Gaze target and centering device

Abstract

The utility model relates to a target watching and centering device. The gaze target is a gaze target (70) for generating a light field for aligning a gaze direction of the eyewear wearer (30) when the eyewear wearer (30) is measured by the centering device (10). During operation, the electromagnetic beam of the generated light field is optically shaped by means of a transparent lenticular body (60). During operation, the electromagnetic beam of the generated light field exits from the optical radiating surface of the lens body (60) in the radiation direction (A). A rear surface (62) of the lens body (60) is formed on a rear surface of the lens body (60) facing away from the radiating surface (61). In this case, the transparent lens body (60) extends from the radiating surface (61) to the rear surface (62) in a direction opposite the radiating direction (A), and in this case at least to the focal plane of the lens body (60).

Description

Technical Field

[0001] The utility model relates to a fixation target, a centering device, a use of a fixation target, and a method. Background Art

[0002] By introducing individually optimized spectacle lenses, the requirements of wearers with various visual defects can be met. For example, lenses with individually optimized fields of view can be provided. Individually adapted spectacle lenses can optimally correct the optical visual defects of the users of the spectacle lenses. For sports glasses, the spectacle lenses can also be calculated and adapted individually. Sports glasses are characterized by large deflections, large face curves of the lens rims, and large rake angles.

[0003] In order to make full use of the optical advantages of personal spectacle lenses, especially individually adapted progressive lenses, these spectacle lenses need to be calculated and manufactured with knowledge of the user's usage position and worn according to the usage position for calculation and manufacture. The usage position depends on a large number of optical centering parameters, such as the user's pupil distance, the face curve of the lens rim, the rake angle of the spectacle lens, the spectacle frame, the corneal vertex distance of the system composed of the glasses and the eyes, and the grinding height of the spectacle lens. These parameters and other parameters that can be used to describe the usage position or other parameters necessary to describe the usage position are included in relevant standards, such as DIN EN ISO 13666, DIN 58 208, DIN EN ISO 8624, and DIN 5340, and the above parameters can be obtained from these standards.

[0004] Here, the spectacle lens can be arranged or centered in the spectacle frame according to the optical centering parameters used during manufacturing, so that the spectacle lens is actually worn by the spectacle wearer at the usage position according to the optical centering parameters.

[0005] In order to determine the individual optical centering parameters, an optician can use various measuring devices, especially a centering device. For example, such a centering device is known from DE 10 2005 003 699 A1. In this case, image data of the head of the spectacle wearer is generated from at least two image acquisition directions, and the optical centering parameters are determined based on these image data. In this case, for example, the line of sight of the spectacle wearer at the usage position can be determined by fixing the bridge of the nose of the test subject in a mirror. A speckle pattern or luminous points can also be used. The goal is to align the line of sight of the spectacle wearer so that the actual alignment of the eyes is consistent with the fixation behavior to be measured.

[0006] A fixation target is known from DE 10 2008 003 906 B4 as an auxiliary device for aligning the line of sight direction of a spectacle wearer for such a centering device. Here, the fixation target generates a light field for controlling the line of sight of the spectacle wearer, and the centering device generates image data of the spectacle wearer's head. This is particularly helpful for visually impaired patients who are unable to perform common visual tasks (e.g., due to high visual impairment and / or strabismus).

[0007] In technical optics, adjustable elements (e.g., lens mounts) are used as fixation targets, and through these adjustable elements, the entire system can be adjusted so that the optical system meets the desired requirements. In this case, in particular, high-precision (and thus expensive) individual elements such as lenses, lens barrels, apertures, etc. can be used to align the light field of the fixation target.

[0008] As an alternative (or additional option) to using such high-precision individual elements, previously known fixation targets require at least one complex opto-mechanical system that has individual elements (e.g., micrometer screw gauges) only for adjusting the fixation target. In order to precisely align the light field generated by the fixation target, in this case, complex manual adjustment of the entire system is required, which is time-consuming and costly.

[0009] Therefore, previously known fixation targets are very costly because their individual components must be designed with high precision and / or must be subjected to complex adjustment. Especially in the lenses of the fixation target, the necessary precision regarding focal length, lateral position of the center, and / or wedge error cannot be achieved by low-cost manufacturing processes. Summary of the Utility Model

[0010] The object of the present utility model is to implement a cost-effective fixation target for a centering device.

[0011] Before introducing the present utility model in detail below, some terms that are helpful for understanding the present utility model are defined or explained.

[0012] For example, spectacle lenses are single-vision lenses, multifocal lenses (e.g., progressive lenses) with or without coloring, mirror coatings, and / or polarizing filters.

[0013] For example, the two "image acquisition devices" are two digital cameras placed separately from each other. Preferably, the image acquisition device may include a digital camera and at least one optical deflection element or deflection mirror, wherein image data of a partial region of the head is recorded or generated by the camera with the aid of the deflection mirror. Accordingly, the two image acquisition devices in the same manner include, for example, two cameras, particularly digital cameras, and at least two deflection elements and / or deflection mirrors, wherein one digital camera and at least one deflection mirror represent one image acquisition device. Additionally, preferably, the two image acquisition devices may also consist of exactly one digital camera and two deflection elements and / or deflection mirrors, wherein the image data is recorded and / or generated by the digital camera in a time-delayed manner. For example, image data of a partial region of the head imaged by one deflection mirror is generated at a first time point, and image data of the partial region of the head imaged by the other deflection mirror is generated at a second time point. Additionally, the camera may also be arranged such that image data is generated by the camera at the first and / or second time point without a deflection mirror, and / or no deflection mirror is arranged between the camera and the head. The two image acquisition devices may generate image data in different acquisition directions.

[0014] Two different and / or distinct "acquisition directions" shall be understood as generating different image data from overlapping partial regions of the head, preferably from the same partial region of the head, particularly, image data and / or comparison image data are generated from the same partial region of the user's head at different viewing angles. Accordingly, although the same partial region of the head is imaged, the image data and / or comparison image data are different. Different acquisition directions may also be achieved, for example, by generating image data from at least two image acquisition devices, wherein the effective optical axes of the at least two image acquisition devices are not parallel.

[0015] The dimensioning in the box size (Kastenmaβ) shall be understood as the measurement system described in the relevant standards, such as DIN EN ISO 8624 and / or DIN EN ISO 13666 and / or DIN 58 208 and / or DIN 5340. Additionally, regarding the box size and other common terms and parameters, reference may be made to the book "Die Optik des Auges und der Sehhilfen (Optics of the Eye and Visual Aids)" by Dr. Roland Enders, 1995, Optische GmbH, Heidelberg, and the book "Optik und Technik der Brille (Optics and Technology of Glasses)" by Heinz Diepes and Ralf Blendowske, 2002, Optische GmbH Publishing House, Heidelberg. Reference can also be made to the brochure "inform fachberatung für die augenoptik (Optician's Expert Advice)", the ZVA's PR series of publications for opticians, Volume 9, "Brillenzentrierung (Glasses Centering)", ISBN 3-922269-23-0, 1998, where, in particular, the box dimensions are schematically shown in Figure 5 and Figure 6 . Reference can also be made to the book "Brillenanpassung Ein Schulbuch und Leitfaden (Glasses Fitting Textbook and Guide)" by Wolfgang Schulz and Johannes Eber, 1997, published by DOZ Publishing House, edited by the Zentralverband der Augenoptiker, Düsseldorf, ISBN 3-922269-21-4, with particular reference to points 1.3, 1.4, and 1.5 and the related illustrations. In this regard, the said standards, manuals, and books form part of the definition of the terms disclosed in this application.

[0016] "Pupil distance" basically corresponds to the distance between the centers of the pupils, especially the distance between the centers of the pupils in the zero line of sight direction (Nullblickrichtung).

