Objective lens arrangement structure, measurement device and method for measuring near-eye devices

Abstract

To provide a measurement device for measuring a near-eye display (NED).SOLUTION: Regarding an objective lens arrangement structure having a front aperture, and objective and liquid lenses, the objective and liquid lenses are fixedly disposed along a light axis in a position in an image-forming side relative to the front aperture, and an image-forming beam path presented to an objective side in a side opposite to the front aperture is set so as to form an image on at least one sensor plane. The liquid lens can adjust an optical effect such that an NED image-forming beam path that can be clearly perceived by a human observer can be clearly formed on at least one sensor plane by adjustment of the liquid lens. The front aperture is designed as an opening diaphragm for a system incidence pupil in an objective lens arrangement structure and has an opening of 2 mm to 6 mm.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention relates to an objective lens arrangement structure having a front aperture, an objective and a liquid lens, the objective and the liquid lens being fixedly positioned along an optical axis at a position on one image side of the front aperture and configured to image onto at least one sensor plane a virtual image presented on the opposite objective side at an image distance in front of the front aperture.

[0002] The invention further relates to a measuring device for measuring a near-eye display (NED) comprising such a lens arrangement and a sensor.

[0003] The invention further relates to a method for the photometric measurement of NED using such a measurement device. [Background technology]

[0004] Near-eye displays (NEDs) (also called near-eye devices) are known from the prior art as devices in which an image is presented at a distance significantly shorter than the reading distance, typically less than 5 centimeters. NEDs are known in the form of glasses (e.g., virtual reality (VR) glasses, augmented reality (AR) glasses) and can be fixed to the viewer's head by glass temples, a frame, and / or a headband. They comprise, for example, a light-emitting diode (LED) display. The image displayed on this display element is presented to the viewer's eye by the internal NED optics as a virtual image at a virtual distance from the eye's pupil plane along the visual axis (on the side of the NED facing away from the viewer).

[0005] The internal NED optics can be focused to display virtual images at various distances. The various focus states of the NED are compensated for by the corresponding various adjustments of the viewer's eyes, so the displayed image always appears clear and sharp.

[0006] Typically, the virtual image is displayed at a distance of at least 20 centimeters from the viewer's eyes (corresponding to the reading distance or near range of the human eye). In the following, a virtual image is understood to be a virtual image presented at such a distance (behind the NED, from the viewer's eyes) in the geometrical ray-optics sense.

[0007] Furthermore, NEDs are known in which an image is projected onto the retina of an observer's eye by a sufficiently steep deflection (e.g., by a micromechanical system with deflectable micromirrors) of a collimated laser beam or similarly collimated beam path from another light source. This imaging method, known as retinal lighting or retinal imaging, can also be used to present an image visible to the observer's eye at a distance that can be arbitrarily varied, for example, by adaptive optics. Such NEDs may require the observer's eye to adjust to a fixed or variable focal length so that the presented image is correctly projected onto the retina.

[0008] In the following, the beam path by which the NED projects an image onto the retina of the observer's eye will generally be referred to as the NED imaging beam path, regardless of whether a virtual image is projected onto the retina or whether it is projected using a sharply deflected collimated beam (as in retinal lighting). In either case, accurate photometric measurements require adjustments of the optics of the measuring device similar to the accommodation of the observer's eye.

[0009] Document US2019 / 0191151A1 describes a system and method for performance characterization of a multi-structure near-eye display, including: a mirror; a lamp; a beam splitter; a collimating reflective lens for collimating light reflected from the beam splitter and reflecting it toward an image sensor having a viewfinder; a field of view (FOV) aperture for projecting light from the lamp through an objective lens onto a device under test (DUT); a video viewfinder digital camera for capturing a virtual image of the DUT; a spectroradiometer for performing spectroradiometry on the captured image of a defined measurement area to characterize the performance of the DUT; and a controller circuit for characterizing the performance of the DUT based on the spectroradiometry.

[0010] Photometric measurements of such NEDs also require a measuring device that is small enough and easy to maneuver so that it can be inserted into structural and movement spaces limited by spectacle temples, frames, and similar holding devices. Furthermore, such a measuring device must be able to simulate the accommodative behavior (changes in the refractive power of the ocular lens) and accommodation behavior (changes in the aperture diameter of the eye's pupil, which acts as the eye's entrance pupil) of the observer's eye. Furthermore, for a correct measurement, the position of the measuring device's entrance pupil must correspond to the position of the eye's entrance pupil (i.e., the eye's pupil).

[0011] Known photometric devices do not meet these requirements or do so inadequately. Therefore, there is a need for improved measurement devices and methods for measuring NED. DISCLOSURE OF THE INVENTION

[0012] According to a first aspect, the invention is based on the problem of realizing a lens arrangement suitable for use in a measuring device for improved photometric measurements of NEDs. This problem is solved according to the invention by an objective lens arrangement having the features of claim 1.

[0013] According to a second aspect, the invention is also based on the problem of providing a measuring device suitable for improved photometric measurements of NEDs. This problem is solved according to the invention by a measuring device having the features of claim 10.

[0014] According to a third aspect, the invention is also based on the problem of providing a method for improved photometric measurement of NEDs, which problem is solved according to the invention by a method having the features of claim 13.

[0015] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0016] A measuring device for photometric measurement, e.g. photometric and / or colorimetric and / or spectroscopic measurement, of a near-eye display (NED) comprises a lens arrangement for imaging an imaging beam path presented by the NED, e.g. an imaging beam path for imaging a virtual image or an imaging beam path set up for retinal lighting, onto a sensor surface of a sensor.

[0017] According to a first aspect of the invention, the objective lens arrangement comprises a front aperture, an objective (which may comprise one or more objective lenses), and a liquid lens whose optical effect, in particular its refractive power, is variable. The objective and the liquid lens are arranged in a fixed position along the optical axis, i.e., immovably along the optical axis, on the image side relative to the front aperture, i.e., on the side of the front aperture facing away from the NED measured by the objective lens arrangement and towards at least one sensor plane. The liquid lens can be designed as part of the objective, in particular structurally connected to the objective, or can be provided independently of the objective.

[0018] The objective and liquid lens are configured and arranged to image the imaging rays emitted from the NED onto at least one sensor plane, with the imaging rays presented on the side of the front aperture opposite the imaging side. This side (facing the NED) is referred to as the object side. Thus, the front aperture is positioned in front of the objective and liquid lens and faces the NED (which provides the imaging beam path) to be measured.

