WO2016162167A1

WO2016162167A1 - Device for data reflection

Info

Publication number: WO2016162167A1
Application number: PCT/EP2016/055250
Authority: WO
Inventors: Michael Patra
Original assignee: Carl Zeiss Smart Optics Gmbh
Priority date: 2015-04-07
Filing date: 2016-03-11
Publication date: 2016-10-13
Also published as: DE102015105233A1

Abstract

The invention relates to optical elements and devices for data reflection, comprising a Fresnel element which allows the illumination of a desired zone of a retina (16) without vignetting by the Fresnel element (60).

Description

description

DEVICE FOR DATA INTERVENTION

The present application relates to devices for data reflection, in particular for so-called data glasses, and optical element for such devices.

Generic devices are commonly used to provide data to a user for viewing. The term "data" is to be understood in a broad sense: Provided data may include, for example, characters, words, numbers, images or videos Such methods and devices are used, for example, in so-called head-up displays (HUDs), for example in the automobile sector or in so-called In general, an image is generated in accordance with the data to be imprinted, which can be viewed by one or both eyes of a user.

One possibility is the use of a display, which represents a einzuspiegelndes image, the image is then directed by appropriate optical components to one eye or both eyes of the viewer, in many applications superimposed with a view of the environment. In this case, the retina of one eye (or both eyes) is located conjugated to the display so that a bijective function exists between places on the display and places on the retina. Such a device is described for example in US 2012/0086623 A1 or US 2014/0226215 A1.

Another possibility for image generation is the use of a scanner device in which a highly collimated light beam emitted by a light source, for example a laser beam, is deflected by means of a deflection device so as to generate an image by scanning. By means of such a deflection device, an entire desired useful area is scanned on a retina of an eye, in particular in the end effect, and the intensity and / or color of the light source is adjusted in synchronized time. Imaging with such a scanner device is described, for example, in the already mentioned US 2014/0226215 A1 or US 2014/0139404 A1. Fig. 1 shows an example of such a device. In the apparatus of Fig. 1, a light source 10, for example a laser light source, generates a light beam. The light beam is directed to a movable mirror 1 1, which serves as a deflection device to ultimately raster a retina 16 of an eye 14. For this purpose, the reflected from the mirror 1 1 light beam is coupled in the device of FIG. 1 in a spectacle lens 12 of a data glasses. The term "spectacle lens" is chosen here for the sake of simplicity and is not to be considered as limiting the material.

In particular, the spectacle lens 12 may also be made of one or more plastics. The light beam coupled into the spectacle lens 12 is decoupled via a beam splitter 16 and directed to a pupil 15 of the eye 14. 17 denotes a point in which all light rays intersect. The beam splitter 16 may be at others

Embodiments also be designed so that all incident on him light is directed to a pupil 15 of the eye 14 out.

In such devices, there is substantially a bijective function between the location on the retina 16 and an orientation (expressed, for example, by one or more angles) of the mirror 1 1. The retina 16 is Fourier-conjugate to the

Beam deflection device, in this case the mirror 1 1, arranged. For a given optical design and arrangement of the retina relative to the device, the beam path is thus substantially uniquely determined by a particular location on the retina. This applies at least locally. For very large angular deviations of the mirror 11, it could happen that the same point on the retina would again be reached, provided that the pupil 15 is sufficiently large, for example by two reflections more inside the spectacle lens 12. This limitation of the above one-to-one (bijective function ) is however usually not relevant in practice and is therefore neglected in the following.

Depending on the optical design, the beam path for a fixed location on the retina 16 is different. In particular, the position of an intersection of the rays, if present, can be determined by the optical design. In Fig. 1, the intersection 17 is, for example, substantially in the pupil 15. In other variants, the intersection may also be behind the pupil 15. Such a variant is shown in FIG. Here, the point of intersection 20 lies within the eye 14. US 2014/0139404 A1 describes advantages of an arrangement as in FIG. 2, in which the point of intersection 20 between the pupil 15 and an eye rotation center is located during a movement of the eyes. In this case, rays that would form an image only outside of a central sea area of greatest sharpness of the retina 16 are vignetted to the eye pupil. As a result, peripheral image components, which would be irritating in some circumstances, even without eye tracking, ie without tracking an eye movement avoided.

