Optoelectronic arrangement and method for tracking the movement of an object being a human eye using an optoelectronic arrangement

Abstract

An optoelectronic arrangement (1) comprising: an optical element (10) and a detector element (20) is described herein. The optical element (10) is configured to superimpose a plurality of images of different object regions (301) of an object (30) in a combined image. The optical element (10) is arranged between the object (30) and the detector element (20) along an optical path extending from the object (30) to the detector element (20). The detector element (20) is configured to receive the combined image of the object regions (301). Further, a method for tracking the movement of an object being a human eye using an optoelectronic arrangement (1) is provided.

Description

[0001] Description

[0002] OPTOELECTRONIC ARRANGEMENT AND METHOD FOR TRACKING THE MOVEMENT OF AN OBJECT BEING A HUMAN EYE US ING AN OPTOELECTRONIC ARRANGEMENT

[0003] The present application relates to an optoelectronic arrangement and a method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement . In particular, the optoelectronic arrangement is configured to detect electromagnetic radiation .

[0004] It is an obj ect of the present disclosure to provide an optoelectronic arrangement having improved optical characteristics and a reduced lateral extension .

[0005] A further obj ect is to provide a method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement having improved optical characteristics and an advantageously small footprint .

[0006] These obj ects are achieved by devices and a method according to the independent patent claims . Advantageous embodiments and further developments of the devices and the method are the subj ect of the dependent patent claims and are furthermore apparent from the following description and the figures .

[0007] According to at least one embodiment of the optoelectronic arrangement , the optoelectronic arrangement comprises an optical element . The optical element is preferably radiation permeable for electromagnetic radiation in the visible spectral range . Here and in the following, the visible spectral range in particular extends from 380 nm to 780 nm. For example, the optical element is formed with a translucent polymer or glass. Furthermore, the optical element can be formed as a multi-layered element comprising several layers of different materials.

[0008] According to at least one embodiment of the optoelectronic arrangement, the optoelectronic arrangement comprises a detector element. The detector element is in particular suitable to detect an electromagnetic radiation. Preferably, the detector element comprises a plurality of light sensitive regions in a grid shaped arrangement. In particular, the detector element is configured to achieve a spatially resolved detection of electromagnetic radiation.

[0009] According to at least one embodiment of the optoelectronic arrangement, the optical element is configured to superimpose a plurality of images of different object regions of an object in a combined image. For example, the optical element adds up the plurality of images of different object regions in the combined image. An object region can be a spatially delimited region of an object. For example, an object region has an outer shape of an ellipsoid, a circle, a rectangle or a hexagon.

[0010] According to at least one embodiment of the optoelectronic arrangement, the optical element is arranged between the object and the detector element along an optical path extending from the object to the detector element. The optical path in particular describes a path of electromagnetic radiation which propagates between the object and the detector element. For example, ambient light which impinges at the obj ect propagates along the optical path to reach the detector .

[0011] According to at least one embodiment of the optoelectronic arrangement , the detector element is configured to receive the combined image of the obj ect regions . In particular, the detector element is configured to achieve a spatially resolved detection of the combined image . Advantageously, the detector element can determine di f ferent levels of optical intensity in di f ferent regions .

[0012] According to at least one embodiment the optoelectronic arrangement , the optoelectronic arrangement comprises :

[0013] - an optical element and a detector element , wherein

[0014] - the optical element is configured to superimpose a plurality of images of di f ferent obj ect regions of an obj ect in a combined image ,

[0015] - the optical element is arranged between the obj ect and the detector element along an optical path extending from the obj ect to the detector element , and

[0016] - the detector element is configured to receive the combined image of the obj ect regions .