[0019] The optical effect of the liquid lens, in particular its focal length, is adjustable. In particular, the liquid lens is configured to have a change in refractive power similar to the accommodation ability of the human eye of about 10 diopters, so that the imaging beam path presented by the NED for various accommodation states of the observer's eye can be sharply imaged at at least one sensor plane by adjusting the liquid lens.

[0020] The front aperture is designed as an aperture stop for the system entrance pupil of the objective lens arrangement and has an aperture opening in the range of the aperture opening (diameter) of the pupil opening of the human eye that can be changed by accommodation. Preferably, the front aperture has an aperture opening with a diameter between 2 mm and 6 mm.

[0021] The system entrance aperture is the common cross section of all homocentric beam bundles entering the lens arrangement.

[0022] The advantage of this objective lens arrangement is that the entrance pupil formed by the front aperture is externally accessible, which means that it can be positioned very precisely, for example with respect to the NED. Furthermore, it is particularly easy to manipulate, for example by replacing the front aperture with one with a different aperture, and if it is designed as an adjustable diaphragm, the aperture can be easily changed.

[0023] Furthermore, the objective lens arrangement has the advantage that an adjustable, preferably focusable, liquid lens is used to sharply focus the imaging beam path provided by the NED onto at least one sensor plane without requiring mechanical movement of the lens arrangement or components contained therein. This allows for space savings compared to known solutions for focusable lens arrangements that require a range of movement for lenses or lens groups. In particular, this allows for a particularly short length of the lens arrangement in the direction of the optical axis passing perpendicularly through the front aperture.

[0024] Such a lens arrangement can therefore be used to particular advantage in measurement situations where the freedom of movement is limited, for example when imaging a virtual image of a NED onto a sensor used for photometric measurements.

[0025] In a direct projection NED (i.e., by way of retinal lighting, for example, with a laser beam), the internal NED optics typically ensure that the beam of the imaging beam path projected onto the observer's eye is the principal beam that passes through the principal point of the observer's eye, so that a sharp image of the same size is always produced on the retina of the observer's eye, even as the eye accommodates. It is known that the position of the principal point of the observer's eye moves with accommodation.

[0026] In one embodiment of an objective lens arrangement configured for such direct projection NED measurements, the liquid lens is configured and positioned such that the principal point can be positioned by varying its optical power, which allows other potential effects caused by accommodation to be investigated.

[0027] In one embodiment of the lens arrangement structure, the objective and liquid lens are configured to image a virtual image presented on the opposite objective side at an image distance in front of the front aperture onto at least one sensor plane, and the optical effect of the liquid lens is adjustable by adjusting the liquid lens so that a virtual image presented in the focal range can be clearly imaged onto at least one sensor plane.

[0028] In particular, the refractive power of the liquid lens can be adjusted so that a virtual image presented in a focal range that can be sharply imaged onto the retina of an observer's eye (instead of the measurement device) that captures the NED through accommodation can be sharply imaged onto at least one sensor plane. In other words, the liquid lens is set in conjunction with the objective lens to image onto at least one sensor plane a virtual image whose image distance falls within the focal range.

[0029] In one embodiment, the front aperture is designed as an interchangeable diaphragm with a discretely adjustable diaphragm opening or as an iris diaphragm with a continuously adjustable diaphragm opening, which is suitable for measurements with different input apertures, e.g., photometric measurements of NED corresponding to different adaptation states of the observer's eye.

[0030] In one embodiment, the liquid lens is placed on the image side between the front aperture and the objective, which allows the use of a liquid lens whose diameter is smaller compared to the diameter of the downstream objective lens, and therefore can be manufactured more cost-effectively and / or more accurately.

[0031] In one embodiment, the diameter of the liquid lens and objective is 32.5 mm or less. This embodiment can be manufactured at low cost and is sufficient for many measurement purposes, such as photometric measurements of the NED, especially when the lens arrangement is pivoted relative to the NED for successive measurements so that the virtual images presented by the NED are captured at overlapping spatial angles.

[0032] In one embodiment, the lens is configured for an image-side entcentric beam path or an image-side telecentric beam path.

[0033] The entocentric beam path allows the use of sensors with large sensor areas compared to the cross section of the lens arrangement, meaning that relatively large, highly accurate sensors can be used in combination with relatively small, correspondingly inexpensive lenses.

[0034] A telecentric beam path allows the sensor location to vary with distance to the objective arrangement without affecting the image scale and is particularly robust.

[0035] In one embodiment, the objective comprises a first objective group configured to image a virtual image provided by the objective lens arrangement at the input side into an intermediate image in an intermediate image plane, and further comprises at least one structurally separate, preferably independently mounted, second objective group, which is arranged in the beam path downstream of the first objective group and configured to image the intermediate image into at least one sensor plane.

[0036] The structural separation of the objectives means that only a first objective group, which is relatively small compared to the entire objective, can be arranged in the immediate vicinity of the measurement object to be imaged, while at least one downstream second objective group can be arranged at a distance from it. This allows for high optical quality measurements, for example by imaging a virtual image onto the sensor plane with diffraction-limited accuracy, even within limited structural and movement space.

[0037] In a further development of this embodiment, a field lens is arranged in the intermediate image plane, which is configured to align the first exit pupil of the first objective group with the second entrance pupil of the second objective group, i.e. the diameter of the first objective group can be selected to be the same as the diameter of the second objective group, which allows for a particularly space-saving and slim design of the lens arrangement.

[0038] Alternatively or additionally, the field lens can be configured to correct aberrations, for example astigmatism or field curvature, which further improves the optical quality of the image.

[0039] In one embodiment, the objective lens arrangement comprises at least one beam deflector, such as a deflecting mirror or a deflecting prism, which deflects the light rays of at least one optical path at an angle and / or offset relative to a first optical axis passing perpendicularly through the front aperture. This saves installation space in the direction of the first optical axis. This embodiment is therefore particularly suitable for photometric measurements of measurement objects where space for arranging a measuring device in the radial direction of the measurement object is limited, for example, for photometric measurements of NEDs where a glass temple or similar holder protrudes into the space around the visual axis.

[0040] In one embodiment, at least one beam splitter is arranged in the beam path of the objective lens arrangement on the image side after the liquid lens to split the beam path into spatially corresponding images of the virtual image along the first optical path onto the first sensor plane and spatially corresponding images of the virtual image along at least one further optical path onto further sensor planes, thereby enabling, for example, simultaneous, spatially corresponding and spatially resolved measurements of the first luminance camera and the second luminance camera and / or colorimetric camera and / or machine vision camera and / or light field camera and / or spectrometer.

