that the compensation element be designed as a thermal compensation element. This advantageously makes it possible to compensate for detunings and / or system errors caused by temperature changes. Such detunings caused by thermal effects, which can be compensated in particular by the thermal compensation element, can be caused, for example, by the projector unit being temperature-sensitive and beam properties of the AR projector light, e.g. the wavelength of the AR projector light, changing over temperature, or by the combiner, in particular the hologram of the combiner, changing its properties, in particular its reflection properties, e.g. the Bragg condition of the hologram of the combiner, changing over temperature. The undesired thermal effects / detunings can be caused, for example, by thermal expansion of parts of the projector unit, e.g.a laser cavity of the projector unit, or the combiner. Advantageously, the thermal compensation element can compensate, among other things, for thermal dependencies of LED or laser diode emission spectra. In particular, a "thermal compensation element" should be understood as a compensation element whose compensation properties / effects can change depending on the temperature, in particular the environment of the optical device. It is conceivable that the thermal compensation element can additionally generate optical compensation. For example, the thermal compensation element could be designed as a lens whose shape and / or refractive power changes with temperature. Such a compensation element would be an optical and thermal compensation element.However, it is also conceivable that the compensation element is purely thermal, i.e., has no optical function, or has an optical function that is independent of temperature. For example, such a compensation element could be a bimetal that changes the orientation and / or position of an optical element depending on the temperature. It is also conceivable that the compensation element is purely optical, i.e. does not react at all to temperature changes, as could be the case with a fixed, strongly dispersive element.

[0014] Furthermore, it is proposed that the thermal compensation element is designed at least partially as a holding element designed to hold the combiner or an optical element introduced into the optical path, in particular an optical diffraction grating, hologram or optical refractive element, such as a lens or the like, which is also designed to change, in a temperature-dependent manner, preferably automatically, at least one relative positioning of the held combiner or optical element within the AR system, e.g. to change a tilt and / or displacement of the held combiner or optical element within the AR system and / or to change a tilt angle and / or a displacement position of the held combiner or optical element within the AR system relative to a beam direction of the AR projector light incident on the combiner or the optical element.This advantageously makes it possible to achieve automatic compensation for undesired thermal detuning. This can advantageously be implemented in a particularly simple and / or cost-effective manner. In particular, the combiner is mounted on the holding element, e.g., glued to the holding element, screwed, bonded or riveted to the holding element, welded to the holding element, or the like. The holding element is preferably connected via a low thermal resistance to the combiner, the optical element, another optical element which forms part of the optical path, or to the projector unit. The optical device / AR system is advantageously designed in such a way (e.g., particularly compact or with good thermal conductivity) that inhomogeneous temperature distributions within the optical device / AR system are kept as low as possible.

[0015] If the holding element has at least one bimetallic holding foot or at least two holding feet with significantly different thermal expansion coefficients, in particular a three- or multi-leg spider mount, a cost-effective, simple, and / or reliable implementation of the automatic thermal detuning compensation can advantageously be enabled. In particular, the holding element is configured to rotate an optical axis of the beam relative to each other along the optical path before and after the combiner, in particular the hologram of the combiner, or before and after the optical element.The rotation generated by the holding element is in particular greater than 0.01 (angular) degree per Kelvin temperature change, preferably greater than 0.02 (angular) degree per Kelvin temperature change, advantageously greater than 0.05 (angular) degree per Kelvin temperature change, particularly advantageously greater than 0.1 (angular) degree per Kelvin temperature change, preferably greater than 0.15 (angular) degrees per Kelvin temperature change and particularly preferably less than 0.2 (angular) degrees per Kelvin temperature change. In particular, the rotation generated by the holding element can be in a range from 0.01 to 0.2 (angular) degrees per Kelvin temperature change. If the optical path contains many (heavy) elements, relatively large forces can act on the holding element. By means of several elements that can be rotated together or independently, e.g. a hologram and a mirror, all other upstream and downstream elements in the optical path of the optical device can remain at constant positions.Advantageously, only the individual optical element (e.g., the hologram and / or the mirror) rests on the support elements. In particular, the thermal compensation element modifies the optical path of the AR projector light such that the optical properties (wavelengths) of the AR projector light and the combiner, especially the hologram of the combiner, match even during / after temperature changes and / or fluctuations.