[0017] The center of rotation of the eye is the point where the eye remains substantially stationary when the eye moves and the head position is fixed, for example, when the line of sight is lowered or raised by rotating the eye. Thus, the center of rotation of the eye is essentially the center of rotation of the eye.

[0018] The effective optical axis of the image acquisition device is the region of a line that starts from the center of the corresponding aperture of the image acquisition device, is perpendicular to the aperture, and intersects the imaging part region of the user's head. In other words, the effective optical axis is, in particular, the optical axis of the image acquisition device, where these optical axes are typically arranged perpendicular to the lens system of the image acquisition device and start from the center of the lens system. If there are no other optical elements (e.g., deflecting mirrors or prisms) in the beam path of the image acquisition device, the effective optical axis basically corresponds to the optical axis of the image acquisition device. However, if other optical elements (e.g., one or more deflecting mirrors) are arranged in the beam path of the image acquisition device, the effective optical axis no longer corresponds to the optical axis of the image acquisition device starting from the image acquisition device.

[0019] In other words, the effective optical axis is the region of the optical axis of the image acquisition device that may be optically deflected multiple times and that intersects the user's head without changing direction. The optical axis of the image acquisition device corresponds to the line starting from the aperture center of the image acquisition device and perpendicular to the plane including the aperture of the image acquisition device, wherein the direction of the optical axis of the image acquisition device can be changed by optical elements such as plane mirrors and / or prisms. The effective optical axes of two image acquisition devices can almost intersect.

[0020] A "cylindrical lens" is a lens whose curved surface is at least partially designed as at least a part of a cylindrical surface or a part similar to a cylindrical surface. Different from a spherical lens that focuses light to a single point, a cylindrical lens focuses a light beam along a single axis (i.e., the "focal axis" and / or "focal line"). Mathematically, in only one plane, a cylindrical lens can be described as equivalent to a spherical lens. A cylindrical lens can also be designed as a non-cylindrical or aspherical cylinder, i.e., a lens with a cylinder whose cross-section deviates from a circle. A plano-concave and plano-convex non-cylinder can be used in the same way as a non-cylinder with a spherical or aspherical back surface. Such an aspherical cylindrical lens can focus incident light along the focal line without being affected by spherical aberration.

[0021] The "optical axis" of a fixation target having a cylindrical lens is the axis parallel to the direction of the electromagnetic beam generated in the focal line, and these electromagnetic beams are parallel after passing through the cylindrical lens (also see Figure 3 the propagation direction of the parallel light beam 50 shown).

[0022] The term "substantially parallel" describes electromagnetic beams whose propagation directions are particularly parallel. This means that if the propagation directions of two electromagnetic beams are the same, they are parallel. This is especially the case for electromagnetic beams after passing through a cylindrical lens when the electromagnetic beam source is arranged in a focal plane substantially parallel to the focal line of the cylindrical lens, particularly arranged in the focal line of the cylindrical lens. If the electromagnetic beam source is arranged on the focal line, the beam is also perpendicular to the lens plane.

[0023] If the propagation directions of two electromagnetic beams form an angle with each other, the two electromagnetic beams can also be substantially parallel, where the angle is less than about 10°, further preferably less than about 5°, particularly preferably less than about 2°, particularly preferably less than about 1°, particularly preferably less than about 0.25°, particularly preferably less than about 0.1°, very particularly preferably less than about 0.05°. If two electromagnetic beams pass through the focal line of a cylindrical lens and the two electromagnetic beams are perpendicular to the focal line, the two electromagnetic beams are substantially parallel after passing through the cylindrical lens. If only one of the light beams passes through the focal line while the other light beam does not pass through the focal line or neither of the two light beams passes through the focal line, and the two light beams are perpendicular to the focal line, the two light beams are substantially parallel after passing through the cylindrical lens when the corresponding distance from the focal line is less than a predetermined value. For example, this can be achieved by arranging the light source not on the focal line but at a distance from the focal line. Preferably, the distance between the light source and the focal line (or focal plane) is less than about 5% of the focal length of the cylindrical lens, preferably less than about 2% of the focal length of the cylindrical lens, preferably less than about 1% of the focal length of the cylindrical lens, preferably less than about 0.5% of the focal length of the cylindrical lens, preferably less than about 0.1% of the focal length of the cylindrical lens. Therefore, in order to determine the pupillary distance, the device can advantageously achieve a measurement accuracy of at least about ±0.2 mm, preferably at least about ±0.05 mm, further preferably at least about ±0.01 mm. For a Gullstrand model eye (radius 12 mm), this corresponds to an angular deflection of the eye of less than about ±1°. This deflection is caused by an equally large deviation between the target direction and the actual direction of the target optical axis. Therefore, for the above-mentioned distance between the light source and the focal line, the deviation of the angular deflection of the eye can preferably be less than about 1°.

[0024] The terms "electromagnetic beam", "light" and "light beam" can be used as synonyms.

[0025] The term "substantially" can describe a slight deviation from a target value, particularly a deviation within the manufacturing accuracy range and / or within the necessary accuracy range, such that the effect present when at the target value is maintained. Therefore, the term "substantially" can include a deviation of less than about 30%, less than about 20%, less than about 10%, less than about 5%, less than about 2%, preferably less than about 1% from the target value and / or target position, etc. The term "substantially" includes the term "same", i.e., no deviation from the target value and target position.

[0026] The term "light field" describes an electromagnetic beam emitted by a planar object. For example, the planar object can be a component of a fixation target. For example, the planar object can be the curved surface of a cylindrical lens through which the electromagnetic beam exits the cylindrical lens. Although in this case the electromagnetic beam exits through the curved surface, the glasses wearer viewing the light field perceives the light field as being emitted, for example, by a flat (i.e., non-curved) planar object. A light field can also be radiated from the surface of, for example, a rectangular diffuser. In other words, the most general form of a "substantially rectangular light field" describes a light field having a longitudinal extent and a width extent, where the longitudinal extent can be, for example, greater than the width extent. The light field can also be substantially square, i.e., the longitudinal extent is approximately equal to the width extent. Thus, a substantially rectangular light field can be an electromagnetic beam emitted by a substantially rectangular surface, which surface is, for example, at least partially translucent and backlit. In particular, a substantially rectangular light field can be a light field whose projection onto a projection plane is substantially rectangular, where the projection plane is perpendicular to the electromagnetic beams that are parallel to each other, i.e., the projection plane is substantially perpendicular to a second plane (see below). The term "substantially rectangular" also includes shapes that deviate from a rectangle, such as having rounded corners, which shape is substantially oval, especially where the ratio of the major axis to the minor axis is greater than 1:2. To prevent the glasses wearer from deviating from their habitual head and body posture in order to fixate on an oval target for as long as possible, the target is preferably rectangular.

[0027] A "line" is not limited to a line in the mathematical sense. Instead, the term "line" also includes two-dimensional objects having a finite length and a finite width. Thus, a line can be a rectangle where the width of the rectangle is less than the length.

[0028] The term "uniform light", especially "uniform light" in one direction, describes light emitted by an illumination device especially in that direction having substantially the same light efficiency and / or luminous intensity. At all points of the illumination device that emit light in that direction, the emitted light has at least a similar, structure-independent intensity. Here, the intensity may, for example, decrease slightly towards the edges. If the emitted light is substantially uniform in that direction, the observer cannot distinguish individual light sources but instead sees a luminous line and / or, due to the finite extent of the illumination device, a luminous band and / or a luminous surface that emits light with a uniform intensity. This applies to various directions, especially to luminous surfaces.