[0041] According to a second aspect, a measuring device for measuring NED comprises an objective arrangement according to the first aspect of the invention and at least one sensor arranged in the sensor plane and configured for photometric and / or colorimetric and / or spectroscopic measurements, respectively. Preferably, the at least one sensor is designed as a spatially resolved planar sensor, but it may also be a point sensor or a sensor measuring integrally over the sensor surface.

[0042] The proposed measuring device is particularly suitable for limited installation space on the imaging side of the NED (e.g., due to a spectacle temple or similar holder). Furthermore, the externally accessible front aperture allows it to be moved particularly easily and precisely to a position corresponding to the pupil position of the observer's eye. This allows particularly accurate measurements of the NED (corresponding to the observer's eye perception). Furthermore, the measuring device can be adapted to various focus states of the NED by adjusting the liquid lens, without changing the position of the system entrance pupil (and therefore the correspondence between the measurement value and the observer's eye perception).

[0043] Further advantages of the measuring device correspond to the advantages of the lens arrangement according to the first aspect of the invention.

[0044] In one embodiment, the measurement device is designed to pivot about a pivot axis that extends perpendicular to a first optical axis that passes perpendicularly through the front aperture and intersects the first optical axis at a distance from the front aperture that is approximately equal to the distance of the pivot point from the pupil of the human eye.

[0045] By rotating the measurement device, different parts of the image presented by the NED can be captured, and the eye's center of rotation and the center of rotation of the rotation (i.e., the intersection of the axis of rotation and the first optical axis) are at the same distance from their respective effective entrance pupils (front aperture or eye pupil / iris), thus maintaining correspondence with the human observer's visual perception.

[0046] The swivel function ensures that the measuring device only captures a partial area (i.e., only a specific spatial angle) of the virtual image on at least one sensor at each swivel position. Nevertheless, successive measurements with overlapping partial areas can be used to analyze the virtual image represented by the measured NED as a whole. This allows the design of particularly slim and space-saving measurement arrangements.

[0047] In one embodiment, an optical filter is arranged in at least one optical path of the measurement device, i.e., between the virtual image emitted by the NED and the at least one sensor. The optical filter has transmission characteristics that match the spectral sensitivity of the entire system, including the objective and sensor of the measurement device, according to a predefined target function. The target function can be determined, for example, by the typical spectral sensitivity of a photopic, scotopic, or circadian observer, or by the effective light spectrum or similar optical effects related to the observer's eye. In an embodiment, the optical filter can be configured as a photometric or colorimetric filter, which allows for particularly accurate and / or specific photometric / radiometric or colorimetric measurements.

[0048] According to a third aspect of the present invention, in a method for photometric measurement of NED using a measurement device according to the second aspect of the present invention, at least one optical disturbance arising in the interaction of the measured NED with the lens arrangement is computationally corrected from at least one raw measurement recorded by at least one sensor. For example, optical disturbances arising as stray light, false light and / or multiple reflections can be computationally corrected (i.e., by a computer-implemented algorithm).

[0049] This allows for the avoidance of suppressing such optical interference by external physical apertures, which are typically used when measuring large area displays but are not applicable to NEDs due to spatial and optical limitations. Computational corrections can, for example, increase the contrast range and thus improve the performance of the measurement device.

[0050] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. [Brief explanation of the drawings]

[0051] [Figure 1] FIG. 1 is a schematic diagram showing a near-eye device (NED) known from the prior art. [Figure 2A] FIG. 2A is a schematic diagram of a measurement device for measuring a near-eye device in various pivot positions. [Figure 2B] FIG. 2B is a schematic diagram of a measurement device for measuring a near-eye device in various pivot positions. [Figure 3A] FIG. 3A is a schematic diagram of the image-side entocentric and telecentric beam paths through the measurement device. [Figure 3B] FIG. 3B is a schematic diagram of the image-side entocentric and telecentric beam paths through the measurement device. [Figure 4] FIG. 4 is a schematic diagram of an objective lens arrangement having collinear objective groups optically separated by an intermediate image plane. [Figure 5] FIG. 5 is a schematic diagram of an objective lens arrangement with a separate objective group and a field lens located at the intermediate image plane. [Figure 6] FIG. 6 is a schematic diagram of an objective lens arrangement with a separate objective group and a deflection mirror located at the intermediate image plane. [Figure 7] FIG. 7 is a schematic diagram of an objective lens arrangement with a separate objective group, a field lens located at the intermediate image plane, and a deflection mirror located in the second objective group. [Figure 8] FIG. 8 is a schematic diagram of a measurement device having a beam path split into two beam paths along two downstream objective groups, each with a full aperture, and two sensors. [Figure 9] FIG. 9 is a schematic diagram of a measurement device having a beam path split into two beams along two downstream objective groups, each with a partial aperture, and two sensors. [Figure 10] FIG. 10 is a schematic diagram of a measurement device with a liquid lens located within the downstream objective group. DETAILED DESCRIPTION OF THE INVENTION

[0052] Corresponding parts are given the same reference numerals in all the figures.

[0053] 1 shows a schematic diagram of a near-eye device (NED) 20, known from the prior art in the form of video or virtual reality (VR) glasses. The NED 20, also known as a near-eye display or head-mounted display, is intended to project images onto the human eye from a distance shorter than the ideal reading distance, typically less than 5 centimeters. The NED 20 typically includes eyeglass temples 22 and / or a headband 23 or similar support frame for attachment to the human head.

[0054] Along a visual axis SA, the viewing eye perceives an image displayed by an internal display element 21 of the schematically depicted NED 20. Such a display element 21 can be designed, for example, as an array (matrix) of light-emitting diodes (LEDs).

[0055] The NED 20 is fixed by a spectacle frame including eyeglass temples 22 and / or a headband 23 so that the pupil of the viewing eye is located at a pupil position PX at a distance s1 from the display element 21 relative to the visual axis SA. Typically, the NED 20 includes internal imaging optics, not shown in detail in Figure 1, for mapping the (real) image displayed on the display element 21 to a typically magnified virtual image V at an image position VX at a virtually magnified image distance s2 (i.e., greater than the actual distance s1 of the display element 21 from the pupil position PX).

[0056] The internal imaging optics of the NED 20 can be designed to be focusable, meaning that the position of the virtual image V (i.e., image position VX at image distance s2 from the pupil position PX) can be changed within a focus range VΔ. Such changes are compensated for by accommodation of the eye (i.e., by changing the refractive power of the eye's lens) so that a sharp image is always formed on the retina of the eye, even in different focus states of the NED 20, and this image appears at a different image distance s2 from the pupil position PX in each state of accommodation.