[0017] An optoelectronic arrangement described herein is , inter alia, based on the following considerations : Imaging based obj ect tracking sensors , such as eye-tracking sensors , can inter alia require a direct illumination of an obj ect as well as a direct imaging of the same area . State of the art algorithms for eye-tracking arrangements , rely on the information of the pupil location and the position of the specular reflection of the light source from the cornea to assess a gaze vector . In order to gain these parameters a camera with a large field of view is needed somewhere in front of the user that provides images of the eye that can be processed . The camera is situated usually below the eyes of the user providing an upward tilted image of the eye and its surroundings . The accuracy with which the eye is tracked inter alia depends on the resolution of the camera, the optics of the camera and the software approach used . The position and the optics of the camera combined with the resolution of the image sensor determine the number of pixels the eye ef fectively uses in the image . In addition, the illumination necessary is usually provided by several light emitting diodes next to the camera or situated in a ring around the eye , which can disturb a user .

[0018] The optoelectronic arrangement described herein is , among other things , based on the idea of using an optical element to get access to a plurality of di f ferent obj ect regions of a pupil plane , while having less distracting components within the field of view of the user . The latter is achieved by adding a detector element on the return path of the optical element . The optical element inter alia condenses the full information into a combined image of a much smaller format . Since the information about an eye rotation in all of these images is , i f not 100% the same , at least very similar, the actual information is still contained inside the combined image . Since a gaze vector or pupil position is of a much smaller dimensionality than the information contained inside the combined image , the inference of the pupil position should be feasible .

[0019] I f used in reverse the optical element provides both an extended eye-box as well as a strong illumination ef ficiency . The optical element described provides a transparent , see through optical component , using spectrally narrow-band and angular selective features in order to render it virtually invisible to a user of augmented or mixed reality glasses. The magnified view of the pupil allows for a much earlier and better detection of eye movement than a zoomed out view could provide. This could result in a much more accurate determination of miniscule movement. Moreover, the use of condensed information of the combined image allows access to all the advantages usually associated with compressed sensing, e.g. smaller power consumption and smaller detector elements. Furthermore, the magnified view of the pupil generated by the optoelectronic arrangement can be used for identifying a user based on the unique image of his iris. For example, the optoelectronic arrangement can thus be used as a security enabling device.

[0020] According to at least one embodiment the optoelectronic arrangement further comprises a projector element defining a further optical path extending from the projector element to the object, wherein the optical element is arranged along the further optical path between the projector element and the object. In particular, the projector element is configured to project a display image. For example, the projector element comprises a laser light source. Advantageously, the projector element emits electromagnetic radiation having a desired wavelength in the visible spectral range.

[0021] According to at least one embodiment of the optoelectronic arrangement, the optical element is configured to distribute a display image generated by the projector element into the different object regions on the object. Advantageously, the distribution of the display image into a plurality of laterally separated object regions can enlarge a so called eye-box for a user of the optoelectronic arrangement. Here and in the following, an eye-box is to be understood as a virtual region in which the user can see the display image . A larger eye-box enables the user to see the display image in a larger part of his natural field of view .

[0022] According to at least one embodiment of the optoelectronic arrangement , the optical element is configured to distribute the display image into at least 2 , preferably at least 5 , and particularly preferably at least 10 di f ferent obj ect regions . A higher number of obj ect regions can increase the si ze of an eye-box and enable a better user experience .

[0023] According to at least one embodiment of the optoelectronic arrangement , the optical element is configured to distribute the display image into at least 19 di f ferent obj ect regions . A higher number of obj ect regions can increase the si ze of an eye-box and enable a better user experience .

[0024] According to at least one embodiment of the optoelectronic arrangement , a deflector element is arranged in the optical path between the optical element and the detector element , and configured to deflect light incident from the obj ect to the detector element . By means of the deflector element , electromagnetic radiation reflected by the obj ect and returning through the optical element can be deflected to leave the further optical path between the proj ector element and the obj ect .

[0025] According to at least one embodiment of the optoelectronic arrangement , the deflector element is a beam splitter . For example , the deflector element is configured to deflect a part of an electromagnetic radiations intensity of an incident beam . Alternatively, the deflector element selects an electromagnetic radiation based on a polari zation property . For example , the deflector element only deflects an incident electromagnetic radiation of right-handed circular polari zation and transmits an incident electromagnetic radiation of left-handed circular polari zation .