[0029] The term "habitual head and body posture" is the basis for precise and tolerable centering of glasses. In particular, the "habitual head and body posture" essentially corresponds to the most natural head and body posture of the glasses wearer. For example, the glasses wearer can adopt the "habitual head and body posture" when looking in a mirror, because looking in a mirror is a situation that everyone is very familiar with every day. For example, compared with naturally looking into the distance, if the bridge of the nose of the test subject is fixed in the mirror image, the habitual head and body posture can be achieved.

[0030] In particular, the habitual head and body posture can correspond to the natural posture of the glasses wearer, which is determined by his physical and mental state, habits, daily life, occupation and leisure time.

[0031] Especially when the head is directly above the shoulders (and directly above the arch of the foot when extended downwards), the glasses wearer has a relaxed neck posture and a healthy, basically ideal head posture. Therefore, it is preferable to adopt the habitual head and body posture when standing.

[0032] In a basically ideal head posture, the head is basically directly above the shoulders (and directly above the arch of the foot when extended downwards). The ears are vertical and located above the center of the shoulders. The neck is only slightly concave, that is, bent inwards. In this position, the weight of the head is supported by the entire skeleton (i.e., the bones) through the spine. Since the neck muscles do not have to bear any weight, they are all soft, and the head can move freely on the spine. In all other head and / or neck positions, since the neck muscles must now resist gravity to hold the weight of the head, the neck muscles are tense for a long time. Depending on whether the head is stretched forward or backward or tilted to the right or left, and whether the neck is strongly bent or slightly bent here, different neck and body muscles are in a continuous state of contraction, that is, different muscles are tense. This can cause different types of head and neck pain. At the same time, the mobility of the neck is restricted because the muscles must fix the head in a specific position and can therefore only move within a limited range.

[0033] One aspect relates to a fixation target for generating a light field for aligning the line of sight direction of a glasses wearer when measuring the glasses wearer through a centering device. The fixation target includes a transparent lens body, and during operation, the electromagnetic beam of the generated light field is optically shaped through the lens body. During operation, the electromagnetic beam of the generated light field exits from the optical radiation surface of the lens body along the radiation direction. The back surface of the lens body is formed on the rear surface of the lens body facing away from the radiation surface. Here, the transparent lens body extends from the radiation surface in the direction opposite to the radiation direction to the back surface, and extends at least to the focal plane of the lens body.

[0034] For example, the fixation target can be designed to radiate a light field during operation, which light field is formed in a horizontal plane parallel to the propagation direction and diffused in the vertical direction. Thus, an eye within the area of the light field can be deflected in the horizontal direction parallel to the propagation direction of the light field, while remaining unaffected in the vertical direction. If such a fixation target is used in an alignment device, the propagation direction can be aligned such that the light field radiates from the alignment device towards the glasses wearer. If the glasses wearer fixates on the light field of the fixation target during measurement, the position of his eyes can be adjusted and / or controlled by the light field.

[0035] To avoid incorrect deflection of one or both eyes during measurement, the horizontal component of the light field direction can be formed uniformly and parallel over the entire area. Otherwise, the eyes will be deflected in a horizontal direction deviating from the light field direction, i.e., towards the corresponding local direction of the light field at the pupil position.

[0036] The fixation target can irradiate at least one measurement position with its light field, at which at least one eye of the glasses wearer can be located.

[0037] The fixation target has an optical lens, which is formed by a transparent lens body. For example, the transparent lens body can be made of glass and / or plastic. The transparent lens body optically shapes the electromagnetic beam by its shape and thus acts as a lens. In particular, the transparent lens body can have the shape and / or optical effect of a (for example, spherical or aspherical) cylindrical lens, which has a focal line arranged in the focal plane. Alternatively, the transparent lens body can have the shape and / or optical effect of a spherical lens, which has a focal point arranged in the focal plane.

[0038] In addition to the transparent lens body, the fixation target can also have a light source, the electromagnetic beam of which is optically shaped by the transparent lens body such that the light field of the fixation target is formed after the electromagnetic beam exits from the radiation surface.

[0039] For example, the optical radiation surface of the lens body can be designed to be at least partially convex and / or at least partially concave. The radiation surface can be designed to be spherical or aspherical. The radiation surface can be arranged at the operating position facing the glasses wearer. Thus, the light field exiting from the radiation surface can be used to align the line of sight of the glasses wearer.

[0040] The optical radiation surface of the lens body can form one side or at least one side of the transparent lens body, which radiation surface focuses the electromagnetic beam by its shape and / or optically shapes the electromagnetic beam in order to produce a predetermined and / or desired light field.

[0041] The back surface of the lens body, which is formed at the end of the transparent lens body facing away from the radiation surface, can be designed to be substantially flat and / or planar.

[0042] The position of the focal plane is different for a transparent lens body that includes the focal plane and a transparent lens body that terminates in front of the focal plane. This is because, in the former case, refraction occurs only once at the exit surface, while in the smaller transparent lens body, refraction occurs twice, i.e., when incident on the back surface and when exiting from the exit surface.

[0043] Compared with previously known fixation targets, the transparent lens body can be designed, for example, as a monolithic one. The transparent solid lens body is designed to extend in a direction opposite to the radiation direction. Thus, the lens body extends from the radiation surface at least to the focal plane of the lens body in a direction opposite to the radiation direction. The focal plane of the lens body can be formed at least partially or completely on the back surface of the lens body. The focal plane of the lens body can be formed at least partially or even completely inside the lens body. Theoretically, the focal plane can also be formed partially inside the lens body and partially on the back surface.

[0044] Here, the focal plane is the plane on which the transparent lens body focuses the light beam. Depending on the lens type, the lens body can focus the light beam, for example, on a focal line or a focal point. The light-emitting line arranged in the focal line generates an electromagnetic beam, which is substantially parallel to each other in at least one direction after exiting from the radiation surface. Similarly, the point light source arranged in the focal point generates an electromagnetic beam, which is substantially parallel to each other after exiting from the radiation surface.

[0045] By the shape of the transparent lens body extending in a direction opposite to the radiation direction, a predefined arrangement position can be provided for the light source of the fixation target. This simplifies the arrangement of the light source relative to the lens body. Thereby, the adjustment and / or assembly of the fixation target is simplified. Therefore, the elongated shape of the lens body can prevent misassembly and / or at least reduce the risk of misassembly.

[0046] Another advantage can be to improve the stability of the fixation target, because it has fewer individual components and thus these components are less likely to be misaligned.

[0047] According to one embodiment, a light generator is formed along at least a portion of the focal plane on and / or in the lens body. During operation, the light generator radiates an electromagnetic beam in the direction of the optical radiation surface such that the electromagnetic beam forms a light field generated by the fixation target after exiting from the radiation surface. Thus, the light generator is pre-mounted on and / or in the lens body. Accordingly, misalignment of the light source relative to the lens body can be significantly reduced or even completely avoided. The light generator can be designed, for example, as a light ray generator and provides a substantially linear light source. Alternatively, the light generator can be designed, for example, as a substantially point-like light source, i.e., as a light point generator. A "light point generator" does not refer to a mathematically (i.e., infinitesimal) point light source, but rather to a technically achievable substantially spherical small light source. The light generator itself does not have to be designed as an active (i.e., energy-driven) light source. For example, the light generator can simulate a light source by diffraction and / or scattering. Here, the light generator can optically manipulate an electromagnetic beam actually generated by another (e.g., external) electrical light source such that the electrical light source serves as its own light source.

[0048] In an improved example of this embodiment, the light generator is designed as a passive light generator that provides and / or generates an electromagnetic beam of the light field only when irradiated by a light source. As a passive component, the light generator itself is not energy-driven. It cannot generate a light beam by itself, but can only affect an existing light beam. In this case, the light generator can be designed, for example, as a diffraction slit, a perforated plate, and / or a line composed of scattering points. If the light ray generator is irradiated by an active light source such as at least one light bulb and / or LED, it forms a luminous line that radiates diffused light precisely in the focal line and / or focal plane of the lens body. The passive light generator can also be formed by at least one phosphorescent dye that generates an electromagnetic beam of the light field when irradiated, for example, by a UV light source.