[0057] The mechanical structure of the NED 20, in particular the very small distance between the display element 21 and the eye pupil at the pupil position PX, makes photometric measurements of the NED 20 more difficult. In particular, the structure and movement space on the image side facing the viewing eye is limited due to the arrangement of the measurement device 100 (not shown in FIG. 1), for example by the headband 23 and / or the glass eye temple 22.

[0058] This limitation makes measuring a focusable NED 20 particularly difficult because the focus state of the measurement device 100 must be adjusted for various positions of the virtual image V in the focus range VΔ. Measuring devices known in the prior art use adjustable optical elements to adjust the focus state along the visual axis SA. However, the range of movement required for this conflicts with the aforementioned structural and movement space limitations.

[0059] Therefore, there is a need for a measurement device 100 that can accommodate limited structural and movement space, yet has high optical quality and measurement accuracy.

[0060] 2A and 2B show a near-eye device (NED) 20 and a measurement device 100 for its optical measurement purely diagrammatically. The measurement device 100 is arranged for measurements, e.g., photometric or colorimetric measurements, at the position where a human visual eye (according to FIG. 1) would be located. In FIG. 2A, the optical measurement axis OA (i.e., the optical axis OA of the measurement device 100) coincides with the visual axis SA of the eye looking at the NED 20, as shown in FIG. 1.

[0061] The measuring device 100 comprises a first sensor 130 arranged in a sensor plane S perpendicular to the optical measurement axis OA, and an objective lens arrangement structure 101, which is configured to image a virtual image V presented by the NED20 onto the sensor plane S.

[0062] For accurate measurements, the system entrance pupil EP of the measurement device 100 must be located at the pupil of the eye for which the NED 20 is intended to be used, i.e., at the same pupil position PX as the pupil of the viewing eye shown in Figure 1. To this end, the measurement device 100 has a front aperture 140, which is located at the pupil position PX along the visual axis SA.

[0063] The beam path emerging from the NED 20 is depicted in a simplified manner using only edge ray bundles B1 and B2.

[0064] NEDs 20 are known in which the images of multiple internal display elements 21 and / or (in the case of augmented reality (AR) glasses) the surrounding image are superimposed. For simplicity, the principle of the proposed measuring device 100 is explained using only one internal display element 21. However, this principle can be transferred to measurements on NEDs 20 with multiple internal display elements 21.

[0065] In the case of a focusable NED 20, the objective lens arrangement 101 must also be able to adapt in an eye-compatible manner to different focus states of the NED 20. The pupil position PX must not be changed when adapting the focus state.

[0066] The design of the NED 20, for example, the design of the NED 20 as VR glasses with eyeglass temples 22 and / or headband 23, limits the installation space and mobility of the measurement device 100. In particular, the objective lens arrangement structure 101 must be designed accordingly to be slim in order to avoid collision with the NED 20.

[0067] For the most accurate measurements possible, the objective lens arrangement 101 should be diffraction limited. If aberrations, such as chromatic aberrations, are unavoidable, the internal optics of the NED 20 should be designed not to compensate for these aberrations, so as not to (actively) falsify the measurement results.

[0068] The objective lens arrangement 101 comprises a liquid lens 110 and an objective 120, which are linearly arranged behind the front aperture 140 along the optical measurement axis OA of the measurement device 100, i.e. aligned with the image side BS pointing away from the NED 20. The objective side OS, which is opposite the image side BS along the optical measurement axis OA, faces towards the NED 20.

[0069] Analogous to the generation of an image on the retina, the objective 120 images the electric field rays from the NED 20 (schematically represented by the edge ray bundles B1, B2) entering the measurement device 100 at various angles onto the two-dimensional sensor 130, where the two-dimensional sensor is positioned in a first sensor plane S perpendicular to the optical measurement axis OA.

[0070] Sensor 130 is designed to spatially resolve photometric and / or colorimetric parameters of NED 20, for example, to measure luminance or to measure parameters of the spectral composition of the light emitted by NED 20.

[0071] At the entrance or object side (i.e., the object side OS opposite the sensor plane S), the objective lens arrangement structure 101 has a front aperture 140, which is arranged in front of all optically active elements of the measurement device 100 and has a circular opening concentric with the optical measurement axis OA, which opening serves as the system entrance pupil EP of the measurement device 100.

[0072] With respect to the NED 20, the front aperture 140 is positioned at the pupil position PX, i.e., at the position where the pupil of a human eye would normally be located if the NED 20 were fixed to a human head (e.g., using eyeglass temples 22 and / or a headband 23 or similar support frame).

[0073] The diameter of the system entrance pupil EP is selected from the range of approximately 2 to 6 millimeters, similar to the pupil diameter of the human eye, and may in particular also be variable.

[0074] The optical effect of the liquid lens 110, in particular its refractive power, can be changed by electrical control, in a manner described in detail below, in particular without mechanically changing its relative position with respect to the objective 120 or its relative position with respect to the measurement device 100.

[0075] By changing the refractive power of the liquid lens 100 (also called a tunable lens), changes in the focus state of the NED 20 can be compensated for in a manner similar to eye accommodation, and a clear image of the virtual image V is always produced on the sensor plane S as long as the virtual image V is displayed within the focus range VΔ of the NED 20.

[0076] Furthermore, the optical effects of the objective 120 can be corrected by modifying the liquid lens 110 .

[0077] Focusing the image of the virtual image V onto the sensor plane S by the liquid lens 110 has the advantage that no optical elements need to be moved, and furthermore, the width of the optical arrangement (i.e., the distance between the objective 120 and the display element 21 of the NED 20 and / or to the sensor 130) does not need to be changed.

[0078] The liquid lens 110 allows for rapid focusing of the image of the virtual image V on the sensor 130. Furthermore, the use of the liquid lens 110 makes it possible to realize a particularly compact measuring device 100, since no mechanically moving optical elements are required, in particular no mechanical movement of the objective 120 or individual parts of the objective 120, i.e. no additional movement space is required for mechanically moving optical elements.

[0079] As a result, good imaging can also be achieved for structures and movement spaces that are typically particularly limited by the mechanical and / or optical constraints of the NED 20 (e.g., by eyeglass temples 22 or headband 23, and for projections intended for very short distances to the eyes). Furthermore, the absence of mechanically moving elements in the measurement device 100 allows for particularly accurate and repeatable measurements of the NED 20.

[0080] The observer can rotate their eyeball to perceive different areas of the image displayed by the NED 20, and as a result, orient their visual axis SA in a direction different from that shown in Figure 1. In a corresponding manner, to be able to measure different points of the object field emitted by the display element 21 of the NED 20, the objective lens arrangement 101 of the measuring device 100, and therewith the sensor 130, must be pivotable relative to the display element 21 about a pivot axis SA with respect to the NED 20. This ensures that the position and arrangement of the system entrance pupil EP relative to the sensor 130 is maintained when the measuring device 100 is rotated, similar to the position and arrangement of the eye pupil relative to the retina when the observer's eye is rotated.