In this case, a vignetting of certain parts is desired. Under a vignetting is as usual in the optics to understand a darkening of certain image area.

In FIGS. 1 and 2, essentially infinitely thin light beams are assumed. However, in practice, rays have a finite diameter greater than zero. Depending on the beam diameter, this can also lead to vignetting. This will now be explained with reference to FIG.

Fig. 3 shows, in the sub-figures A-C, the eye 14 in a position in which the pupil is directed straight ahead. In this case, three different width light beams 30, 31 and 32 are shown in Figures A-C. For example, sub-figures A-C show a reference situation, i. a reference position and reference orientation for eye and data glasses. This results in each case a picture of certain intensity on the retina 16.

The sub-figures D-F show the eye 14 in a slightly rotated position relative to the direction of incidence of the light beam, again for the three differently wide light beams 30, 31 and 32nd

In the case of the comparatively thin light beam 30, whose beam diameter is much smaller than the diameter of the pupil 15, regardless of the position of the eye 14, the entire light beam reaches the retina 16. Thus, there is no vignetting.

The beam 31 approximately corresponds in width to the width of the pupil 15. In FIG. 3B, the total beam intensity reaches the retina 16. In contrast to this, the change in position of the eye 14 in FIG. 3E shades off part of the beam diameter, resulting in a Vignetting, ie leads to a reduction in image intensity on retina 16. Such a change in intensity can be troublesome for a user and should be avoided.

In the case of Figures C and F, the beam diameter of the beam 32 is significantly larger than the diameter of the pupil 15. Here, in the cases of Figures 3C and 3F, each part of the beam is shaded, wherein the shadowed by the pupil 15 proportion in percent Essentially not changed. Thus, in this case, there is essentially no change in the Vignetting and thus essentially no change in the image intensity on the retina 16 of a user.

In order to avoid vignetting, it is therefore helpful to either choose the beam diameter of a beam used in the pupil 15 to be sufficiently smaller or sufficiently larger than the diameter of the pupil 15. If the beam diameter is sufficiently larger than the pupil diameter, however, relatively much useful light is lost due to shading. In addition, the optical quality of the device must generally be better to avoid unwanted leaching of the retinal dot image. Therefore, for devices in which the image is generated by scanning as illustrated in Figure 2, it is generally preferred to use a beam diameter smaller than the pupil diameter.

In the devices shown in FIGS. 1 and 2, a beam splitter 13 is used in the spectacle lens 12. In another approach, which is shown in Fig. 4, instead of the beam splitter 13, a Fresnel element 40 is used for decoupling. Apart from the use of the Fresnel element 40 instead of the beam splitter 13, the device of FIG. 4 corresponds to the device of FIG. 1. It should be noted that, depending on the design of the Fresnel element 40, an intersection of the rays at different locations is also here can.

With such a Fresnel element, however, additional vignetting may occur. This is shown in FIG. 5. FIG. 5 shows an enlarged detail from FIG. 4 with the Fresnel element 40 and, illustratively, five possible beams 50A-50F which can strike a facet 40A of the Fresnel element. As can be seen, the beams 50A and 50B are at least attenuated by the previous facet of the Fresnel element, which then results in vignetting on the retina 16. In other words, for example, in the configuration of Fig. 5, approximately half of the rays are vignetted. Thus, about half of the "pixels" on the retina remain darkened When using a display which is optically conjugate to the retina 16, this would be less critical, since such displays typically have a high light-conducting value and a high light-conductance the display (source) would illuminate a point on the retina across many facets of the Fresnel element However, this generally does not apply to the use of a scanner device as in Fig. 4, ie a Fourier conjugate device. It is therefore an object of the present invention to provide ways to avoid or at least reduce vignetting in the use of Fresnel elements in such devices. This object is achieved by an optical element according to claim 1 or 2. The

Subclaims define further embodiments of the optical element and a device for data reflection with such an optical element.