[0026] According to at least one embodiment of the optoelectronic arrangement , the deflector element comprises a dichroic mirror . In particular, the deflector element is configured to deflect an incident electromagnetic radiation having a wavelength of a certain wavelength range . For example , the deflector element is configured to deflect infrared radiation but to transmit electromagnetic radiation in the visible spectral range .

[0027] According to at least one embodiment of the optoelectronic arrangement , the detector element comprises a photodiode array, a CMOS or CCD image sensor . Photodiode arrays comprise a plurality of photo diodes arranged in a common plane . CMOS sensors in particular are active-pixel sensors which are configured to detect an image via a plurality of metal oxide semiconductor diodes . CCD image sensors can comprise a plurality of capacitors configured to detect an optical image . Advantageously, photo diode arrays can be very fast and thus detect an optical signal in a short amount of time .

[0028] According to at least one embodiment of the optoelectronic arrangement , the obj ect is a pupil of a human eye . In particular, the proj ector element is configured to proj ect an image into the eye . The proj ection of an image into the eye combined with a detection of a gaze vector enables the use of the optoelectronic arrangement in an augmented reality device . According to at least one embodiment of the optoelectronic arrangement , an optical system is arranged upstream of the detector element . In particular, the optical system comprises at least one lens . For example , the optical system is configured to magni fy an image before it reaches the detector element . For example , the detector element together with the optical system forms a camera .

[0029] According to at least one embodiment of the optoelectronic arrangement , an infrared light source is arranged upstream of the obj ect . In particular, the infrared light source comprises a light emitting luminescence diode . The infrared light source in particular comprises a laser diode , a superluminescent diode or a light emitting diode . For example , the infrared light source is arranged in a common emission plane with the proj ector element . The emission plane is in particular a plane in which the proj ector element emits electromagnetic radiation which creates the display image .

[0030] According to at least one embodiment of the optoelectronic arrangement , the infrared light source emits electromagnetic radiation in the near infrared wavelength range . Here and in the following, the near infrared range is to be understood as a wavelength range between 780 nm and 1500 nm .

[0031] According to at least one embodiment of the optoelectronic arrangement , the infrared light source emits electromagnetic radiation having a coherence length of at most 100 pm . Electromagnetic radiation having a shorter coherence length than 100 pm can increase unwanted interference ef fects . Advantageously, the infrared light source is a superluminescent diode which shows a narrow spectral bandwidth and a short coherence length compared to a laser diode .

[0032] Furthermore , a method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement is also disclosed . The method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement is particularly suitable for operating an optoelectronic arrangement described herein . This means that all features disclosed in connection with the optoelectronic arrangement are also disclosed for the method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement and vice versa .

[0033] According to at least one embodiment of the method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement the method comprises receiving a first combined image and at least a second combined image , wherein the second combined image is taken subsequently to the first combined image . For example , an image is taken by evaluating and storing the output signals of the detector element .

[0034] According to at least one embodiment of the method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement the method comprises computing a movement of the eye based on a comparison of the first and second combined image . In particular, the computation comprises a comparison of each pixel value of the first and second combined image . For example , the comparison could use an arithmetic operation such as a subtraction of each pixel value in the first combined image with a corresponding pixel value in the second combined image . According to at least one embodiment of the method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement the method comprises the steps of :

[0035] - receiving a first combined image and at least a second combined image , wherein the second combined image is taken subsequently to the first combined image ,

[0036] - computing a movement of the eye based on a comparison of the first and second combined image .

[0037] According to at least one embodiment of the method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement , the step of computing the movement of the eye is performed by using an algorithm comprising an arti ficial intelligence method . In particular, machine learning is used to determine a correlation between a movement of the eye and the resulting gaze vector with a change of the first and second combined image .

[0038] According to at least one embodiment of the method for tracking the movement of an obj ect being a human eye using an optoelectronic arrangement , the step of computing is performed in a processing unit arranged in the detector element . In particular, the processing unit comprises a storage and a processor unit to perform a step of computing .

[0039] An optoelectronic arrangement described herein is particularly suitable for use in Eye tracking systems for AR / VR wearable headsets .

