DE102020206451A1 - Optical arrangement of data glasses - Google Patents

Abstract

The invention relates to an optical arrangement (1) of data glasses (10), comprising an optical element (2) with a first hologram (21) and a second hologram (22), and a laser device (3) which is set up to produce visible light and to radiate infrared light onto the optical element (2), wherein the first hologram (21) is set up to deflect the visible light for projection onto a retina (101) of an eye (100) of a user, and wherein the second hologram ( 22) is set up to deflect the infrared light in order to irradiate the outside of the eye (102) of the eye (100) of the user.

Description

State of the art

The present invention relates to an optical arrangement of data glasses and data glasses.

The use of oculography (also: eye tracking) is known in data glasses which are provided for image projection, for example onto a retina of the user. The oculography is used, for example, to adapt a control of a projection unit of the data glasses when displaying context-sensitive information. US 7,637,615 B2 shows such data glasses with retina projection and eye tracking based on prism mirrors. Such data glasses often have a complex and expensive construction.

Disclosure of the invention

In contrast, the optical arrangement of data glasses according to the invention with the features of claim 1 is characterized by a low system complexity and a small amount of space required. This is achieved by an optical arrangement comprising an optical element with a first hologram and with a second hologram, and a laser device which is set up to radiate visible light and infrared light onto the optical element. The first hologram is set up to deflect the visible light in order to achieve a projection on a retina of a user's eye. The second hologram is set up to deflect the infrared light in order to irradiate the outside of the eye of the user with the infrared light.

The first hologram is thus provided in order to direct the visible light provided for an image display on the retina, that is to say for a so-called retina projection, directly onto the retina of the user's eye. The visible light preferably carries image information which is projected onto the retina. In particular, the visible light is deflected, and in particular bundled, by the first hologram in such a way that the deflected light beam can pass completely or essentially completely through a pupil of the eye.

The second hologram is also provided in order to direct the infrared light provided for eye tracking onto the outside of the eye. The infrared light is preferably deflected by the second hologram in such a way that the deflected light beam essentially covers the entire outside of the eye. It is particularly advantageous if the deflected light beam irradiates the entire eye socket, including the eyelids and caruncle, of infrared light.

In other words, the optical arrangement for the two functions of retina projection and gaze tracking comprises a common laser device which emits the light required for the two functions, that is, both the visible light and the infrared light. The corresponding deflection of visible and infrared light takes place through the two holograms of the optical element. In particular, the holograms each form different, holographic grating structures in the optical element, which each cause a deflection of the corresponding light. Preferably, the two holograms are each partially or completely transparent to the other light. The first hologram is thus preferably partially or completely transparent to the infrared light and the second hologram is partially or completely transparent to the visible light.

The holograms make it possible in a particularly simple and also inexpensive manner to deflect the light optimally for the respective function, the light beams incident on the holograms being emitted from a single, common light source. As a result, a low system complexity and little installation space for the required components of the optical system can be achieved in a particularly advantageous manner. Above all, this enables the user to have a particularly large unobstructed field of vision which, in particular, is not restricted by a large number of components.

The laser device can preferably have a plurality of laser emitters for generating the visible light and the infrared light. For example, the laser emitter for the visible light can in turn have a plurality of individual laser emitters, preferably each for red, green and blue light, that is to say so-called RGB laser emitters. The infrared laser emitter is particularly preferably an edge-emitting or surface-emitting semiconductor laser. The infrared laser emitter is preferably set up to emit infrared light in a wavelength range from 780-1000 nm, particularly preferably from 830-940 nm.

The subclaims contain preferred developments of the invention.

The optical element preferably has a single-layer holographic film in which the first hologram and the second hologram are formed. That is, the first hologram and the second hologram are exposed together in a single layer. Preferably the holographic film comprises a photopolymer. For example In addition to the holographic film, the optical element can also have a carrier film on which the photopolymer is held. As a result, the optical element can be manufactured in a particularly cost-effective manner with little material.