[0016] It is also proposed that the thermal compensation element be formed at least partially by an optical element whose optical properties, e.g., its reflection angle, transmission angle, and / or refraction angle, are temperature-dependently altered, for example, by a lens whose thickness, radius, and / or refractive index can be thermally altered, by a mirror that is thermally deformable, e.g., by mechanical stresses between different materials, by an optical grating on a substrate with a high thermal expansion coefficient, or by a hologram incorporated into a material with a high thermal expansion coefficient. This advantageously enables a cost-effective, simple, and / or reliable implementation of automatic thermal detuning compensation.In particular, a "high thermal expansion coefficient" should be understood to mean a thermal expansion coefficient that is higher than that of glasses, in particular with the exception of low-dispersion glasses such as N-FK51A. Preferably, the thermal expansion coefficient of the substrate and / or the hologram is greater than 10 ppm / K, advantageously greater than 15 ppm / K, particularly advantageously greater than 50 ppm / K, preferably greater than 100 ppm / K, and particularly preferably less than 1000 ppm / K. For example, the material with the high thermal expansion coefficient could be a metal with a thermal expansion coefficient of more than 12 ppm / K. For example, the material with the high thermal expansion coefficient could be a polymer, preferably with a thermal expansion coefficient of more than 50 ppm / K, particularly preferably more than 100 ppm / K.

[0017] It is also proposed that the combiner be designed as a HOE integrated into a lens of the AR system, in particular an AR headset / data glasses. This advantageously allows for a compact design. The lens can be equipped with or without prescription. In particular, if the lens is equipped with prescription, the lens can form a lens.

[0018] Furthermore, the AR system, for example, an AR headset, an AR HUD (head-up display), or the like, is proposed, comprising the optical device and the projector unit that generates at least the narrowband AR projector light. This advantageously allows for a detuning-robust AR system to be obtained. The AR system could also be implemented, in particular, as binoculars, a telescope, a microscope, a periscope, any type of data glasses, or as a device for ophthalmic examinations.

[0019] Furthermore, it is proposed that the projector unit have an internal or external computing unit which is at least configured to correct, in particular digitally, the distortion and / or shift of the image content artificially generated by means of the spectrally narrowband AR projector laser beam of the projector unit, caused by compensating for the detuning of the wavelength tuning between the combiner and the projector unit, in particular by digital equalization, shifting and / or distortion correction. This can advantageously achieve a particularly high level of user comfort. Advantageously, a display of image content that is at least substantially independent of temperature fluctuations can be enabled. A "computing unit" is to be understood in particular as a unit with an information input, an information processing unit and an information output.The computing unit advantageously comprises at least one processor, a memory, input and output means, further electrical components, an operating program, control routines, control routines, and / or calculation routines. The components of the computing unit are preferably arranged on a common circuit board and / or advantageously arranged in a common housing. Alternatively, however, the computing unit can also be designed as a distributed computing unit, e.g., a cloud or the like. The computing unit preferably includes the distortion correction hardware accelerator.

[0020] Furthermore, a method for compensating for a wavelength mismatch, particularly one caused by production and / or temperature, between the combiner and the projector unit of the AR system generating a narrowband AR projector light is proposed. The image content artificially generated (augmented) by the combiner using at least the spectrally narrowband AR projector laser beam of the AR projector light and irradiated onto the combiner along the optical path is superimposed with a real image, particularly an ambient image, and the wavelength mismatch between the combiner and the projector unit, particularly the wavelength mismatch of the projector unit, is compensated for by the optical and / or thermal compensation element. This advantageously eliminates the problem of at least temporarily incorrect matching between the combiner and the AR projector laser beam.This can advantageously improve the main function of the AR system, e.g. maximum luminosity of the image content and / or optimal visibility for the real image can be achieved.