[0081] The pivot axis SX is perpendicular to and passes through the optical measurement axis OA at a distance s3 behind (i.e., toward the image) the system entrance pupil EP formed by the front aperture 140. This distance s3 is approximately equal to the typical distance of the center of rotation from the pupil of the human eye, which can be assumed to be about 10 millimeters within individual variations.

[0082] In the illustration of Figure 2A, the optical measurement axis OA corresponds approximately to the visual axis SA of a viewer's eye aligned perpendicular to the display element 21 of the NED 20, as shown in Figure 1. Figure 2B shows a different arrangement of the NED 20 and measurement device 100, except that the measurement device 100 is pivoted by a pivot angle α about a pivot axis SX, which passes approximately through the pivot point of the viewing eye, as shown in Figure 1.

[0083] By rotating the measurement device 100 relative to the NED 20, it is possible to track changes in the gaze direction and / or changes in the position of the NED 20 relative to the eye. In other words, this makes it possible to measure the image that will be formed on the observer's eye in the same way even when the visual angle of the visual axis SA relative to the NED 20 and / or the position of the NED 20 are changed.

[0084] Furthermore, by pivoting the measuring device 100, the field of view captured by the sensor 130 can be limited, so that the objective 120 can be realized in a compact telescopic arrangement.

[0085] The structure and optical mode of operation of the measuring device 100 will now be explained in further detail with reference to the figures.

[0086] 3A and 3B respectively show schematic beam paths through a measurement device 100 having a liquid lens 110, an objective 120, and an objective arrangement 101 with a front aperture 140 separating the entrance side from the sensor 130. For ease of representation, the pivot axis SX is not depicted in these and the following figures. The courses of the electric field rays entering the objective arrangement 101 through the front aperture 140 at different angles to the optical axis OA are shown by way of example only by ray bundles B1 to B3.

[0087] 3A and 3B, the liquid lens 110 is arranged on the object side of the objective 120, between the objective 120 and the front aperture 140. The objective 120 comprises a plurality of lenses 121 arranged linearly along an optical measurement axis OA. The lenses 121 are designed as circular optics with an objective diameter D. The optically active surfaces of the lenses 121 are preferably spherical for easy and cost-effective manufacture, although some or all of the lenses 121 can also be designed as aspherical to achieve particularly high, in particular diffraction-limited, imaging quality.

[0088] For example, the objective 120 can be mounted in a tube, not shown in Figures 3A and 3B, that allows a free optical path over a lens diameter D of 30 millimeters. The objective 120 thus formed (from a lens 121 or group of lenses with a lens diameter D of approximately 30 millimeters) can be imaged onto the sensor 130 using a liquid lens 110 known from the prior art, capturing a field of view at a spatial angle of approximately 30 degrees.

[0089] On the one hand, this ensures a narrow enough design to avoid mechanical collisions with the NED 20. On the other hand, it allows a wide enough portion of the display element 21 to be measured from a single viewing angle (i.e., without changing the alignment of the measurement device 100 relative to the NED 20).

[0090] To avoid or reduce chromatic aberrations, it is advantageous to combine lens 121 in an assembly that functions as an achromat. Objective 120, optionally together with liquid lens 110, can be mathematically modeled so that artifacts and disturbances, such as stray light, false light, and multiple reflections, that occur within the objective and / or in interaction with the internal optics of display element 21 and NED 20 can be algorithmically corrected. This allows the signal captured by sensor 130 to be optimized for, for example, photometric and / or colorimetric, resolution, contrast, or spectroscopic measurements.

[0091] For example, stray light can be corrected so that the measurable contrast range is algorithmically increased, resulting in improved performance of the objective 120. Such algorithmic (computational) improvement of the image projected onto the sensor 130 is particularly advantageous in the context of the present measurement problem and the proposed measurement device 100, since installation space / mobility limitations do not allow for stray light correction using an external physical aperture, although this is typically possible when, for example, measuring a relatively large display from a relatively large measurement distance.

[0092] By arranging the front aperture 140 on the object side in front of all optically effective elements of the measuring device 100, and thus also in front of all optically effective elements of the lens arrangement 101, different front apertures 140, for example, with different aperture diameters, can be particularly easily exchanged. Alternatively or additionally, the front aperture 140 can be designed as an exchangeable aperture or diaphragm, in which case different apertures (apertures of different sizes) can be placed in the light path as desired. It is also possible to design the front aperture 140 as an iris diaphragm with a variable, in particular continuously adjustable, diaphragm diameter. Such an iris diaphragm can be particularly advantageously motorized.

[0093] This allows measurements of NED20 that correspond to different eye conditions (for example, scotopic vision with a wide pupil of 5-6 mm, or photopic vision with a narrow pupil of 1-2 mm).

[0094] 3A and 3B, the liquid lens 110 is arranged between the front aperture 140 and the objective 120. As a result, a particularly cheap and simple liquid lens 110 can be used, which has a diameter smaller than the objective diameter D. However, it is also possible to arrange the liquid lens 110 at a different position along the optical axis OA, for example within the objective 120, by appropriately adapting the lens arrangement within the objective 120. Such an arrangement will be explained in more detail later with reference to FIG.

[0095] The liquid lens 110 can be designed as an electrically controllable lens, whose refractive power can be changed via an applied electrical voltage (voltage-controlled liquid lens 110) or current (current-controlled liquid lens 110). Voltage-controlled liquid lenses 110 are known and are available, for example, from Corning Incorporated in an embodiment designated A-58N. Current-controlled liquid lenses 110 are known and are available, for example, from Optotune Incorporated in an embodiment designated EL-10-30-TC.

[0096] Liquid lenses 110 whose refractive power is changed by manual mechanical manipulation are also known and may be used.

[0097] According to the embodiment, the change in the optical power of the liquid lens 110 can be controlled manually mechanically, manually electronically, or by an autofocus algorithm. The optical power of an electronically adjustable liquid lens 110 can be changed very quickly, typically within a few milliseconds.

[0098] In one embodiment, the optical effect of the liquid lens 110 may be modified beyond changing its focal length so as to be able to correct high-order aberrations of the objective 120. In a particularly advantageous manner, the objective 120 can be designed to be particularly simple and compact. Aberrations of the simple objective 120 can then be compensated for by such a liquid lens 110. As a result, the optical performance of the entire objective lens arrangement 101 can be further improved.