The optical element particularly preferably has a first holographic film in which the first hologram is formed, and a second holographic film in which the second hologram is formed. The optical element is thus designed in particular with two layers and has two holographic films, which are preferably connected to one another. The two holographic films preferably each have a photopolymer in which the corresponding hologram is formed. The two holographic films are preferably connected to one another by means of an adhesive layer, so that the adhesive layer is arranged in particular between the two holographic films. The adhesive layer can preferably have the same material as the photopolymer. Alternatively, the two holographic films can be arranged directly adjacent to one another. Due to the material properties of the photopolymer, the two holographic films can be joined to one another during the generation of the holograms in such a way that the holographic films have an adhesive effect on one another and thus stick to one another by themselves. A double-layer optical element, each with one hologram per layer, enables a particularly high precision of the optical element to be achieved with simple and inexpensive manufacture. In particular, due to the fact that the two holograms can be manufactured separately, each of the holograms can be generated with optimal optical properties without, for example, being influenced by the other hologram in each case. A particularly high optical precision of the optical element can thereby be achieved.

The second hologram is preferably set up to direct the infrared light in the form of parallel and / or diverging and / or converging light beams onto the outside of the eye. It should be noted that the entire light beam should run convergent and / or divergent and / or parallel to the eye. For example, the divergence of the individual rays contained in the bundle can be independent of the divergence of the bundle of rays. Diverging light rays are considered to be light rays which, proceeding from the optical element and expand in a propagating manner in the direction of the outside of the eye. In this case, the second hologram preferably has a negative refractive power, for example such that a focal point of the deflected light rays is located on a side of the optical element opposite the eye. Light rays which are bundled by the optical element towards the outside of the eye are regarded as converging light rays. In this case, the second hologram preferably has a positive refractive power, for example such that a focal point of the deflected infrared light rays is located on that side of the optical element on which the eye is also located. In order to direct parallel light beams onto the eye, the second hologram can, for example, have a refractive power of zero, that is to say an infinite focal length. Depending on the intended use, in particular depending on the interpupillary distance, the second hologram can thus be optimally adapted in order to irradiate the outside of the eye as completely as possible with the infrared light. The second hologram can preferably have different refractive powers, that is to say in particular astigmatic properties.

The optical arrangement further preferably further comprises a deflection device which is set up to deflect the visible light emitted by the laser device and also the infrared light onto the optical element. The deflecting device is preferably a mirror. By directing the visible and infrared light emitted by the laser device onto the optical element, that is to say onto the two holograms, by means of the deflecting device, a particularly flexible and space-saving arrangement of the components of the optical arrangement can be made possible.

The deflecting device preferably has a micromirror actuator which is set up to scan the visible light and the infrared light via the optical element, that is to say in particular via the two holograms. The micromirror actuator is preferably set up to scan the visible light and the infrared light over the optical element along at least two axes, which preferably each lie in a plane of the optical element, and in particular perpendicular to one another. For example, the micromirror actuator can be a MEMS-actuated micromirror. The micromirror actuator can preferably be operated resonantly in at least one axis. Advantageously, this resonantly operated axis of the micromirror actuator can oscillate at frequencies of 10 kHz to 60 kHz. Furthermore, the micromirror actuator can preferably be operated in one axis at a frequency lower than the resonance frequency. This axis of the micromirror actuator, which is operated in a non-resonant manner, can advantageously oscillate at frequencies of 60 Hz to 300 Hz. The micromirror actuator offers a particularly simple and inexpensive way of generating particularly precise light signals by means of a simple laser device and directing them onto the optical element.