[0040] Further advantages and advantageous designs and further developments of the optoelectronic arrangement will become apparent from the following exemplary embodiments , which are described below in association with the figures .

[0041] In the figures :

[0042] Figure 1 shows a schematic cross-sectional view of an optoelectronic arrangement according to a first exemplary embodiment ,

[0043] Figure 2 shows a schematic cross-sectional view of an optoelectronic arrangement according to a second exemplary embodiment ,

[0044] Figure 3 shows a schematic cross-sectional view of an optoelectronic arrangement according to a third exemplary embodiment ,

[0045] Figure 4 shows a schematic cross-sectional view of an optoelectronic arrangement according to a fourth exemplary embodiment ,

[0046] Figure 5 shows a schematic cross-sectional view of an optical element ,

[0047] Figure 6 shows a first image of an obj ect ,

[0048] Figure 7 shows a plurality of obj ect regions of the first image , and

[0049] Figure 8 shows a combined image from the superposition of the plurality of obj ect regions of the first regions . Identical , similar or equivalent elements are marked with the same reference signs in the figures . The figures and the proportions of the elements represented in the figures among each other are not to be considered as true to scale . Rather, individual elements may be oversi zed for better representability and / or comprehensibility .

[0050] Figure 1 shows a schematic cross-sectional view of an optoelectronic arrangement 1 according to a first exemplary embodiment . The optoelectronic arrangement 1 comprises an optical element 10 and a detector element 20 . The optical element 10 is preferably radiation permeable for electromagnetic radiation in the visible spectral range . The visible spectral range in particular extends from 380 nm to 780 nm . For example , the optical element 10 is formed with a translucent polymer or glass . Furthermore , the optical element 10 can be formed as a multi-layered element comprising several layers of di f ferent materials as shown in more detail in figure 5 .

[0051] The detector element 20 is in particular suitable to detect an electromagnetic radiation . Preferably, the detector element 20 comprises a plurality of light sensitive regions in a grid shaped arrangement . In particular, the detector element 20 is configured to achieve a spatially resolved detection of electromagnetic radiation .

[0052] The optical element 1 is configured to superimpose a plurality of images of di f ferent obj ect regions 301 of an obj ect 30 in a combined image . The obj ect 30 is a pupil of a human eye . For example , the optical element 10 adds up the plurality of images of di f ferent obj ect regions 301 in the combined image . An obj ect region 301 is a spatially delimited region of an obj ect 30 . For example , an obj ect region 301 has an outer shape of an ellipsoid, a circle , a rectangle or a hexagon . The optical element 1 is arranged between the obj ect 30 and the detector element 20 along an optical path extending from the obj ect 30 to the detector element 20 . The optical path in particular describes a path of electromagnetic radiation which propagates between the obj ect 30 and the detector element 20 . For example , ambient light which impinges at the obj ect 30 propagates along the optical path to reach the detector 20 .

[0053] The detector element 20 is configured to receive the combined image of the obj ect regions 301 . In particular, the detector 20 element is configured to achieve a spatially resolved detection of the combined image . Advantageously, the detector element 20 can determine di f ferent levels of optical intensity in di f ferent regions .

[0054] The detector element 20 comprises a CMOS or CCD image sensor . CMOS sensors in particular are active-pixel sensors which are configured to detect an image via a plurality of metal oxide semiconductor diodes . CCD image sensors can comprise a plurality of capacitors configured to detect an optical image .

[0055] Figure 2 shows a schematic cross-sectional view of an optoelectronic arrangement 1 according to a second exemplary embodiment . The second exemplary embodiment is essentially equal to the first exemplary embodiment shown in figure 1 . Additionally, the optoelectronic arrangement 1 comprises a projector element 50 defining a further optical path extending from the projector element 50 to the object 30. The optical element 10 is arranged along the further optical path between the projector element 50 and the object 30. In particular, the projector element 50 is configured to project a display image. For example, the projector element 50 comprises a laser light source. The projector element 50 is configured to project an image into the eye. The projection of an image into the eye combined with a detection of a gaze vector enables the use of the optoelectronic arrangement 1 in an augmented reality device.