[0021] The optical device according to the invention, the AR system according to the invention, and the method according to the invention are not intended to be limited to the application and embodiment described above. In particular, the optical device according to the invention, the AR system according to the invention, and the method according to the invention may have a number of individual elements, components, and units as well as method steps that differs from the number stated herein to fulfill a functionality described herein. Furthermore, in the value ranges specified in this disclosure, values ​​within the stated limits are also to be considered disclosed and can be used arbitrarily. drawing

[0022] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0023] They show: Fig. 1 schematically shows an exemplary AR (Augmented Reality) system with an optical device, Fig. 2 schematically shows an exemplary optical device with an optical and / or thermal compensation element, Fig. 3a schematically shows an example of a thermal compensation element at a first temperature T1, Fig. 3b the exemplary thermal compensation element of the Fig. 3a at a second temperature T2 and Fig. 4 a schematic flow diagram of a method with the optical device. Description of the embodiment

[0024] The Fig. 1 schematically shows an exemplary AR (Augmented Reality) system 10. The illustrated AR system 10 is designed as an AR headset, more precisely, data glasses. The AR system 10 has, for example, a virtual retinal display. The virtual retinal display is intended for projecting an artificially generated image content directly onto a retina 32 of a user eye 34 of a user of the AR headset. The AR system 10 has a projector unit 20. The projector unit 20 from the exemplary embodiment of the Fig. 1 is integrated into a temple of the data glasses. The projector unit 20 is provided for generating an AR projector light. The AR projector light contains the artificially generated image content. The AR projector light comprises at least one AR projector laser beam 14. The AR projector laser beam 14 is spectrally narrowband. The AR projector light can comprise several (differently colored) narrowband AR projector laser beams 14. The AR system 10 comprises a computing unit 30. The computing unit 30 is provided for generating the image content. After being generated by the computing unit 30, the image content is transmitted to the projector unit 20 for output via the AR projector laser beam 14.

[0025] The AR system 10 comprises an optical device 28. The optical device 28 comprises a combiner 12. The combiner 12 is in the embodiment of the Fig. 1 is designed as a (holographically reflective) free-space combiner. The combiner 12 from the embodiment of the Fig. 1 is formed by a hologram, in particular a volume hologram, preferably a holographic optical element (HOE). The combiner 12 from the embodiment of Fig. 1 is embedded / integrated into a spectacle lens of the data glasses. The combiner 12 is configured to superimpose the artificially generated (augmented) image content by means of the AR projector laser beam 14 with a real image, in particular an environmental image. The AR projector laser beam 14 propagates along an optical path 16 of the optical device 28. The optical device 28 specifies the optical path 16 of the AR system 10, in particular by means of optical elements. The combiner 12 is provided to redirect at least a portion of the AR projector light (by reflection) toward a user eye plane 22 of the AR system 10 / in the direction of the user eye 34. A maximum efficiency, in particular a maximum diffraction efficiency, of the hologram of the combiner 12 is wavelength-dependent. A maximum efficiency, in particular a maximum diffraction efficiency, of the hologram of the combiner 12 is angle-dependent.The combiner 12 is designed to transmit at least a portion of the ambient light (white light) toward the user's eye 34. The combiner 12, in particular the hologram of the combiner 12, has a spectrally narrowband range of maximum reflection. With optimal tuning of the AR system 10, the range of maximum reflection of the combiner 12 is wavelength-tuned to the wavelength range of the narrowband AR projector laser beam 14. A non-optimal tuning of the combiner 12 to the AR projector laser beam 14, in particular the projector unit 20, is called detuning. This detuning can be due to production and / or temperature-related factors, for example.

[0026] The Fig. 2 schematically shows an exemplary optical device 28. The optical device 28 has a compensation element 18. The compensation element 18 is configured to compensate for the detuning of the wavelength tuning between the combiner 12 and the projector unit 20 generating the narrowband AR projector laser beam 14. The compensation element 18 is embodied as an optical compensation element 18. The compensation element 18 is introduced into the optical path 16 of the optical device 28. The optical compensation element 18 is embodied, for example, as a hologram, in particular a transmission hologram. Alternatively, the optical compensation element 18 could also be embodied as an optical diffraction grating or an optical refractive element, such as a lens or the like. The optical compensation element 18 is designed to influence the narrowband AR projector laser beam 14 by a wavelength-dependent deflection.Alternatively or additionally, the optical compensation element 18 could also be configured to perform a wavelength-dependent shift and / or wavelength-dependent focusing in addition to influencing the narrowband AR projector laser beam 14. The compensation element 18 is configured such that, by influencing the narrowband AR projector laser beam 14, the narrowband AR projector laser beam 14 impinges on the hologram of the combiner 12 at an angle of maximum efficiency (glancing angle of the hologram). The compensation element 18 is configured such that this applies in a wavelength range of at least ±10 nm.