Particularly preferably, at least one of the two holograms, preferably the second hologram, has locally different refractive powers. The corresponding hologram is designed in such a way that the locally different refractive powers are designed as a function of a local beam speed of the light beams scanned via the optical element. A speed of the light beam scanned by means of the micromirror actuator over the optical element in a plane of the optical element, that is to say a speed at which the light beam moves along one of the axes, is regarded as the local beam speed. Since the scanned light beam is particularly scanned line-by-line resonantly across the optical element, that is to say moves back and forth at high frequency in the plane of the optical element, the local beam speed varies significantly in an area of extent of the optical element. In particular, the local beam velocity at the edge of a scan area is significantly lower than in a center of the scan area, which can result, for example, in a lower density of scan points in the center of the scan area and an excessively high density of scan points in the edge area. By adapting the local refractive powers of the hologram, in particular the second hologram, to these locally different beam speeds, a distribution of the scanning points resulting on the eye when scanning the light rays via the optical element can be adapted, in particular so that the scanning points are particularly uniform, for example across the Eyes outside, to be distributed. Alternatively, the scanning points can also be increased in a center of the outside of the eye in order to have a particularly high optical resolution in this area when tracking the eyes. For example, the hologram can have a refractive power of zero, that is, an infinite focal length, so that the deflected light beams are parallel, where the local speed of the laser beam scanned via the optical element corresponds to its mean speed. Thus, the adaptation of the locally different refractive powers, particularly in the case of the second hologram, offers the advantage of optimized resolution and thus a particularly high level of accuracy in gaze tracking.

The at least one hologram, preferably the second hologram, preferably has a smaller refractive power in an edge region of an extension surface over which the hologram extends than in a central region of the extension surface. This means that the hologram has a greater refractive power in the central area than in the edge area which surrounds the central area. For example, a high positive refractive power can be present in the central area, with a smaller positive refractive power, or a refractive power of zero, or a negative refractive power preferably being present in the edge region. There is preferably a continuous transition in the refractive power. Alternatively, two areas of the hologram with different refractive powers can also be provided for particularly simple production. A local refractive power, which is smaller at the edge than in the center, makes it possible in a particularly simple and effective manner to compensate for the different sampling rates which can occur as a result of scanning by means of the micromirror actuator.

The second hologram is further preferably designed in such a way that infrared light rays impinging on the second hologram in an edge region of a scan region are directed to an eye center on the outside of the eye. A center of the visible area of the surface of the eye is regarded as the “center of the eye on the outside of the eye”. Infrared light rays impinging in the center of the scan area are directed onto an area of the edge of the eye on the outside of the eye that surrounds the center of the eye. An area in the plane of the optical element within which the infrared light is scanned via the optical element by means of the micromirror actuator is regarded as the scanning area. Preferably, an area of the edge area is at least 30%, preferably a maximum of 60%, of a total area of the scan area. In other words, the second hologram is designed in such a way that the deflected infrared light beams, that is to say the light beams propagating from the second hologram to the eye, overlap. The deflected light beams preferably overlap in such a way that light beams emanating from the edge area of the scan area are directed onto the center of the eye and that the light beams emanating from the center of the scan area are directed onto the eye edge area. As a result, the locally different density of the scanning points in the scan area can be used particularly easily in order to obtain a high resolution at the desired locations, that is to say in the center of the eye, as a result of which a particularly high level of accuracy can be achieved when tracking the gaze.

The optical arrangement particularly preferably further comprises a detector which is set up in particular to detect infrared light scattered back from the outside of the eye. The detector preferably comprises an evaluation device by means of which a signal generated by the detector based on the detection of the backscattered infrared light can be evaluated.

The detector preferably comprises a photodiode, by means of which the infrared light scattered back from the outside of the eye is detected can. A photodiode offers a particularly simple and inexpensive way of detecting the backscattered infrared light in order to be able to determine a viewing direction.

The detector advantageously comprises two photodiodes, which are preferably arranged next to one another, each with a laser line filter. The two laser line filters of the photodiodes preferably have transmission wavelengths that are 5 nm to 20 nm different. This means that the two laser line filters are preferably separated from one another by 5 nm to 20 nm, particularly preferably 10 nm. In particular, one of the two laser line filters is precisely matched to the wavelength of the infrared light emitted by the laser device, that is to say has a transmission wavelength that corresponds to the wavelength of the emitted infrared light. The other laser line filter is preferably shifted in wavelength by a few nanometers so that, for example, an interference signal can be determined by means of a differential signal of the two photodiodes calculated in the detector and an interference-compensated input variable can be used for gaze tracking.