[0049] In an improved example, the fixation target has a light source for irradiating the light generator such that the light generator forms an electromagnetic beam emitted by the light source and radiates it as an electromagnetic beam in the direction of the optical radiation surface such that the electromagnetic beam forms a light field generated by the fixation target after exiting from the radiation surface. The light source can be an active energy-driven light source. For example, the light source can be designed as at least one LED and / or light bulb and / or halogen lamp, or as a similar current-driven lighting fixture. Thus, compared with the passive light generator, the light generator is designed as an active light generator. Since the light generator (e.g., as a light ray generator or a light point generator) arranged in the focal plane optically converts the light generated by the light source into, for example, a luminous line or a light point, the light from the light source does not have to be adjusted and / or aligned particularly precisely relative to the lens body. Accordingly, the light generator significantly simplifies the assembly of the fixation target.

[0050] According to an embodiment, the focal plane is at least partially and precisely arranged on the back surface of the lens body. In this case, the back surface can be designed to be flat and / or planar. In the operating position, the back surface can be particularly arranged in a vertical plane. If the lens body has a focal line, the focal line can also be aligned substantially vertically in the operating position. If a light source (e.g., a light-emitting line) for the fixation target is now to be assembled, it can simply be placed on the back surface and can be moved into the focal line there. On the back surface, a focal line mark can be formed along the focal line. Similarly, a focus mark can also be provided for a point light source.

[0051] According to an improved example, the light generator is provided in such a way that, except for at least one part and / or region along the focal plane, the back surface of the lens body is blackened and / or roughened. In this case, except for, for example, a slit-shaped part along the focal line or a circular region around the focus, the back surface can be, for example, completely blackened and / or roughened. For example, if the back surface is irradiated by an LED as an active light source, a light field is generated by the lens body that can be used as a fixation target. Here, the roughening and / or blackening of the back surface can prevent multiple reflections. The blackened part produces, for example, a slit-shaped or circular aperture for the irradiated light. For example, the slit along the focal line can be designed to be narrower than about 1 cm, preferably narrower than about 5 mm, and particularly preferably narrower than about 1 mm. It has been proven that a slit width of about 0.5 mm is particularly suitable. Preferably, the same dimensions apply to the possible diameter of the circular aperture.

[0052] In an alternative embodiment, the focal plane is at least partially arranged inside the lens body. In this case, the focal plane is surrounded by the lens body. Thus, all components (e.g., the light generator) arranged on the focal plane are already integral parts of the lens body and no further adjustment is required. In this case, the lens body is designed to extend beyond the focal plane in the direction opposite to the radiation direction. Alternatively, a precisely matching recess for, for example, an active light-emitting line can be formed along the focal plane inside the lens body and / or in the focal plane, and the active light-emitting line is only inserted into this recess during assembly.

[0053] In an improved example of this embodiment, the light generator is provided in such a way that scattering centers are formed along at least a part of the focal plane inside the lens body. For example, the scattering centers can be introduced into the material of the lens body by a laser writing process. The scattering centers can be generated in a manner similar to engraving inside glass. To ensure that the scattering centers in the lens body volume are precisely arranged along the focal line or at the focus, these scattering centers can be generated by means of a light beam having the desired characteristics of the light field. In this case, the light beams can generally be irradiated onto the radiation surface in a manner parallel to each other and parallel to the optical axis of the fixation target. Thereby, these light beams are automatically focused on the focal line or at the focus, and scattering centers are generated there.

[0054] According to one embodiment, at least one outer surface of the lens body is at least partially blackened and / or roughened. In particular, these outer surfaces can be the lateral outer surfaces of the lens body, which extend along the sides, for example from the radiation surface to the back surface and / or from the top surface to the bottom surface. By blackening and / or roughening, reflections within the lens body can be reduced and / or avoided, for example. For example, the edge of the radiation surface can also be blackened to reduce adverse reflections.

[0055] According to one embodiment, at least one outer surface of the lens body is coated with an anti-reflection coating. Such anti-reflection coatings are commonly applied to spectacle lenses and are thus known to those skilled in the art. The anti-reflection coating can be applied to all outer surfaces of the lens body to reduce and / or avoid reflections.

[0056] According to one embodiment, the transparent lens body is designed as a spherical cylindrical lens or an aspherical cylindrical lens having a focal line arranged in the focal plane, or as a spherical lens or an aspherical lens having a focus arranged in the focal plane. In this case, the focal line of the cylindrical lens can be aligned substantially vertically in the operating position. In this case, the aspherical shape makes the geometry of the lens body more compact and / or the error at the edge of the lens body smaller. However, the manufacture of such an aspherical shape is more complex than that of a spherical shape. For calculating the shape, methods known to those skilled in the art can be referred to, and for example, reference is made to the document DE 10 2008 003 906 B4 and G. Esser et al.: "Derivation of the refraction equations for higher order aberrations of local wavefronts at oblique incidence", JOSA A, Vol. 27, No. 2 (2010). If the lens body is designed as a cylindrical lens, it has a focal line and is preferably combined with a light ray generator arranged on the focal line. If the lens body is designed as a spherical lens, it has a focus and is preferably combined with a light point generator arranged in the focus.

[0057] In an improved example of this embodiment, the light generator is designed as a light beam generator arranged substantially along at least a part of the focal line of the cylindrical lens, or the light generator is designed as a point light source arranged substantially at the lens focus. Depending on the design of the lens body, the light generator can be designed, for example, as a light beam generator and provide a substantially linear light source. Alternatively, the light generator can be designed, for example, as a substantially point-shaped light source, i.e., a light point generator. Here, the "light point generator" does not refer to a mathematically (i.e., infinitesimal) point light source, but to a technically achievable small light source of substantially spherical shape. In any case, the light generator itself does not have to be designed as an active (i.e., energy-driven) light source, but the light generator can, for example, simulate a light source by diffraction and / or scattering. The light generator is arranged on the focal line or at the focus such that a parallel beam is formed after passing through the lens body.

[0058] According to one embodiment, the transparent lens body is made by plastic injection molding and / or drawing. With this manufacturing method, the transparent lens body can be manufactured with particularly precise matching. The structure of the lens body as a plastic profile allows the geometric shape to be extended in the vertical range, thus enabling a larger structural height. Another option is the traditional grinding of plastic or mineral glass.

[0059] According to one embodiment, the fixation target is designed such that the electromagnetic beam of the light field is substantially diffused in a first predeterminable plane and the electromagnetic beam of the light field is substantially parallel in a second predeterminable plane arranged substantially perpendicular to the first predeterminable plane. In other words, the beam path can extend parallel in one direction and be diffused in a direction perpendicular to this direction. This gives the impression of a luminous surface to the glasses wearer, for example, the impression of a luminous surface in the form of a luminous band (especially a luminous line in the direction of diffuse radiation). Preferably, the light field is designed to be significantly wider than the pupil of the glasses wearer, i.e., at least 2 times, 5 times, 10 times, and / or 20 times wider than the pupil width of the glasses wearer. It has been proven that a width of approximately 32 mm is particularly suitable. Thus, as long as the glasses wearer is in the light field of the fixation target and sees the parallel light in the second plane, he can move his position without changing his visual impression. In other words, the visible light band will "drift (mitwandern)" as the glasses wearer moves.

[0060] Due to the formation of the light field, the line-of-sight direction of the glasses wearer when looking at the light field is determined by the direction of the light field (i.e., by the direction of the parallel beam). For example, if the first plane is the vertical plane in the Earth reference system and the second plane is the horizontal plane in the Earth reference system, the line-of-sight direction of the glasses wearer in the horizontal direction is determined by the direction of the light of the light field. In the vertical direction, the line-of-sight direction is restricted by the vertical range. Therefore, the glasses wearer can adopt his natural viewing posture within the light field.