According to a first aspect, an optical element for a device for

Data entry provided comprising a carrier and a carrier in the

provided Fresnel element for directing light coupled in the carrier to an eye of an observer, wherein the Fresnel element has a plurality of facets, wherein the Fresnel element is formed such that on illumination of only portions of the facets on a continuous area a retina of the eye is illuminated.

According to a second aspect, an optical element for a device for

Data entry provided, comprising a carrier, and a in the carrier

provided Fresnel element for directing light coupled in the carrier to an eye of an observer, wherein the Fresnel element has a plurality of facets, wherein at least a part of the facets of the Fresnel element may have a negative curvature, wherein the radius of curvature of the negative The curvature for each facet is at least twice as large as an average radius of curvature of an outside and an inside of the carrier. The average radius of curvature for the wearer may be determined by the radii of the wearer

in particular in a region in which light is guided by the carrier to the Fresnel element, and / or in a region in which the Fresnel element is located, are determined. The radius of curvature of the negative curvature for each facet may be at least twice as large as the average radius of curvature of the outside and inside of the carrier in the region in which light is guided by the carrier to the Fresnel element, and / or in the region in which the Fresnel element is located.

Such a configuration of the Fresnel element according to the first or second aspect, in particular, only a portion of the Fresnel element can be used without vignetting and still an entire retina are detected. The Fresnel element of the second aspect may be shaped in such a way that a coherent area on a retina of the eye can be illuminated by illumination only of partial areas of the facets. The Fresnel element of the first or second aspect may be shaped such that not all of the rays intersect between the Fresnel element and that of a retina of the eye at a point.

For at least a portion of the plurality of facets, the rays emanating from a respective facet may intersect at a point.

A passage point of rays emanating from the Fresnel element through a

Eye entry pupil of the eye can depend only on the location of the point of impact on one of the facets relative to the respective facet, and e.g. does not depend on the location of the point of impact relative to the entire Fresnel element.

The Fresnel element can be shaped such that by coupled into the carrier

Light rays each point of a desired area on a retina of the eye can be reached, without causing shading of the light rays through the Fresnel element.

The carrier may be a spectacle lens of a data glasses.

Furthermore, a device for data reflection is provided, comprising an optical element as described above, and a scanner device for providing an adjustably deflectable light beam for coupling into the optical element.

The scanner device may include a light source and a movable mirror.

The Fresnel element of the optical element can be set up in such a way that, by moving the light beam, each point of a target area on a retina of an eye can be reached without the light rays emanating from the scanner device being shaded by the Fresnel element.

The invention will be explained in more detail by means of embodiments with reference to the accompanying drawings. Show it: 1 shows a device for data reflection according to the prior art, FIG. 2 shows a further device for data reflection according to the prior art, FIG. 3 shows diagrams for explaining the effect of different beam diameters, FIG. 4 shows a further device according to the prior art, 5 is an enlarged view of a portion of the apparatus of Fig. 4,

6 is a partial view of a device according to an embodiment,

FIGS. 7A and 7B are diagrams for explaining optical elements according to FIG

Embodiments,

8 is a diagram for explaining the operation of some embodiments,

Fig. 9 is another diagram for explaining the operation of some

Embodiments,

10A and 10B are views of a device according to an embodiment,

1 1 A and 1 1 B views of a comparative example, and FIGS. 12A and 12B are views of a device according to another embodiment.