[0027] In the Fig. 2 shows a schematic and simplified representation of two exemplary beam paths of the AR projector laser beam 14 in the optical device 28. A solid line represents, by way of example, the optical path 16 of an optimally coordinated combination of projector unit 20 and combiner 12. If, for example, the AR projector laser beam 14 has a wavelength that deviates from the optimal coordination, or if, for example, the hologram of the combiner 12 has an angle of maximum efficiency at a wavelength that deviates from the optimal coordination, the compensation element 18 deflects or redirects the AR projector laser beam 14 depending on the wavelength in such a way that the angle of maximum efficiency of the hologram of the combiner 12 and the AR projector laser beam 14 match again.Alternatively, the compensation element 18 could also modify the wavelength of the AR projector laser beam 14 to achieve the matching of the angle of maximum efficiency of the hologram of the combiner 12 and the AR projector laser beam 14.

[0028] The compensation element 18 is designed, in particular alternatively or in addition to the design as an optical compensation element 18, as a thermal compensation element 18. The thermal compensation element 18 is formed at least partially by an optical element that changes its optical properties depending on the temperature. In the Fig. In the case illustrated by way of example in Figure 2, the thermal compensation element 18 is formed by a hologram embedded in a material with a high coefficient of thermal expansion. Alternatively, the thermal compensation element 18 could be formed by a thermally variable lens with a thickness, radius, and / or refractive index, by a thermally deformable mirror, or by an optical grating on a substrate with a high coefficient of thermal expansion.

[0029] The projector unit 20 has a computing unit 30. The computing unit 30 is embodied as an internal computing unit 30. Alternatively, the computing unit 30 could also be an external centralized computing unit 30, e.g., a mobile device such as a smartphone, or an external distributed computing unit 30, e.g., a cloud. The computing unit 30 is configured at least to digitally correct distortion and / or shifting of the image content artificially generated by the spectrally narrowband AR projector laser beam 14 of the projector unit 20, caused by the compensation of the detuning of the wavelength tuning between the combiner 12 and the projector unit 20, generated via the compensation element 18.

[0030] The Fig. 3a and Fig. 3b schematically and by way of example, show a possible compensation element 18 at two different temperatures. The optical device 28 has a holding element 24. The thermal compensation element 18 is at least partially formed as the holding element 24. The holding element 24 is configured to hold the combiner 12 or an optical element introduced into the optical path 16, in particular an optical diffraction grating, hologram, or optical refractive element, such as a lens or the like. The holding element 24 is designed, for example, as a 3-leg spider holder 26. Alternatively, the holding element 24 could also have more or fewer than 3 legs. At least two holding feet of the 3-leg spider holder 26 have significantly different thermal expansion coefficients. A temperature change therefore leads, for example, to a tilting of the combiner 12 / optical element, which is held by the holding element 24 (cf. Fig. 3b). The thermal compensation element 18 is thus also configured to automatically and temperature-dependently change at least one relative positioning of the mounted combiner 12 or optical element within the AR system 10. This allows, in particular, the beam direction on an output side of the combiner 12 or optical element to change temperature-dependently. As an alternative to the 3-leg spider mount 26, a design of the holding element 24 as a bimetallic holding base or as a combination of several bimetallic holding bases would also be conceivable.

[0031] The Fig.4 shows a schematic flow diagram of a method for compensating for a wavelength tuning mismatch between the combiner 12 and the projector unit 20 generating the narrowband AR projector light, in particular due to production and / or temperature. In at least one method step 36, the combiner 12 overlays the image content artificially generated (augmented) by means of the spectrally narrowband AR projector laser beam 14 of the AR projector light and radiated onto the combiner 12 along the optical path 16 with the real image coming from outside.In this case, the optimal wavelength of the combiner 12 and the wavelength of the AR projector laser beam 14 and / or the angular relationship with which the AR projector laser beam 14 impinges on the combiner 12 are modified by means of the optical compensation element 18 and / or by means of the thermal compensation element 18 in a manner that leads to a compensation of the detuning(s) in the event of a mismatch in the wavelength tuning between the combiner 12 and the projector unit 20 and / or a mismatch in the angular tuning between the combiner 12 and the AR projector laser beam 14.