[0056] The optical element 10 is configured to distribute a display image generated by the projector element 50 into the different object regions 301 on the object 30. Advantageously, the distribution of the display image into a plurality of laterally separated object regions 301 can enlarge a so called eye-box for a user of the optoelectronic arrangement 1. The eye-box is to be understood as a virtual region in which the user can see the display image. A larger eye-box enables the user to see the display image in a larger part of his natural field of view.

[0057] The optical element 10 is configured to distribute the display image into at least 10, preferably at least 19 different object regions 301. A higher number of object regions 301 can increase the size of an eye-box and enable a better user experience.

[0058] Furthermore, a deflector element 40 is arranged in the optical path between the optical element 10 and the detector element 50. The deflector element 40 is configured to deflect light incident from the object 30 to the detector element 20. By means of the deflector element 40 , electromagnetic radiation reflected by the obj ect 30 and returning through the optical element 10 can be deflected to leave the further optical path between the proj ector element 50 and the obj ect 30 .

[0059] The deflector element 40 is a beam splitter . For example , the deflector element 40 is configured to deflect a part of an electromagnetic radiations intensity of an incident beam . Alternatively, the deflector element 40 selects an electromagnetic radiation based on a polari zation property . For example , the deflector element 40 only deflects an incident electromagnetic radiation of right-handed circular polari zation and transmits an incident electromagnetic radiation of left-handed circular polari zation .

[0060] Alternatively, the deflector element 40 comprises a dichroic mirror . In particular, the deflector element 40 is configured to deflect an incident electromagnetic radiation having a wavelength of a certain wavelength range . For example , the deflector element 40 is configured to deflect infrared radiation but to transmit electromagnetic radiation in the visible spectral range .

[0061] Figure 3 shows a schematic cross-sectional view of an optoelectronic arrangement according to a third exemplary embodiment . The second exemplary embodiment is essentially equal to the second exemplary embodiment shown in figure 2 . Additionally, the optoelectronic arrangement 1 comprises an optical system 201 which is arranged upstream of the detector element 20 . In particular, the optical system 201 comprises at least one lens . For example , the optical system 201 is configured to magni fy an image before it reaches the detector element 20 . For example , the detector element 20 together with the optical system 201 forms a camera .

[0062] Figure 4 shows a schematic cross-sectional view of an optoelectronic arrangement according to a fourth exemplary embodiment . The second exemplary embodiment is essentially equal to the second exemplary embodiment shown in figure 2 . Additionally, the optoelectronic arrangement 1 comprises an infrared light source 70 which is arranged upstream of the obj ect 30 . In particular, the infrared light source 70 comprises a light emitting diode . The infrared light source 70 emits electromagnetic radiation in the near infrared wavelength range . Here and in the following, the near infrared range is to be understood as a wavelength range between 780 nm and 1500 nm . The infrared light source 70 is arranged in a common emission plane E with the proj ector element 50 . The emission plane E is in particular a plane in which the proj ector element 50 emits electromagnetic radiation which creates the display image .

[0063] Figure 5 shows a schematic cross-sectional view of an optical element 10 . The optical element 10 comprises a first or front side 1051 facing towards the proj ector element 20 and a second or rear side 1052 facing towards the obj ect 30 .

[0064] The optical element 10 includes a volume phase hologram ( short : VPH) 1040 and an optical combiner 1050 .

[0065] The optical combiner 1050 is formed as a "reflective pancake" optical combiner for collimating a spread image light and for reflecting a collimated light back through the VPH 1040 to form collimated light R . The collimated light R can further propagate to an eye of a user to provide an expanded eye-box at the eye of the user . The optical combiner 1050 comprises a polari zation-dependent reflector 1054 , a retarder 1056 which comprises , or which is configured to act as , a quarter-wave plate , and an optically-powered reflector 1058 . The optically-powered reflector 1058 comprises a curved transparent body or substrate 1060 having a dichroic reflective coating 1062 disposed on a front convex surface thereof .