[0099] 3A, multiple lenses 121 are designed and arranged to generate an image-side entocentric beam path. This embodiment has the advantage that the image scale can be changed by shifting the sensor plane S along the optical measurement axis OA. In particular, the image size on the sensor 130 can be increased by a shift in the direction of the image side BS. In this way, optimized images can be generated for different sizes of sensor 130 (e.g., different sizes of complementary metal-oxide semiconductor (CMOS) or charge-coupled device (CCD) pixel matrices).

[0100] In particular, images can be generated even for sensors 130 having a tip area that exceeds the lens diameter D of the objective 120. As a result, for the reasons explained above, particularly large, high-resolution sensors 130 can be used for measuring devices 100 where the size of the objective 120 is limited, which allows particularly accurate measurements in terms of spatial resolution.

[0101] In the embodiment according to Fig. 3B, the lenses 121 are designed and arranged in such a way that a telecentric beam path is generated on the image side. This embodiment has the advantage that the image scale of the projection onto the sensor 130 remains the same regardless of its position along the optical measurement axis OA. Such an embodiment is therefore particularly robust with respect to tolerances and deviations in the positioning or mounting of the sensor 130 relative to the objective 120.

[0102] 4 shows a schematic representation of an embodiment of the objective arrangement 101, in which the objective 120 is divided into a first objective group 122 (located on the object side) and a second objective group 123 (located on the image side), which can be structurally separated (e.g., mounted on independent mounts). The first objective group 122 generates an intermediate image in an intermediate image plane Z, which is perpendicular to the optical measurement axis OA between the objective groups 122, 123. The second objective group 123 maps this intermediate image onto a first sensor plane S.

[0103] By separating the objective 120, it is also possible to structurally separate the objective lens arrangement 101 and the measurement device 100 such that only a smaller assembly comprising the first objective group 122, the liquid lens 110 and the front aperture 140 (compared to a monolithic design of the lens arrangement 101) needs to be placed in the immediate vicinity of the NED 20, while the second objective group 123 can be placed offset therefrom. This allows the second objective group 123 to be relatively larger than in a monolithic embodiment (i.e. a monolithic embodiment in which the entire objective 120 is mounted in a single mechanical unit such as a tube) without violating the mechanical and / or optical constraints imposed by the design of the NED 20.

[0104] An enlarged sensor 130 can also be used by extending the optical path beyond the space enclosed by the NED 20 and its holding device, thereby improving spatial resolution and / or measurement sensitivity.

[0105] Furthermore, the second objective group 123 may further comprise an additional lens 121 for correcting aberrations. For example, the first objective group 122 may be designed to have no first-order refractive errors but high-order refractive errors (e.g., astigmatism and coma), and thus be simple and compact. The downstream second objective group 123 can be designed to correct high-order refractive errors and / or improve the correction of chromatic aberrations. As a result, the overall quality of the image on the sensor 130, and therefore the accuracy of the measurement, can be improved while taking into account the limited direct installation space on the NED 20.

[0106] The second objective group 123 can be realized as a telecentric arrangement. It can be realized telecentrically or entocentrically on both the object side and the image side. Preferably, the second objective group 123 is aligned with the first objective group 122 and the liquid lens 110 to minimize aberrations.

[0107] The embodiment shown in Figure 4 having two objective groups 122, 123 has the limitation that the electric field rays emerging from the first objective group 122 that intersect at the intermediate image plane Z (i.e., the electric field rays that image the light emitting points of the display elements 21 of the NED 20 onto the intermediate image plane Z) diverge on the imaging side after the intermediate image plane Z and therefore enter the second objective group 123 as a complete bundle of rays B1 to B3 only if the first exit pupil AP1 (not explicitly shown in Figure 4) of the first objective group 122 is the same size as the second entrance pupil EP2 (not explicitly shown in Figure 4) of the second objective group 123.

[0108] For efficient use of the installation space of the measuring device 100, it is advantageous to match the sizes of the first exit pupil AP1 and the second entrance pupil EP2 to one another, in particular to make them identical, and for this purpose the first and second objective groups 122, 123 can be adapted to one another.

[0109] In contrast, the embodiment shown in Fig. 5 further comprises a field lens 124 arranged in or close to the intermediate image plane Z. The field lens 124 maps a first exit pupil AP1 of the first objective group 122 onto a second entrance pupil EP2 of the second objective group 123. In Fig. 5, the first exit pupil AP1 of the first objective group 122 is shown schematically and purely by way of example at an exit pupil position AX, and the second entrance pupil EP2 of the second objective group 123 is shown schematically and purely by way of example at an entrance pupil position EX.

[0110] The field lens 124 allows the pupils AP1, EP2 of objective groups 122, 123 of different sizes (but especially also of objective groups of the same size) to be imaged onto one another, so that, for example, the lens diameters D1, D2 of the first and second objective groups 122, 123 can be selected to be the same size, which saves installation space and allows the objective 120 to be realized with a single, fully utilized lens diameter D1, D2 corresponding to the object field to be imaged.

[0111] Additionally or alternatively, the distance (along the optical axis OA) between the objective groups 122, 123 can be varied, as shown by way of example schematically in Fig. 5 as the distance between the pupils AP1, EP2. This allows for more flexible design of the objective groups 122, 123. In particular, since the entrance pupil EP2 of the second objective group 123 is not subject to the installation space constraints imposed by the NED 20, it is also possible to design the second objective group 123 with improved optical quality.

[0112] The field lens 124 may have further optical effects beyond imaging of the pupils AP1, EP2, and may for example be designed for the correction of astigmatism, field curvature and / or other aberrations, preferably higher-order aberrations, while the first objective group 122 may be simply designed to only avoid or minimize lower-order aberrations (e.g. spherical aberration). In this way, the installation space required for the first objective group 122 can remain small and the overall optical quality of the objective lens arrangement 101 can be improved.

[0113] The beam path shown in Figure 5 is entocentric (on the image side), but telecentric beam paths can also be realized.

[0114] 6 shows a schematic diagram of a further development of the objective arrangement 101 of the measuring device 100 with an objective 120 separated into two objective groups 122, 123, in which a beam deflector 125, designed as a deflection mirror 125, is arranged at the intermediate image position ZX. Preferably, the deflection mirror 125 is inclined at an angle of 45 degrees to the optical measurement axis OA of the first objective group 122 and to the optical measurement axis OA' of the second objective group 123, in other words, the optical axes OA, OA' of the first and second objective groups 122, 123 are perpendicular to each other, and the optical axis OA of the first objective group 122 substantially corresponds to the visual axis SA of the observer's eye, along which the observer perceives the image projected by the measured NED 20.