In the following, various embodiments will be explained in detail. These

Embodiments are merely illustrative and are not to be construed as limiting. In particular, a description of an embodiment with a plurality of features is not to be construed as meaning that all of these features are necessary to practice the particular embodiment. Rather, with others

In some embodiments, some of the illustrated features may be omitted and / or replaced by alternative features. Additionally or alternatively, other features or elements may be provided apart from those shown. Features of various embodiments may be combined with each other unless otherwise specified. For simplicity, identical or corresponding elements in the figures bear the same reference numerals. The exemplary embodiments described below relate in particular to a device for data reflection with a scanner device, ie a light source and a deflection device, as has already been described in detail in the introduction to the description. Elements of below described

Embodiments which have already been discussed in the introduction to the description bear the same reference numerals and will not be explained again in detail. In particular, embodiments relate to a particular embodiment of a Fresnel element that can replace, for example, the Fresnel element 40 of FIG. 4. Associated herewith, in embodiments, an activation of the deflection device 11 is such that only a part of the facets is taken into account for producing an image on a retina of an eye.

Fig. 6 shows a part of a device according to an embodiment. In particular, the device of FIG. 6 shows a spectacle lens 12 with a Fresnel element 60, which is designed according to an exemplary embodiment. The spectacle lens 12 together with the Fresnel element 60 together form an optical element according to a

Embodiment. Further illustrated by way of example are light rays 63, which may be obtained, for example, from a scanner device (not explicitly shown in Figure 6), e.g. as discussed in the introduction to the description and as shown in Figures 1, 2 and 4 (light source 10 and mirror 1) are generated. The light beams 63 illuminate only a partial area on one or more facets of the Fresnel element 60.

The facets of the Fresnel element 60 are designed in such a way that, despite the partial use of the facets, an entire desired area of the retina 16 of the eye is nevertheless continuously illuminated. In the embodiment of FIG. 6, this leads to the fact that there is no longer a single common point of intersection for all the beams. Rather, there are now two intersections 61, 62 for the ray paths of the two marked facets, in each of which only a part of the rays intersect. In other embodiments, more than two such intersection points may be present, for example an intersection of each used facet of the Fresnel element 60. In the embodiment of Fig. 6, the intersections 61, 62 are in front of the pupil 15 of the eye 14. In other embodiments also another position of the intersections 61, 62 possible. In particular, rays at the edge of each facet for illuminating the entire retina other than rays at the center of each facet of the Fresnel element 60 must be deflected. Some concrete implementation examples for such Fresnel elements will be explained later.

To illustrate this, FIGS. 7A and 7B show a ray path for a case where vignetting would be allowed (FIG. 7A) and a ray path as shown in FIG

Embodiments is used to avoid vignetting (Fig. 7B). Rays from different facets of a Fresnel element are labeled differently. In each case, the beam path between the Fresnel element (Fresnel surface, respectively at the top of the diagrams of Figures 7A and 7B) and the retina (bottom in Figures 7A and 7B) is shown. FIGS. 7A and 7B neglect for illustration the finite arrow height of the Fresnel element, the basic curvature of the element and the refractive power of the eye. As can be seen, in the case of FIG. 7A, all the rays intersect at one point, while in FIG. 7B there is an intersection point for each facet.

In such embodiments, therefore, each facet is a certain area of

Associated with the retina. This will be explained in more detail with reference to FIG. 8. FIG. 8 shows a part of a Fresnel element 40 from FIG. 4 or 60 from FIG. 6, in particular a region 84 of a facet 86. By means of this facet, a region 85 of the retina 16 is illuminated.

In the conventional Fresnel element 40, a beam which hits the facet 86 in the center of the region 84 is also directed to the center of the region 85 of the retina corresponding to a ray 80. A beam which strikes the edge of the facet 86 is also directed to the edge of the region 85 in accordance with a ray 82.