[0066] The volume phase hologram 1040 is an optical spreader in the form of a transmissive volume phase hologram for fanning-out a proj ected image light 1018 emitted by the proj ector element 50 to spread image light into di f ferent obj ect regions 301 .

[0067] The dichroic reflective coating 1062 is configured to be highly reflecting in one or more narrow spectral bands , each narrow spectral band being arranged around a corresponding wavelength of the image light 1018 emitted by the proj ector element 50 , but to transmit light at other wavelengths . For example , the dichroic reflective coating 1062 may be configured to have a reflectance in each spectral band of 90% or greater, 95% or greater, or 99% or greater . The dichroic reflective coating 1062 is in particular configured to reflect ambient light at wavelengths inside the one or more narrow spectral bands but to transmit ambient light at wavelengths outside the one or more narrow spectral bands .

[0068] The polari zation-dependent reflector 1054 and the dichroic reflective coating 1062 of the optically-powered reflector 1058 define an optical cavity, wherein the retarder 1056 is located in the optical cavity . Moreover, the polari zationdependent reflector 1054 and the optically-powered reflector 1058 are arranged so that the polari zation-dependent reflector 1054 is located in an optical path between the VPH 1040 and the optically-powered reflector 1058 . The retarder 1056 and the optically-powered reflector 1058 are separated by an air gap 1064 .

[0069] The optical element 10 further includes a circular polari zer 1070 disposed on the dichroic reflective coating 1062 of the optically-powered reflector 1058 . During intended use , the optical combiner 1050 ef fectively combines the ambient light which is incident on the front side 1051 of the optical combiner 1050 with the collimated light which exits the rear side 1052 of the optical combiner 1050 .

[0070] Speci fically, the circular polari zer 1070 imparts a circular polari zation to the ambient light . The circularly-polari zed ambient light is incident on the front side 1051 of the optical element 10 defined by the dichroic reflective coating 1062 of the optically-powered reflector 1058 . The dichroic reflective coating 1062 transmits , towards the retarder 1056 , the wavelengths of the circularly-polari zed ambient light which fall outside the one or more narrow spectral bands over which the dichroic reflective coating 1062 is highly reflecting .

[0071] The retarder 1056 converts the circularly-polari zed ambient light transmitted by the dichroic reflective coating 1062 to linearly-polari zed ambient light having a linear polari zation which is aligned with a polari zation transmission axis of the polari zation-dependent reflector 1054 so that the polari zation-dependent reflector 1054 transmits the linearly- polari zed ambient light towards the expanded eye box . Use of the circular polari zer 1070 at least partially suppresses the reflection of ambient light from the polari zation-dependent reflector 1054 thereby at least partially suppressing the formation of any ghost images of the scene at the eye box .

[0072] Figure 5 illustrates the reflection and collimation of linearly-polari zed image light 1018 and replication of the image for the case of the linearly-polari zed principal ray of the linearly-polari zed image light 1018 . For the purposes of the following description, it is assumed that the linearly- polari zed image light 1018 , and therefore that the linearly- polari zed principal ray of the linearly-polari zed image light 1018 , has a first linear polari zation which is aligned with a polari zation transmission axis of the polarisationdependent reflector 1054 . The VPH 1040 spreads , for example fans-out or separates , the linearly-polari zed principal ray of image light 1018 into three di f ferent directions to form three di f ferent linearly-polari zed rays of spread image light which are incident on a second or rear side 1052 of the optical combiner 1050 defined by the polari zation dependent reflector 1054 .

[0073] The first linear polari zation of each of the linearly- polari zed rays of spread image light is aligned with the polari zation transmission axis of the polari zation-dependent reflector 1054 so that the polari zation-dependent reflector 1054 transmits each of the linearly-polari zed rays of spread image light towards the retarder 1056 . The retarder 1056 converts the polari zation of each ray of spread image light from the first linear polari zation to a first circular polari zation . Each ray of spread image light then propagates from the retarder 1056 to the substrate 1060 of the optically-powered reflector 1058 , is transmitted through the substrate 1060 and then reflected at the dichroic reflective coating 1062 of the optically-powered reflector 1058 to form a corresponding ray of first reflected light having a second circular polari zation which is opposite to the first circular polari zation .