[0115] An advantage of this further development is that the first objective group 122 can be designed to be small, so that only little installation space is required along the visual axis SA of the NED 20. This also makes it possible to measure NEDs 20 that have particularly narrow limitations along the visual axis SA, for example if such NEDs 20 are equipped with a headband 23 or a support frame that projects onto the visual axis SA at a small distance from the display element 21.

[0116] Instead of the deflection mirror 125, a deflection prism (reflecting prism) can also be used as the beam deflector 125.

[0117] The beam path shown in Figure 6 is entocentric (on the image side), but telecentric beam paths are also possible.

[0118] 7 shows an alternative embodiment of a beam path deflected by a deflection mirror 125. Here, the deflection mirror 125 is not located at the intermediate image position ZX (i.e., on the object side in front of the second objective group 123), but inside the second objective group 123. The resulting arrangement of the field lens 124 at the intermediate image position ZX can achieve the advantages of the beam path bent (deflected) by the deflection mirror 125 described with reference to FIG. 6 as well as the advantages of the field lens 124 already described with reference to FIG. 5.

[0119] FIG. 8 shows a schematic representation of a beam path in the objective lens arrangement 101 of the measuring device 100, which is split by a beam splitter 126 into two mutually perpendicular partial beam paths.

[0120] The second objective group 123 images the intermediate image Z onto the first sensor plane S and is arranged along a first optical path P1 on the imaging side of the beam splitter 126. An additional second objective group 123' images the intermediate image Z onto the second sensor plane S' and is arranged along a second optical path P2 on the imaging side of the beam splitter 126. The first optical path P1 is along a first optical measurement axis OA that is collinear with the visual axis SA. The second optical path P2 is along a second optical measurement axis OA' that is orthogonal to the first optical measurement axis OA / visual axis SA. In the embodiment shown in FIG. 8, the beam path emerging from the first objective group 122 is split into first and second optical paths P1, P2 across the entire aperture (i.e., for all ray bundles B1-B3 emerging from the first objective group 122).

[0121] The beam splitter 126 arranged at the intermediate image position ZX can be designed, for example, as a partially transmitting deflecting mirror 125 or as a partially reflecting deflecting prism.

[0122] By splitting the optical path, one sensor 130, 130' can be placed at each of the two sensor planes S, S'. Therefore, the sensors 130, 130' can perform measurements independently of each other. For example, the first sensor 130 placed at the imaging end of the first optical path P1 can be designed as a luminance measurement camera. The second sensor 130' placed at the imaging end of the second optical path P2 can be designed as a color measurement camera, a light field camera, a machine vision camera, or a spectrometer.

[0123] Therefore, the embodiment shown in FIG. 8 has the advantage that multiple different measurements can be performed synchronously on one NED 20.

[0124] The placement of the beam splitter 126 at the intermediate image position ZX allows a simple geometric correspondence of the images captured by the sensors 130, 130' to each other and to the object (i.e., to the display element 21 of the NED 20). As a result, if one of the sensors 130, 130' is designed as a spectrometer, a locally determined spectral measurement can be performed in parallel with the luminance measurement performed by the other sensor 130, 130'.

[0125] However, it is also possible to position the beam splitter 126 at a different position on the imaging side of the intermediate image position ZX, for example behind one or more lenses 121 of the second objective group 123, thereby allowing the field lens 124 to be positioned at the intermediate image position ZX, with the advantages already described.

[0126] Figure 9 shows an embodiment of a measuring device 100 with an objective lens arrangement 101 having a split beam path similar to that of Figure 8. In contrast to Figure 8, the beam splitter 126 here acts only on a part of the exit aperture AP of the first objective group 122. In other words, only a part, and not all, of the ray bundles B1-B3 are split off along the first optical path P1 onto the first sensor 130.

[0127] The first to third bundles of rays B1 to B3 are deflected along the second optical path P2 to the second sensor 130', which are shown, by way of example only, schematically in Figure 9. From these, it can be seen that only the central bundle of rays B1 of the rays B1, which is focused at the intersection of the first optical axis OA and the intermediate image plane Z, is partially guided to the first sensor 130 via the first optical path P1 in addition to the second optical path P2.

[0128] Such a beam path flow can be achieved with a beam splitter 126 designed, for example, as a hole mirror 127 or as a partially mirrored deflecting mirror 125 (i.e., a mirror that is totally reflective over only a portion of its area).

[0129] Figure 10 shows a further embodiment with two objective groups 122, 123 and a bent (deflected) but unsplit beam path, similar to the embodiment shown in Figures 4 and 5. In contrast to those embodiments already described, in this embodiment the liquid lens 110 is not arranged between the front aperture 140 and the objective 120, but is arranged inside the objective 120 in the second objective group 123. The advantage of this arrangement is that the installation space requirements for the second objective group 123 are reduced compared to an arrangement between the first objective group 122 (located close to the NED 20) and the front aperture 140.

[0130] 10 also comprises an optical filter 150, which is arranged on the object side directly in front of the sensor plane S, although it can also be inserted into the beam path at other points. The optical filter 150 can be designed as a colorimetric or photometric filter, for example, to enable colorimetric or photometric measurements by the sensor 130.

[0131] In embodiments with split beam paths (e.g. according to Figure 8 or Figure 9), multiple optical filters 150 of the same or different designs can likewise be used, one of which is placed in each optical path P1, P2. [Explanation of symbols]

[0132] 20 Near Eye Device (NED) 21 Display element 22 Eyeglass Temple 23 Headband 100 Measuring Devices 101 Objective lens arrangement structure 110 Liquid lens, lens 120 Objective 121 Lens 122 First Objective Group 123, 123' Second Objective Group 124 Field Lens, Lens 125 Deflecting mirrors, beam deflectors 126 Beam Splitter 127 Hall Mirror 130, 130' First and second sensors 140 front aperture 150 filters (photometric, colorimetric) AP1 1st exit pupil, pupil AX exit pupil position B1, B2, B3 First to third ray bundles BS imaging side D1, D2 First and second lens diameters, diameter EP system entrance pupil EP2 2nd entrance pupil, pupil EX Entrance pupil position OA, OA’ First and second optical measurement axes, optical axis OS Object side P1, P2 First and second optical paths (beam paths) PX Pupil position S, S’ First and second sensor planes s1, s3 Distances s2 Image distance, distance SA Visual axis, optical axis SV Swivel axis V Virtual image VX Image position VΔ Focus range Z Intermediate image plane ZX Intermediate image position α Swivel angle