Claims

[1] Optical device (28) for an AR (Augmented Reality) system (10), for example an AR headset, an AR-HUD (Head-Up Display) or the like, with at least one combiner (12) for superimposing an image content artificially generated (augmented) by means of at least one spectrally narrowband AR projector laser beam (14) and radiated onto the combiner (12) along an optical path (16) with a real image, in particular an environmental image, characterized by a compensation element (18) which is designed to compensate, in particular, production- and / or temperature-related, detuning of a wavelength tuning between the combiner (12) and a projector unit (20) generating the narrowband AR projector laser beam (14). [2] Optical device (28) according to claim 1, characterized bythat the compensation element (18) is designed as an optical compensation element (18) introduced into the optical path (16), in particular an optical diffraction grating, a hologram or an optical refractive element, such as a lens or the like. [3] Optical device (28) according to claim 2, characterized by that the compensation element (18) is designed to influence the narrow-band AR projector laser beam (14) by a wavelength-dependent deflection, by a wavelength-dependent shift and / or by a wavelength-dependent focusing. [4] Optical device (28) according to claim 3, characterized byin that the combiner (12) comprises a hologram, in particular a volume hologram, for deflecting, in particular by reflection and / or diffraction, the narrow-band AR projector laser beam (14) in the direction of a user eye plane (22) of the AR system (10), wherein a maximum efficiency, in particular a maximum diffraction and / or transmission efficiency, of the hologram is wavelength-dependent and / or angle-dependent. [5] Optical device (28) according to claim 4, characterized by that the compensation element (18) is designed such that by influencing the narrowband AR projector laser beam (14) thereof, the narrowband AR projector laser beam (14), in particular in a wavelength range of at least ±5 nm, preferably at least ±10 nm, preferably at least ±20 nm and particularly preferably at least ±30 nm, strikes the hologram of the combiner (12) at an angle of maximum efficiency. [6] Optical device (28) according to one of the preceding claims, characterized by that the compensation element (18) is designed as a thermal compensation element (18). [7] Optical device (28) according to claim 6, characterized by in that the thermal compensation element (18) is at least partially designed as a holding element (24) designed to hold the combiner (12) or an optical element introduced into the optical path (16), in particular an optical diffraction grating, hologram or optical refractive element, such as a lens or the like, which is also designed to change at least one relative positioning of the held combiner (12) or optical element within the AR system (10) in a temperature-dependent manner, preferably automatically. [8] Optical device (28) according to claim 7, characterized bythat the holding element (24) has at least one bimetallic holding foot or at least two holding feet with substantially different thermal expansion coefficients, in particular a 3- or multi-leg spider holder (26). [9] Optical device (28) according to one of claims 6 to 8, characterized by that the thermal compensation element (18) is formed at least partially by an optical element whose optical properties change depending on the temperature, for example by a lens whose thickness, radius and / or refractive index is thermally variable, by a thermally deformable mirror, by an optical grating on a substrate with a high thermal expansion coefficient or by a hologram introduced into a material with a high thermal expansion coefficient. [10] Optical device (28) according to one of the preceding claims, characterized bythat the combiner (12) is designed as a holographic optical element (HOE) integrated into a spectacle lens of the AR system (10), in particular an AR headset / data glasses. [11] AR system (10), for example an AR headset, an AR-HUD (Head-Up Display) or the like, with an optical device (28) according to one of the preceding claims and with a projector unit (20) generating at least one narrow-band AR projector laser beam (14). [12] AR system (10) according to claim 11, characterized byin that the projector unit (20) has an internal or external computing unit (30) which is at least configured to correct, in particular digitally, the distortion and / or shift of the image content artificially generated by means of the spectrally narrowband AR projector laser beam (14) of the projector unit (20) caused by a compensation of the detuning of the wavelength tuning between the combiner (12) and the projector unit (20). [13] Method for compensating for a detuning, in particular production- and / or temperature-related, of a wavelength tuning between a combiner (12) and a projector unit (20) generating a narrowband AR projector light of an AR system (10), in particular according to one of claims 11 or 12, wherein an image content artificially generated (augmented) by means of at least one spectrally narrowband AR projector laser beam (14) of the AR projector light and irradiated onto the combiner (12) along an optical path (16) is superimposed with a real image, in particular an environmental image, characterized by that the detuning of the wavelength tuning between the combiner (12) and the projector unit (20) is compensated by means of an optical and / or thermal compensation element (18).

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