[0074] Each ray of first reflected light propagates back through the substrate 1060 of the optically-powered reflector 1058 towards the retarder 1056 . The retarder 1056 converts the polari zation of each ray of first reflected light from the second circular polari zation to a second linear polari zation which is orthogonal to the first linear polari zation and to the polari zation transmission axis of the polari zationdependent reflector 1054 . Accordingly, the polari zationdependent reflector 1054 reflects each ray of first reflected light back towards the retarder 1056 as a corresponding ray of second reflected light .

[0075] The retarder 1056 then converts the polari zation of each ray of second reflected light from the second linear polari zation to the second circular polari zation . Each ray of second reflected light then propagates from the retarder 1056 to the substrate 1060 of the optically-powered reflector 1058 , is transmitted through the substrate 1060 and then reflected at the dichroic reflective coating 1062 of the optically-powered reflector 1058 to form a corresponding ray of third reflected light having the first circular polari zation .

[0076] Each ray of third reflected light propagates back through the substrate 1060 of the optically-powered reflector 1058 towards the retarder 1056 . The retarder 1056 converts the polari zation of each ray of third reflected light from the first circular polari zation to the first linear polari zation which is parallel to the polari zation transmission axis of the polari zation-dependent reflector 1054 . Accordingly, the polari zation-dependent reflector 1054 transmits each ray of third reflected light to form collimated light which travels back through the VPH 1040 as a collimated light R which defines the expanded eye-box 24 .

[0077] The proj ected image light 1018 is spread by the VPH 1040 and then traverses the reflective pancake optical combiner 1050 four times before exiting the reflective pancake optical combiner 1050 on the same side of the reflective pancake optical combiner 1050 as the spread image light entered the reflective pancake optical combiner 1050 from the VPH 1040 .

[0078] As a consequence of the optical power of the optically- powered reflector 1058 , the reflective pancake optical combiner 1050 collimates the spread image light so as to form collimated light which is reflected by the reflective optical combiner 1050 back through the VPH 1040 without the VPH 1040 spreading the collimating light so as to form the collimated light R which propagates to the eye of the user and replicates the image at the eye of the user to thereby expand the eye-box .

[0079] In ef fect , the reflective pancake optical combiner 1050 collimates the spread image light as the spread image light propagates along a folded optical path which is defined within the reflective pancake optical combiner 1050 and which extends from the VPH 1040 and back to the VPH 1040 . As such, use of the reflective pancake optical combiner 1050 serves to reduce the physical thickness of the optical element 10 . Figure 6 shows a first image of an object 30. The object 30 is a human eye. The image comprises a resolution of about 3500x5100 pixels (short: px) . The object 30 comprises 19 different object regions 301. Three object regions 301 are exemplary marked. The object regions 301 marked comprise the shape of rectangles. For example, the projector element 50 can project an image into the optical element 10 which distributes the complete image into each of the object regions 30. In reverse, a detector element 20 looking into the optical element 10 can receive a combined image which contains the superposition of images of each object region 301.

[0080] Figure 7 shows a plurality of object regions 301 of the first image. Each of the 19 object regions 301 can be depicted as a cutout of the first image of the object 30 shown in figure 6. Each cutout has an approximate size of 300x300 pixels.

[0081] Figure 8 shows a combined image from the superposition of the plurality of object regions 301 of the first regions. The superposition of the images of all object regions 301 contains the image information of all object regions 301. From the combined image, a gaze vector of the eye can be computed. The resolution of the combined image is about 300x300 pixels. In particular, the combined image has less than half the resolution as the first image of all object regions 301.

[0082] The invention described herein is not limited by the description given with reference to the exemplary embodiments. Rather, the invention encompasses any novel feature and any combination of features, including in particular any combination of features in the claims, even if this feature or this combination is not itself explicitly indicated in the claims or exemplary embodiments.

[0083] This patent application claims the priority of the German patent application 102023119337.6 and the German patent application 102023125492.8, the disclosure contents of which are hereby incorporated by reference.