Claims

1. An objective lens arrangement (101), a front aperture (140), an objective (120) and a liquid lens (110); the objective (120) and the liquid lens (110) are fixedly arranged along an optical axis (OA, OA') at a position on the image side (BS) of the front aperture (140) and are designed to image a non-optical imaging beam path onto at least one sensor plane (S, S') when the non-optical imaging beam path is presented on the object side (OS) opposite the front aperture (140); the liquid lens (110) is capable of adjusting an optical effect of the liquid lens, such that an NED imaging beam path that can be clearly perceived by a human observer can be clearly imaged onto the at least one sensor plane (S, S') by adjusting the liquid lens (110); the front aperture (140) is designed as an aperture stop for the system entrance pupil (EP) of the objective lens arrangement (101) and has an aperture opening of 2 to 6 millimeters; The objective (120) is a first objective group (122) for forming a virtual image (V) presented on the opposite object side (OS) at an image distance (s2) in front of the front aperture (140) on an intermediate image plane (Z) to form an intermediate image; and at least one second objective group (123) arranged structurally separated from the first objective group (122) and downstream along the beam path for imaging the intermediate image onto the at least one sensor plane (S, S'), An objective lens arrangement (101).

2. the objective (120) and the liquid lens (110) are designed to image the virtual image (V) onto at least one sensor plane (S, S'); the liquid lens (110) is capable of adjusting its optical effect so that a virtual image (V) presented within a focal range (VΔ) can be sharply focused on the at least one sensor plane (S, S′) by adjusting the liquid lens (110); 2. The objective lens arrangement (101) according to claim 1.

3. the front aperture (140) is designed as an interchangeable diaphragm with a discretely adjustable diaphragm opening or as an iris diaphragm with a continuously adjustable diaphragm opening; An objective lens arrangement (101) according to claim 1 or claim 2.

4. The liquid lens (110) is disposed on the image side between the front aperture (140) and the objective (120).

2. The objective lens arrangement (101) according to claim 1.

5. The liquid lens (110) and the objective (120) have a diameter (D) of at most 32.5 millimeters.

2. The objective lens arrangement (101) according to claim 1.

6. The objective (120) is configured for an image-side entcentric beam path or an image-side telecentric beam path.

2. The objective lens arrangement (101) according to claim 1.

7. a field lens (124) is arranged in the intermediate image plane (Z), the field lens (124) being configured to match a first exit pupil (AP1) of the first objective group (122) with a second entrance pupil (EP2) of the second objective group (123) and / or to correct aberrations; 2. The objective lens arrangement (101) according to claim 1.

8. by at least one beam deflector (125), the beam path of at least one optical path (P1, P2) is deflected at least partially in an oblique and / or offset manner with respect to a first optical axis (OA) extending perpendicularly through the front aperture (140); 2. The objective lens arrangement (101) according to claim 1.

9. at least one beam splitter (126) is arranged in the beam path on the imaging side and after the liquid lens (110) to split the beam path into a spatially corresponding image of the virtual image (V) along a first optical path (P1) onto a first sensor plane (S) and a spatially corresponding image of the virtual image (V) along at least one further optical path (P2) onto a further sensor plane (S'); 2. The objective lens arrangement (101) according to claim 1.

10. A measuring device (100) for measuring a near-eye device (NED) (20), comprising: an objective lens arrangement (101) comprising a front aperture (140), an objective (120) and a liquid lens (110); the objective (120) and the liquid lens (110) are fixedly arranged along an optical axis (OA, OA') at a position on the image side (BS) of the front aperture (140) and are designed to image a non-optical imaging beam path onto at least one sensor plane (S, S') when the non-optical imaging beam path is presented on the object side (OS) opposite the front aperture (140); the liquid lens (110) is capable of adjusting an optical effect of the liquid lens, such that an NED imaging beam path that can be clearly perceived by a human observer can be clearly imaged onto the at least one sensor plane (S, S') by adjusting the liquid lens (110); the front aperture (140) is designed as an aperture stop for the system entrance pupil (EP) of the objective lens arrangement (101) and has an aperture opening of 2 to 6 millimeters; The measuring device further comprises: at least one sensor (130, 130') arranged in a sensor plane (S, S') and designed for photometric and / or colorimetric and / or spectroscopic measurements of said NED (20), a photometric or colorimetric filter (150) is arranged in at least one optical path (P1, P2) leading from a virtual image (V) presented on the opposite object side (OS) at an image distance (s2) in front of the front aperture (140) to the at least one sensor (130, 130'); A measuring device (100).

11. The measuring device (100) a first optical axis (OA) extending perpendicularly through the front aperture (140) and a pivot axis (SX) intersecting the first optical axis (OA) at a distance (s3) from the front aperture (140) toward the image side, the distance (s3) being approximately equal to a typical distance of a pivot point of a human eye from the pupil of the eye; The measuring device (100) of claim 10.

12. a first objective lens arrangement (101) arranged and configured to image a first imaging beam path of the binocular NED (20) onto at least one sensor (130, 130') arranged in the sensor plane (S, S') and configured for photometric and / or colorimetric and / or spectroscopic measurements of the binocular NED (20); A second objective lens arrangement (101) is arranged in the sensor plane (S, S') and arranged and configured to image a second imaging beam path of the binocular NED (20) onto at least one sensor (130, 130') configured for photometric and / or colorimetric and / or spectroscopic measurements of the ophthalmic NED (20), A measuring device (100) according to claim 10 or claim 11.

13. A method for photometric measurement of a NED (20) using a measurement device (100), comprising: The measuring device (100) comprises an objective lens arrangement (101), the objective lens arrangement (101) comprising a front aperture (140), an objective (120), and a liquid lens (110); the objective (120) and the liquid lens (110) are fixedly arranged along an optical axis (OA, OA') at a position on the image side (BS) relative to the front aperture (140), and are designed to image a NED imaging beam path onto at least one sensor plane (S, S') when the NED imaging beam path is presented on the object side (OS) opposite the front aperture (140); the liquid lens (110) is capable of adjusting an optical effect of the liquid lens, such that an NED imaging beam path that can be clearly perceived by a human observer can be clearly imaged onto the at least one sensor plane (S, S') by adjusting the liquid lens (110); the front aperture (140) is designed as an aperture stop for the system entrance pupil (EP) of the objective lens arrangement (101) and has an aperture opening of 2 to 6 millimeters; the measuring device further comprises at least one sensor (130, 130') arranged in a sensor plane (S, S') and configured for photometric and / or colorimetric and / or spectroscopic measurements of the NED (20); At least one optical disturbance occurring in the interaction between the NED (20) and the objective lens arrangement (101) is corrected by calculation from at least one raw measurement recorded by the at least one sensor (130, 130'). method.

Images