[0061] In addition to the above-described embodiments, due to the parallel electromagnetic beams, when the glasses wearer looks at the light field of the fixation target, their line of sight will be directed towards "infinity". In other words, due to the parallel electromagnetic beams of the light field, the glasses wearer perceives the light field as being "infinitely" far away. Therefore, the glasses wearer adopts natural head and body postures that correspond to naturally looking into the distance, especially looking straight ahead into the distance. Advantageously, as long as the glasses wearer is looking at the parallel electromagnetic beams, the visual impression of the glasses wearer is substantially independent of the exact position of the eyes in front of the fixation target, especially in front of the light field. For example, as long as the parallel electromagnetic beams of the light field are seen, the glasses wearer can move their position in a direction parallel to the second plane (e.g., the horizontal direction). In the vertical direction, due to the diffuse electromagnetic beams, the glasses wearer can freely move their head, i.e., if the first plane is a vertical plane, for example, the glasses wearer can freely move their head in the vertical direction and adopt their natural head position. Therefore, due to the direction of the parallel light, the line of sight direction is only specified in one spatial direction, i.e., the horizontal direction. If the light field is wide, the glasses wearer can slightly turn and / or move their head if necessary, where the visible light band "drifts" with the horizontal movement of the head. If the light field is narrow, the head position of the glasses wearer is substantially restricted within the narrow light field range in the horizontal direction. In the exemplary vertical direction, the glasses wearer can freely choose their line of sight direction. This is particularly advantageous when adjusting progressive lenses.

[0062] One aspect relates to a manufacturing method for manufacturing a fixation target according to the above aspect. Here, this can in particular be the drawing method and / or the injection molding method, where the transparent lens body is made of plastic, for example. A part of the manufacturing method can also be the formation of the light generator, especially according to one of the above methods.

[0063] One aspect relates to a centering device for determining the optical centering parameters and / or individual parameters of a glasses wearer using a fixation target according to the above aspect.

[0064] For example, the centering device can be designed as the centering device disclosed in document DE 10 2005 003 699 A1. For example, the centering device can be designed as a video centering system. The centering device at least includes a fixation target, a measuring device, and a parameter calculation device. The centering device is designed and / or configured to determine optical centering parameters such as pupil distance, grinding height, corneal apex distance, etc. and / or individual parameters such as the lens plane angle (Fassungsscheibenwinkel) and / or the lens tilt angle (Vorneigung) (respectively in the use position).

[0065] To this end, the centering device may have a measuring device. For example, the measuring device may have at least two image acquisition devices, which are used to generate image data of the head of the glasses wearer from at least two acquisition directions. For example, the image acquisition device may generate a stereoscopic image of the head of the glasses wearer. Alternatively, the measuring device may also have only one image acquisition device and / or an illumination device such as a pattern projection device. In particular, the measuring device may be designed to generate image data of the head of the glasses wearer. The image data may include the head of the glasses wearer and the spectacle frame. Based on the image data, the measuring device may determine the measurement position of at least one eye of the glasses wearer. Preferably, the measuring device determines the measurement positions of both eyes of the glasses wearer.

[0066] The centering device does not have to be designed as a dual-camera system and may also be designed as a multi-camera system or a single-camera system. For example, the latter can be used together with a plug-in bracket.

[0067] The measuring device may also have other elements, such as a plane mirror, a lens, and / or a grating for deflecting the optical axis of at least one image acquisition device. In addition, the measuring device may, for example, have an illumination device, a processor, a memory, and / or a software implementation.

[0068] When generating the image data, the glasses wearer may be located at a predetermined distance in front of the centering device. When generating the image data, the glasses wearer preferably assumes his usage position, that is, he wears the spectacle frame in as natural a position as possible.

[0069] In order to control and / or align the line of sight of the glasses wearer when determining the (multiple) measurement positions, a light field is emitted by a fixation target. The light field may be designed as a substantially rectangular light field. The light field irradiates at least one eye of the glasses wearer, preferably irradiates at least two eyes of the glasses wearer, and particularly preferably irradiates the entire face of the glasses wearer. The glasses wearer may be instructed to fixate on the light field generated by the fixation target. Then, the light field of the fixation target affects and / or controls the measurement position and / or the measurement attitude of the eyes.

[0070] One aspect relates to the use of a fixation target according to the above aspects, which is used as an auxiliary tool for aligning the line of sight direction of the glasses wearer and / or at least one eye in a defined manner, wherein a planar light field is generated by the fixation target and the glasses wearer fixates on the light field. Here, the fixation target may be particularly used for the centering device so as to be able to determine the optical centering parameters and / or centering data of the eye wearer in the corresponding aligned line of sight in this way.

[0071] One aspect relates to a method for determining centering parameters and / or individual parameters of an eyewear wearer, wherein the line of sight direction and / or at least one eye of the eyewear wearer is / are aligned in a defined manner with respect to a fixation target according to the above aspect, and the centering parameters and / or individual parameters are determined at the thus-defined aligned position of the eyewear wearer.

[0072] Unless otherwise specified, terms such as up, down, above, below, lateral, etc. refer to the Earth reference system in the operating position of the subject matter of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The present invention will be described in more detail below based on the exemplary embodiments shown in the drawings. In this case, the same or similar reference numerals may represent the same or similar features of the embodiments. The individual features shown in the drawings may be implemented in other exemplary embodiments.

[0074] Figure 1 A centering device for measuring an eyewear wearer is shown in a schematic perspective view.

[0075] Figure 2 A conventional fixation target of the centering device is shown in a schematic perspective view.

[0076] Figure 3 A conventional fixation target of the centering device is shown in a schematic top view.

[0077] Figure 4 A lens body of an embodiment of the fixation target is shown in a schematic perspective view.

[0078] Figure 5 Shown in a schematic rear view Figure 4 the lens body shown.

[0079] Figure 6 A beam path through an embodiment of the fixation target is shown in a schematic top view, wherein the focal plane of the lens body is arranged in the flat rear side of the lens body.

[0080] Figure 7 A beam path through a second embodiment of the fixation target is shown in a schematic top view; wherein the focal plane of the lens body is arranged inside the lens body and spaced apart from its spherical rear side.

[0081] Figure 8 A beam path through a third embodiment of the fixation target is shown in a schematic top view, wherein the focal plane of the lens body is arranged inside the lens body and spaced apart from its flat rear side. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0082] Figure 1Fig. 0 shows a schematic perspective view of an alignment device 10 for determining the optical alignment parameters of a spectacle wearer 30. The alignment device 10 has an arrangement device in the form of a housing and / or a column 12, on which a first image acquisition device 14 in the form of an upper camera and a second image acquisition device 16 in the form of a side camera are arranged. In addition, a data output device in the form of a monitor 18 is integrated into the column 12.

[0083] Preferably, the upper camera 14 is located inside the column 12, for example, as Figure 1 shown, at least partially at the same height as the monitor 18. In the operating position, the upper camera 14 and the side camera 16 are arranged such that they can generate image data of the head of the spectacle wearer 30. Here, the effective optical axis 20 of the upper camera 14 can intersect the effective optical axis 22 of the side camera 16 at an intersection point 24. Preferably, the intersection point 24 of the effective optical axes 20, 22 is the nasion or the center point of the nasal bridge.

[0084] The upper camera 14 can be centrally arranged behind a semi-transparent plane mirror 26. The image data of the upper camera 14 is generated through the semi-transparent plane mirror 26. Preferably, the image data (hereinafter referred to as images) of the upper camera 14 and the side camera 16 are output to the monitor 18.