In contrast, in the Fresnel element 60 according to an exemplary embodiment, the left-hand part of the region 84 in FIG. 8 is not used. A beam which hits the center of the region 84 is therefore directed to the right edge of the region 85 in accordance with a marked ray 81. A ray of light striking the right edge of the region 84 is directed to the left edge of the region 85 corresponding to the ray 83 (which corresponds to the ray 82), so that overall the entire region 85 can be illuminated. FIG. 9 shows, in addition to the components already shown in FIG. 8, surface curves for the facet 86 both for the conventional case (eg Fresnel element 40) and for the case according to an exemplary embodiment (eg Fresnel element 60). A curve 91 indicates the course of the surface of a facet in an embodiment from the middle to the edge, while a curve 92 shows an example of a course of a conventional facet. At the right edge of the facet 86 (right-hand part of the curves 91, 92), the course is identical in the illustrated example, since the course of the beams 82, 83 is also substantially identical. In the middle (left-hand part of the curves 91, 92), however, the pitch differs significantly according to the different course of the light beams 80, 81. The dashed part between the solid parts of the curves 91, 92 schematically shows the connection of the surface slopes. Thus, in the conventional solution (curve 92), a convex shape of the facets tends to result, whereas in embodiments of the invention (curve 91), a concave shape tends to be in the optically used region of the facet, each viewed from one side, from which the rays to hit the facet.

The above convex and concave shapes are modified based on the local directional distribution of the rays incident on the Fresnel element from the light source, which changes the shape shown in the curves 91 and 92. This effect lies in the

Magnitude of the curvature, for example, the spectacle lens 12 of the preceding

Characters. However, the difference between the curvature according to the curve 91 and the curve 92 is greater than this effect.

In the following, with reference to Figures 10 and 12 are now concrete

Examples of embodiments of Fresnel elements explained. Fig. 1 1 shows a

Comparative example.

Figures 10A and 10B show an embodiment of a Fresnel element 100 whose base is a plane. That is to say, in this case, a base curvature of a carrier, for example a spectacle lens 101, is not taken into account in a basic curvature of the Fresnel element. Fig. 10B is an enlarged partial view of the embodiment of Fig. 10A. As can be seen, only one part of each facet of the Fresnel element 100 is used, which prevents vignetting and leads to a multiplicity of individual ray bundles. The following table indicates slopes and curvatures of the Fresnel element of Figs. 10A and 10B. The first line (facet number 1) corresponds to the facet, that of a nose of a User is closest in the case of data glasses, in the case of Figures 10A and 10B so the rightmost facet.

A positive curvature corresponds to a convex arrangement (dome), a negative one

Curvature of a bowl. The sign of the curvature here refers to the

Viewing from a side from which the rays hit the facet. FIGS. 1A and 1 1B show a comparative example of a Fresnel element 110 in a carrier 11 (eg a spectacle lens), wherein in each case a total area of the facets of the Fresnel element 110 is used. In particular, in the enlarged view of FIG. 11B, it can be seen that a significant proportion of the rays is vignetted and therefore would not be transmitted to the eye, or would only be transmitted to the eye to a great extent with reduced attenuation.

In the case that the bottom surface of the Fresnel element 10 is a plane (as in the Fresnel element 100 of Fig. 10), the curvature of the individual facets in the illustrated example is -0.01 19253542239191 mm ^-1 Thus, by a factor greater than 2 smaller than the curvature of the facets in the example of Fig. 10. Thus, here the embodiment is significantly "convex" than the comparative example.

FIGS. 12A and 12B show a further exemplary embodiment of a Fresnel element 120, which is arranged on a carrier 121, for example a spectacle lens. FIG. 12B again shows an enlarged view of FIG. 12A. In the case of Fig. 12, the bottom surface of the Fresnel element is a sphere, that is, the base curvature of the spectacle lens is in a base curvature of the Fresnel element. The slopes and bends of the

Facets of the Fresnel element 120 of FIG. 12 are given in the following table: Fresnel

Slope curvature [mm ^-1 ]

Element no.

1 0.6186428000366064 -0.03013769086033679

2 0.593778321 1209934 -0.02829216591286912

3 0.5699066335891513 -0.02669946640810734

4 0.5468785058999022 -0.02532952759859883

5 0.5245565207532827 -0.02415426712589405

6 0.5028179252428867 -0.02314560478997109

7 0.4815557452649128 -0.02227658558182128

In the case of the comparative example of Fig. 11, in the case where the base is a sphere, the curvature of each facet would be -0.007693623733758157 mm ^-1 The base curvature of the sphere in this example corresponds to -0.0078740157480315 mm ^-1 . Also in this case, the curvature of the embodiment of FIG. 12 is more than a factor of 2 larger than the curvature of the comparative example.