[0084] References

[0085] 1 optoelectronic arrangement

[0086] 10 optical element

[0087] 1018 proj ected image light

[0088] 1040 volume phase hologram

[0089] 1050 optical combiner

[0090] 1051 front side

[0091] 1052 rear side

[0092] 1054 polari zation-dependent reflector

[0093] 1056 retarder

[0094] 1058 optically-powered reflector

[0095] 1060 transparent substrate of optically-powered reflector

[0096] 1062 dichroic reflective coating

[0097] 1064 air gap

[0098] 1070 circular polari zer

[0099] 20 detector element

[0100] 201 optical system

[0101] 202 processing unit

[0102] 30 obj ect

[0103] 40 deflector element

[0104] 50 proj ector element

[0105] 301 obj ect region

[0106] 70 infrared light source

[0107] E emission plane

[0108] R collimated light

Claims

Claims1. Optoelectronic arrangement (1) comprising:- an optical element (10) and a detector element (20) , wherein- the optical element (10) is configured to superimpose a plurality of images of different object regions (301) of an object (30) in a combined image,- the optical element (10) is arranged between the object (30) and the detector element (20) along an optical path extending from the object (30) to the detector element (20) , and- the detector element (20) is configured to receive the combined image of the object regions (301) .

2. Optoelectronic arrangement (1) according to the preceding claim further comprising a projector element (50) defining a further optical path extending from the projector element (50) to the object (30) , wherein the optical element (10) is arranged along the further optical path between the projector element (50) and the object (30) .

3. Optoelectronic arrangement (1) according to the preceding claim, wherein- the optical element (10) is configured to distribute a display image generated by the projector element (50) into the different object regions (301) on the object (30) .

4. Optoelectronic arrangement (1) according to the preceding claim, wherein- the optical element (10) is configured to distribute the display image into at least 2, preferably at least 5, andparticularly preferably at least 10 different object regions(301) .

5. Optoelectronic arrangement (1) according to claim 3, wherein- the optical element (10) is configured to distribute the display image into at least 19 different object regions (301) .

6. Optoelectronic arrangement (1) according to one of the preceding claims, wherein- a deflector element (40) is arranged in the optical path between the optical element (10) and the detector element(20) , and configured to deflect light incident from the object (30) to the detector element (20) .

7. Optoelectronic arrangement (1) according to the preceding claims, wherein- the deflector element (40) is a beam splitter.

8. Optoelectronic arrangement (1) according to claim 6, wherein- the deflector element (40) comprises a dichroic mirror.

9. Optoelectronic arrangement (1) according to one of the preceding claims, wherein- the detector element (20) comprises a photodiode array, a CMOS or CCD image sensor.

10. Optoelectronic arrangement (1) according to one of the preceding claims, wherein- the object (30) is a pupil of a human eye.

11. Optoelectronic arrangement (1) according to one of the preceding claims, wherein- an optical system (201) is arranged upstream of the detector element (20) .

12. Optoelectronic arrangement (1) according to one of the preceding claims, wherein- an infrared light source (70) is arranged upstream of the obj ect ( 30 ) .

13. Optoelectronic arrangement (1) according to the preceding claim, wherein- the infrared light source (70) emits electromagnetic radiation in the near infrared wavelength range.

14. Optoelectronic arrangement (1) according to one of the preceding claims 12 and 13, wherein- the infrared light source (70) emits electromagnetic radiation having a coherence length of at most 100 pm.

15. Method for tracking the movement of an object (30) being a human eye using an optoelectronic arrangement (1) according to one of the preceding claims and comprising the steps of:- receiving a first combined image and at least a second combined image, wherein the second combined image is taken subsequently to the first combined image,- computing a movement of the eye based on a comparison of the first and second combined image.

16. Method for tracking the movement of an object (30) being a human eye according to the preceding claim,- wherein the step of computing the movement of the eye isperformed by using an algorithm comprising an artificial intelligence method.

17. Method for tracking the movement of an object (30) being a human eye according to one of the preceding claims, wherein- the step of computing is performed in a processing unit (202) arranged in the detector element (20) .

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