[0085] In addition, (for example, three) lamps 28 can be arranged on the column 12 of the alignment device 10. For example, the lamps 28 can be light-emitting rods such as fluorescent tubes. However, the lamps 28 can also each have one or more bulbs, halogen lamps, light-emitting diodes, etc.

[0086] For example, the effective optical axis 20 of the upper camera 14 can be arranged parallel to the zero line of sight direction of the spectacle wearer 30. The zero line of sight direction corresponds to the fixation lines of the eyes of the spectacle wearer 30 in the basic position. The side camera 16 can be arranged such that the effective optical axis 22 of the side camera 16 intersects the effective optical axis 20 of the upper camera 14 at the intersection point 24 at an intersection angle of, for example, approximately 30°. Preferably, the intersection point 24 of the effective optical axes 20, 22 is the nasion of the spectacle wearer 30. In this case, other intersection angles are also possible, for example, the intersection angle can be less than approximately 60°. The effective optical axes 20, 22 do not necessarily have to intersect.

[0087] The cameras 14, 16 can be designed to respectively generate separate images of partial regions of the head of the spectacle wearer 30. Video sequences can also be recorded by the cameras 14, 16 and these video sequences can be used for further evaluation. The image data and / or images can be recorded in a time-synchronized manner for further evaluation.

[0088] In the operating position, the glasses wearer 30 can be arranged and / or positioned such that his line of sight points to the semi-transparent planar mirror 26, where the user looks, for example, at the image of the root of his nose in the mirror image of the semi-transparent planar mirror 26.

[0089] The image acquisition devices 14, 16 can be elements of the measuring device of the centering device 10. Other elements of the measuring device can, for example, be arranged inside the housing 12, and other elements are, for example, a processor, a memory, and / or software. Based on the image data recorded by the image acquisition devices 14, 16, the measuring device can determine the measuring position of at least one eye of the glasses wearer 30, preferably the measuring positions of the two eyes of the glasses wearer 30.

[0090] The centering device 10 also has at least one fixation target 40. Here, the centering device 10 can also have two fixation targets 40, which are, for example, used to align the glasses wearer 30 at different positions.

[0091] Preferably, when the glasses wearer 30 gazes at the light field emitted in a controlled manner by the fixation target 40, the measuring device can accurately record the image data of the glasses wearer 30.

[0092] Figure 2 A schematic perspective view of a conventional fixation target 40 is shown. The fixation target 40 has a cylindrical lens 42 and a light source 41. The light source 41 can, for example, include an LED (especially a homogeneous LED), an incandescent lamp, and / or a similar active light source. For example, the light source 41 can be arranged approximately on the focal line of the cylindrical lens 42.

[0093] In the illustrated embodiment, the light source 41 is, for example, designed to be rod-shaped and / or cylindrical. Thus, the light source 41 can basically be designed as a light-emitting line. The rod-shaped light source 41 is arranged approximately vertically, that is, the cylinder axis of the light source 41 is arranged approximately vertically. In the figure, the vertical direction is marked as the y-direction of the Cartesian coordinate system.

[0094] The cylinder axis of the cylindrical lens 42 is also arranged approximately vertically, that is, along the y-direction. The light source 41 is spaced apart from the cylindrical lens 42 in the negative z-direction. Here, the z-direction is a direction that is approximately horizontally aligned and is approximately perpendicular to the convex surface of the cylindrical lens 42 in the direction in which the light source 41 radiates the light field through the cylindrical lens 42.

[0095] Figure 3 A schematic top view of a conventional fixation target 40 is shown. Here, it is shown how the light radiated by the light source 41 irradiates the substantially flat back surface of the cylindrical lens 42. This light penetrates the cylindrical lens 42 and exits as a substantially parallel-aligned light beam 50 from the convex surface of the cylindrical lens 42 that is away from the light source 41. The light beam 50 forms the light field actually generated and / or radiated by the fixation target 40.

[0096] The light beams 50 are aligned approximately parallel to each other in the x-z plane and radiate approximately in the z direction, i.e., approximately horizontally away from the fixation target 40 (and the centering device 10) in the direction towards the spectacle wearer 30 (see also Figure 1 the coordinate system shown). Thus, the z direction coincides with the optical axis of the fixation target. In the y direction, the light beams 50 are diffused.

[0097] Ideally, the light source 41 is arranged exactly on the focal line of the cylindrical lens 42. In this way, the electromagnetic beam provided by the light beam 50 is completely parallel. If the cylinder axis and the focal line of the cylindrical lens 42 are arranged exactly perpendicular to each other, the light beam 50 propagates completely in the horizontal plane in the earth reference system. For example, Figure 3 such an x-z plane is shown.

[0098] The x direction of the coordinate system used is also arranged approximately horizontally, perpendicular to the y direction and the z direction, and points in the lateral direction away from the fixation target 40 (see Figure 2 ). For example, the x direction can be arranged approximately parallel to the flat back surface of the cylindrical lens 42 that is aligned with the focal line, and / or point in the lateral direction.

[0099] The optical axis of the fixation target 40 is an axis that is aligned in a manner substantially parallel to the electromagnetic beam of the light beam 50. Thus, the optical axis of the fixation target points in the z direction.

[0100] The light field of the fixation target 40 is formed by the vertical diffused light source 41 and the vertically oriented cylindrical lens 42. In this case, the diffused light source 41 is arranged on the focal line, which is arranged on the cylinder axis of the convex cylindrical front surface of the cylindrical lens 42. The resulting light field (see Figure 3 ) is formed in the x direction in the horizontal plane (x-z plane) parallel to the axis of the fixation target 40 and is diffused in the vertical y direction. Thus, the eyes in the light field region are deflected in the horizontal direction parallel to the axis of the fixation target during fixation, but are not affected in the vertical direction.

[0101] In this case, the focal line does not have to be located outside the lens element of the cylindrical lens 42 (as shown in Figure 2 and Figure 3 ). In the overall structure, the focal line and thus the emission line can also be located on the back surface of the lens element or inside the lens element (see the figure below).

[0102] If the fixation target 40 is used in the centering device 10 and / or the video centering system, the axis (z-axis) of the fixation target can be aligned parallel to the axis of the centering device 10. This axis of the centering device 10 can be, for example, the effective optical axis of one of the image acquisition devices, for example the first effective optical axis 20 of the first image acquisition device 14. Generally, the axis of the fixation target 40 can be arranged parallel to the effective optical axis of a centering device with only one camera, parallel to the effective optical axis of the main camera of a centering device with more than two cameras, or parallel to the symmetry axis of a centering device with a plurality of cameras arranged laterally with respect to each other. In the case of a centering device with a plane mirror 26, the spectacle wearer 30 can observe themselves in the plane mirror 26, and the axis of the centering device can also be defined according to the direction of the plane mirror surface (usually defined as the normal to the plane mirror surface).

[0103] To avoid incorrect deflection of the eyes of the spectacle wearer 30, the horizontal component of the light field direction should be arranged uniformly parallel and parallel to the axis of the centering device 10 over the entire area. Otherwise, the eyes will deflect in a horizontal direction away from the target direction, i.e., in the corresponding local direction of the light field at the pupil position of the spectacle wearer 30.

[0104] To provide such a light field, a conventional fixation target must meet two conditions: First, the cylindrical lens 42 must have almost no imaging error, which places high demands on its production. Second, the diffused light source 41 must be precisely located on the focal line of the cylindrical lens 42. This requires an adjustable system and / or precisely matched components. An adjustable system requires complex optical and mechanical devices to enable the mutual adjustment of the two optical elements 41, 42 and their adjustment relative to the axis of the centering device 10. For this purpose, complex adjustments are also required during and / or after production. The precisely matched components should have small tolerances and be correspondingly matched so that when the components are assembled together, a light field of the necessary quality is inevitably produced due to the tolerance chain. This places particularly high demands on the production of the cylindrical lens 42. The required tolerances regarding the lateral and axial positions of the focal line relative to the surface elements of the cylindrical lens 42 cannot be achieved by low-cost standard processes.