In particular, in some embodiments, the curvature may be negative and

amount to be at least twice as large as an average radius of curvature of the outside and inside of the glasses.

In the illustrated embodiments, the Fresnel element is shaped so that, although only a part of the facet are used, but can be achieved by a corresponding deflector each point of a target area on the retina, without causing shading. A field of view in the examples of Figs. 10-12 may be

For example, include a total angle of 20 degrees. The thickness of the carrier 101, 1 1 1 and 121 may be 7.5 mm.

The rays between Fresnel element and retina intersect as mentioned in some embodiments in more than one point. The passage point of the rays through the eye entrance pupil can essentially depend only on the location of the impact on a Fresnel facet relative to the Fresnel facet, but not on the location of the impact relative to the entire Fresnel element. The Fresnel element in the illustrated embodiments is shaped such that each facet is associated with an area of the retina, neighboring facets are associated with adjacent areas of the retina and the assignment on the retina has no gaps (ie the entire retina or an entire desired area of the retina can be continuously illuminated. Overlaps are possible in principle. In this case, only a part of each facet is used in the illustrated embodiments. The examples presented above are for illustrative purposes only and are not to be construed as limiting.

Claims

claims

1 . An optical element for a device for data input, comprising:

a support (12; 101; 121), and

a Fresnel element (60; 100; 120) provided in the support for directing light coupled into the support to an eye (14) of an observer,

wherein the Fresnel element (60; 100; 120) has a multiplicity of facets (86), wherein the Fresnel element (60; 100; 120) is shaped in such a way that only partial areas of the facets are illuminated by a continuous area on one Retina (16) of the eye (14) is illuminated.

2 Optical element for a device for data reflection, comprising:

a support (12; 101; 121), and

wherein the Fresnel element (60; 100; 120) has a plurality of facets (86), wherein at least a portion of the facets (86) of the Fresnel element may have a negative curvature, the curvature radius of the negative curvature being an absolute value for each facet is at least twice as large as an average radius of curvature of an outside and an inside of the carrier (12, 101, 121).

3. An optical element according to claim 2, wherein the Fresnel element (60; 100; 120) is shaped in such a way that via illumination only of partial areas of the facets

contiguous area on a retina (16) of the eye (14) is illuminated.

The optical element according to any one of claims 1 to 3, wherein the Fresnel element (60; 100; 120) is shaped such that not all of the rays are interposed between the Fresnel element (60; 100;

120) and that of a retina (16) of the eye (14) intersect at one point.

The optical element of claim 4, wherein for at least a portion of the plurality of facets (86), the rays emanating from a respective facet intersect at a point.

The optical element according to any one of claims 1 to 5, wherein the Fresnel element is formed to have a passage point from the Fresnel element (60; 100; 120).

outgoing rays through an eye entrance pupil (15) of the eye (14) in a given arrangement of the optical element to the eye entrance pupil (15) depends only on the location of the impact point on one of the facets (86) relative to the respective facet.

The optical element according to any one of claims 1 to 6, wherein the Fresnel element is shaped such that each point of a desired area on a retina (16) of the eye can be reached by light rays coupled into the support (12; 101; 121) without shading of the light rays by the Fresnel element (60; 100; 120).

The optical element according to any one of claims 1 to 7, wherein the support (12; 101; 121) is a spectacle lens of data glasses.

9. A device for data input, comprising:

an optical element according to any one of claims 1-8, and

a scanner device for providing an adjustably deflectable light beam for coupling into the optical element.

The apparatus of claim 9, wherein the scanner means comprises a light source (10) and a movable mirror.

1 1. Apparatus according to any one of claims 9 or 10, wherein the Fresnel element (60; 100; 120) of the optical element is arranged so that by moving the light beam any point of a target area on a retina (16) of an eye can be reached without the light rays emanating from the scanner device are shaded by the Fresnel element (60; 100; 120).