[0105] This applies particularly to light fields with a large lateral extent (especially in the x-direction) because the imaging error of the lens has a particularly obvious effect here (especially in the case of a simple cylindrical lens with a spherical cross-section). To avoid imaging errors, lenses with a particularly complex manufacturing process with a non-spherical cross-section are required.

[0106] The object of the present invention may be to provide a device and a method as follows, which can achieve high precision in measuring parameters of an eye and / or an eyewear-eye system (in particular, optical centering parameters) at a relatively low manufacturing cost, using components and / or systems with relatively low requirements. Examples of these parameters are known centering parameters and individual parameters, as well as the position of the center of eye rotation, the position, shape and size of the pupil, and the position of the corneal apex.

[0107] In order to reduce the costs listed above, the conventional fixation target 40 can be replaced by the following fixation target 70 according to the present invention.

[0108] Figure 4 A lens body 60 of an embodiment of the fixation target 70 is shown in a schematic perspective view (see Figure 6 ). The lens body 60 is integrally designed and extends from its flat back surface 62 to its convex radiation surface 61 in the radiation direction A, which can be aligned in the operating position to be substantially or precisely parallel to the z direction (see Figure 1 ).

[0109] The radiation surface 61 can be designed as a spherical or aspherical surface. The radiation surface 61 can have the shape of a cylindrical lens aligned in the y direction (i.e., the vertical direction, for example).

[0110] The shape of the radiation surface 61 can be similar to Figure 2 and Figure 3 the radiation surface of the cylindrical lens 42 shown. However, different from the shown cylindrical lens 42, the lens body 60 is designed to extend to its flat back surface 62 in the direction opposite to the radiation direction A. However, since no refraction occurs at the back surface 62 in the lens body 60 between the focal line 69 and the radiation surface 61, the arrangement of the focal line 69 relative to the radiation surface 61 is different from that of the previously known cylindrical lens 42.

[0111] In the operating position, the back surface 62 can be aligned in a vertical plane, which is arranged to be substantially perpendicular to the radiation direction A, for example, substantially parallel to the x-y plane. The radiation surface 61 is shaped such that it forms a cylindrical lens, and its focal line 69 extends precisely along the back surface 62. The focal line 69 is shown as a dashed line in Figure 4 . The focal line 69 is located in the focal plane of the lens body 60.

[0112] The lens body 60 is made of a transparent material, for example, made of glass and / or plastic. The material of the lens body 60 is used to provide an outer surface for optically shaping light when the light exits from and / or enters into the lens body 60.

[0113] The lens body 60 may also have two opposite lateral sides 63, each of which may be arranged to be substantially perpendicular to the back side 62. The radiation surface 61, the back side 62, and possibly the lateral sides 63 may define the lens body 60 in all horizontal directions. In addition, the lens body 60 may also have a top surface and a bottom surface, which may define the lens body 60 upwardly and downwardly. The back side 62, the lateral sides 63, the top surface, and / or the bottom surface may be designed as flat surfaces, while the radiation surface 61 may be designed as a concave and / or convex surface.

[0114] The back side 62 has a light generator along the focal line 69, which is designed as a light ray generator 65 and is used to diffract and / or refract the light incident on the back side 62 substantially in the radiation direction.

[0115] Figure 5 A cross-section of the lens body 60 is shown in a schematic rear view of the back side 62. Since the back side 62 is provided with a blackening portion 66 (shown in Figure 5 by hatching), the back side 62 is almost completely blackened. Only the narrow slit along the focal line 69 is not blackened and thus remains transparent. It is this non-blackened slit that provides the light ray generator 65, which is also formed and arranged in the focal line 69.

[0116] For example, the blackening portion 66 can be implemented as a photoresist. This can be irradiated from the radiation surface 61 by a backward-directed target light field, for example, using a backward-directed parallel beam 50 (see Figure 3 and Figure 6 ), so that only the focal line 69 is irradiated. If a positive resist is used as the blackening portion, the remaining resist after development forms the blackening portion 66, while the slit for the light ray generator 65 is retained. Therefore, it can be ensured that the retained slit is accurately formed on the back side 62 along the focal line 69.

[0117] As an alternative or supplementary solution to the blackening portion 66, the back side 62 (for example, except for the slit) can also be roughened.

[0118] In addition, for example, the lateral sides 63 and / or the top surface and the bottom surface can be blackened and / or roughened to reduce scattered light.

[0119] Figure 6 A beam path of an embodiment passing through the fixation target 70 is shown in a schematic top view. The fixation target 70 has a lens body 60 and a light source 71 arranged near the back side 62. The light source 71 does not have to radiate diffused light. The light source 71 can be designed as a common (active) light source, for example, designed as an LED.

[0120] The light source 71 irradiates the back side 62 of the lens body 60, where the blackening portion 66 reduces and / or prevents light from penetrating into the lens body 60 at any position other than along the non-blackened slit.

[0121] In this case, the "blackening section" 66 does not necessarily mean that the back surface 62 actually has to be colored "black". It can also be colored in a different color (preferably a dark color), covered with a coating, and / or roughened. For example, slits in the blackening section 66 can be produced by means of a normal coating and / or pigment, where the slits are covered with tape before applying the coating and / or pigment. After the coating and / or pigment has dried, the covering can be removed and thus voids are formed. The covering can also be provided by a photoresist. Here, the area to be blackened (using a negative resist) or the area not to be blackened (using a positive resist) can be exposed. This also applies to the case of roughening at the location of the blackening section 66.

[0122] The slits of the light generator 65 act as slit-shaped apertures for the light from the light source 71 and thus produce diffused light in the focal line 69, which exits from the radiation surface 61 as a parallel light beam 50. The light beams 50 are parallel to each other in the horizontal direction and radiate in the radiation direction A.

[0123] These light beams 50 form the light field of the fixation target 70. The light field is produced by the cylindrical lenses of the lens body 60, which can be used as, for example, the fixation target in the centering device 10 (see Figure 1 ). Here, the blackening section 66 or the roughened section of the back surface 62 reduces multiple reflections. By additionally blackening or roughening the side surfaces of the lens body 60, multiple reflections can be further reduced.

[0124] In an alternative embodiment not shown in the figure of the lens body, the focal line is arranged in the volume of the lens body. In the case of this structure, the luminous line can be produced by scattering at the scattering center, which is precisely formed at the location of the focal line. Here, (different from the Figures 4 to 6 shown embodiment) the structural length of the lens body in the direction opposite to the radiation direction is slightly longer than the focal length.

[0125] For example, a laser writing method similar to the internal engraving of glass can be used to introduce the scattering centers into the material of the lens body.

[0126] The scattering centers can be irradiated by an illumination light source to form these scattering centers, and the light of this illumination light source is coupled to the side of the lens body that is not (e.g., not yet) roughened. This can be done on the top surface and / or the bottom surface, and / or on one or both side surfaces, and / or through the radiation surface.

[0127] To ensure that the scattering centers within the lens body volume are precisely located on the focal line of the front radiation surface, the scattering centers can be generated by means of a light beam having desired characteristics, such as a beam that is parallel to each other and is also aligned in a manner parallel to the axis of the fixation target. This beam can be incident through the radiation surface and thus be focused at corresponding points along the focal line.

[0128] The fixation target allows for the generation of a light field by a single component that simultaneously functions as the cylindrical lens, barrel, and (passive) light-emitting line of the fixation target.

[0129] Accordingly, the number of components required for the fixation target can be reduced, thereby correspondingly reducing costs.

[0130] According to the selected geometry, by eliminating the interface between the cylindrical lens 42 and the light source 41 (see Figure 2 and Figure 3 ), multiple reflections can be prevented, which allows for the omission of an anti-reflection coating at this interface.

[0131] Since there is no need to adjust the light source relative to the lens body to generate a correctly aligned light field, the fixation target can be adjusted and manufactured very quickly and cost-effectively.

[0132] Since the fixation target 70 has fewer individual components and is thus less likely to be misaligned, the stability of the fixation target 70 can be improved.

[0133] Figure 7 A beam path through a second embodiment of the fixation target 70 is shown in a schematic top view. Here, the light generator 65 is designed as a passive component inside the lens body 60, i.e., for example, a series of scattering centers and / or phosphorescent dyes along the focal line 69. The lens body 60 extends from a spherical or aspherical radiation surface 61 in a direction opposite to the z-direction to a convex (e.g., spherical or aspherical) back surface 62.

[0134] The light generator 65 is irradiated by two light sources 71 arranged on the side surface 63, thus exciting the light generator 65 to provide a light beam 50 (see also Figure 6 ). The light sources 71 can be designed as, for example, planar LEDs and are arranged adjacent to and / or in the vicinity of the side surface 63. Here, the light sources 71 can be arranged, for example, in a focal plane that is arranged along the focal line 69 in the x-y plane.

[0135] A mirror coating 67 can be arranged on the back surface 62 to be able to couple the scattered light into the light generator 65. Here, the mirror coating can extend, for example, from the upper end to the lower end of the lens body 60 in the y-direction and / or cover at least the central region of the back surface 62, which is opposite to the radiation surface 61 with respect to the focal line 69 (in Figure 7(marked as a straight dashed line in the figure). Other outer surfaces of the lens body 60 (e.g., the side surfaces 63, the regions of the back surface 62 adjacent to the mirror coating 67, and / or the edges of the radiation surface 61) can be at least partially designed to be antireflective, blackened, and / or roughened. Preferably, the radiation surface 61 is designed to be (e.g., completely) antireflective.

[0136] Figure 8 A schematic top view shows the beam path of a third embodiment passing through the fixation target 70, in which the light generator 65 is also designed as a passive component inside the lens body 60, i.e., for example, a series of scattering centers and / or phosphorescent dyes along the focal line 69. The lens body 60 extends from a spherical or aspherical radiation surface 61 in a direction opposite to the z - direction to a flat back surface 62.

[0137] Similar to Figure 7 the embodiment shown, the light generator 65 is irradiated by two light sources 71 arranged on the side surface 63, thus exciting the light generator 65 to provide the light beam 50 (see also Figure 6 ). The light sources 71 can be designed as, for example, planar LEDs and are arranged adjacent to and / or in proximity to the side surface 63. Here, the light sources 71 can be arranged, for example, in a focal plane that is arranged along the focal line 69 in the x - y plane.

[0138] The outer surfaces of the lens body 60 (i.e., for example, the side surfaces 63 on both sides beside the light sources 71, the back surface 62, and / or the edges of the radiation surface 61) can be at least partially designed to be antireflective, blackened, and / or roughened. Preferably, the radiation surface 61 is also designed to be (e.g., completely) antireflective.

[0139] List of reference numerals

[0140] 10 Centering device

[0141] 12 Housing

[0142] 14 First image acquisition device

[0143] 16 Second image acquisition device

[0144] 18 Monitor

[0145] 20 First effective optical axis

[0146] 22 Second effective optical axis

[0147] 24 Intersection point

[0148] 26 Plane mirror

[0149] 28 Lamp

[0150] 30 Glasses wearer

[0151] 40 Gazing target

[0152] 41 Light source

[0153] 42 Cylindrical lens

[0154] 50 Light beam

[0155] 60 Lens body

[0156] 61 Radiation surface

[0157] 62 Back surface

[0158] 63 Side surface

[0159] 65 Light ray generator

[0160] 66 Blackening part

[0161] 67 Mirror coating

[0162] 69 Focal line

[0163] 70 Gazing target

[0164] 71 Light source

[0165] A Light beam direction

Claims

1. A fixation target (70) for generating an optical field for aligning the line of sight direction of an eyewear wearer (30) when measuring the eyewear wearer (30) by a centering device (10), the fixation target comprising: - A transparent lens body (60) that optically shapes the electromagnetic beam of the generated optical field during operation; - The optical radiation surface (61) of the lens body (60) from which the electromagnetic beam of the generated optical field exits in the radiation direction (A) during operation; and - The back surface (62) of the lens body (60) which is located on the rear surface of the lens body (60) facing away from the radiation surface (61), characterized in that the transparent lens body (60) extends from the radiation surface (61) in a direction opposite to the radiation direction (A) to the back surface (62), and extends at least to the focal plane of the radiation surface (61) of the lens body (60), wherein a light generator (65) is formed along at least a part of the focal plane on and / or in the lens body (60), and during operation, the light generator radiates an electromagnetic beam in the direction of the optical radiation surface (61) such that the electromagnetic beam forms the optical field generated by the fixation target (70) after exiting from the radiation surface (61).

2. The fixation target (70) according to claim 1, characterized in that the light generator (65) is designed as a passive light generator (65) which provides the electromagnetic beam of the optical field only when irradiated by a light source (71).

3. The fixation target (70) according to claim 1 or 2, characterized in that the fixation target (70) has a light source (71) for irradiating the light generator (65) such that the light generator (65) forms an electromagnetic beam emitted by the light source (71) and radiates it as an electromagnetic beam in the direction of the optical radiation surface (61) such that the electromagnetic beam forms the optical field generated by the fixation target after exiting from the radiation surface (61).

4. The fixation target (70) according to claim 1 or 2, characterized in that the focal plane is at least partially and precisely arranged on the back surface (62) of the lens body (60).

5. The fixation target (70) according to claim 4, characterized in that the light generator (65) is provided in such a way that, except for at least one part and / or region along the focal plane, the back surface (62) of the lens body (60) is blackened and / or roughened.

6. The fixation target (70) according to claim 1 or 2, characterized in that the focal plane is at least partially arranged inside the lens body.

7. The fixation target (70) according to claim 6, characterized in that the light generator is provided in such a way that scattering centers are formed along at least a part of the focal plane inside the lens body.

8. The fixation target (70) according to claim 1 or 2, characterized in that, at least one outer surface (61, 62, 63) of the lens body (60) is at least partially blackened and / or roughened.

9. The fixation target (70) according to claim 1 or 2, characterized in that, at least one outer surface (61, 62, 63) of the lens body (60) is coated with an anti-reflection coating.

10. The fixation target (70) according to claim 1 or 2, characterized in that, the transparent lens body (60) is designed to be: - a spherical or aspherical cylindrical lens having a focal line (69) arranged in the focal plane, or - a spherical or aspherical lens having a focus arranged in the focal plane.

11. The fixation target (70) according to claim 10, characterized in that: - the light generator is designed as a light ray generator (65) arranged along at least a part of the focal line (69) of the cylindrical lens, or - the light generator is designed as a point light source arranged in the focus of the lens.

12. The fixation target (70) according to claim 1 or 2, characterized in that, the transparent lens body (60) is made by plastic injection molding and / or drawing.

13. The fixation target (70) according to claim 1 or 2, characterized in that, the fixation target (70) is designed such that: - the electromagnetic beam of the light field is diffused in a first predeterminable plane, and - the electromagnetic beam of the light field is parallel in a second predeterminable plane arranged perpendicular to the first predeterminable plane.

14. An alignment device (10) for determining the optical alignment parameters and / or individual parameters of an eyewear wearer (30), characterized in that, the alignment device (10) has a fixation target (70) according to any one of the preceding claims.

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