The detector preferably has a filter device for filtering the light incident on the detector. The filter device can be designed in many ways, for example it can also be integrated in a signal processing of the signal generated by the detector. In particular, an evaluation of the infrared light scattered back from the second hologram and detected by the detector can thereby be optimized for particularly precise eye tracking.

The filter device advantageously comprises a long-pass filter and / or a band-pass filter and / or a laser line filter which is designed exclusively for the transmission of infrared light, in particular with a wavelength which corresponds to the wavelength of the infrared light which is emitted by the laser device. The long-pass filter and / or laser line filter is preferably arranged between the optical element and the detector, for example a photodiode of the detector. As a result, particularly precise filtering of the infrared light to be detected by the detector can already be carried out on the hardware side.

Furthermore, the invention leads to data glasses which comprise the optical arrangement described above. The optical element of the optical arrangement is preferably embedded in a spectacle lens of the data glasses. For example, the optical element with the two holograms can be attached to one side of the spectacle lens, in particular by means of an adhesive connection, which enables the data glasses to be manufactured in a particularly simple manner. Alternatively, the optical element can, for example, be cast into the spectacle lens when the spectacle lens is manufactured, so that the optical element is completely surrounded by the spectacle lens after manufacture. The laser device can, for example, be integrated into a temple of the data glasses. Furthermore, for example, a micromirror actuator can be integrated into the temple of the data glasses. This results in a particularly simple and compact construction of the data source, which is characterized by few and compact components and can thus offer a high level of comfort for the user to carry and operate.

Figure list

• 1 eine vereinfachte schematische Ansicht einer Datenbrille mit einer optischen Anordnung gemäß einem ersten Ausführungsbeispiel der Erfindung,
• 2 die optische Anordnung der 1 im Detail,
• 3 eine Detailansicht einer optischen Anordnung gemäß einem zweiten Ausführungsbeispiel der Erfindung, und
• 4 eine Detailansicht eines optischen Elements einer optischen Anordnung gemäß einem dritten Ausführungsbeispiel der Erfindung.

The invention is described below using exemplary embodiments in conjunction with the figures. In the figures, functionally identical components are each identified by the same reference symbols. It shows:

• 1 a simplified schematic view of data glasses with an optical arrangement according to a first embodiment of the invention,
• 2 the optical arrangement of the 1 in detail,
• 3 a detailed view of an optical arrangement according to a second embodiment of the invention, and
• 4th a detailed view of an optical element of an optical arrangement according to a third embodiment of the invention.

Preferred embodiments of the invention

1 shows a simplified schematic view of data glasses 10 according to a first embodiment of the invention. The data glasses 10 includes a lens 11 and a hanger 12th . The data glasses 10 is intended to be worn on a head of a user.

The data glasses 10 includes an optical assembly 1 , by means of which a retina projection and gaze tracking on one eye 100 of the user can be performed at the same time.

The optical arrangement 1 (see also 2 ) includes a laser device 3 which is set up to emit visible light and infrared light. The visible light is intended to convey image information directly onto a retina 101 of the eye 100 of the user to project. The outside of the eye is created by means of the infrared light 102 of the eye 100 of the user irradiated.

In addition, the optical arrangement includes 2 a detector 5 with two photodiodes arranged next to each other 51 , 52 for capturing from the outside of the eye 102 backscattered infrared light. The detector 5 can comprise an evaluation unit which is set up by the photodiodes 51 , 52 to evaluate detected infrared light in order to determine the current line of sight of the eye 100 to investigate. For a particularly precise determination, the detector 5 also a filter device, for example with one laser line filter per photodiode 51 , 52 , wherein the filter device is provided which is directed to the photodiodes 51 , 52 filter incident light.

The laser device 3 is on the hanger 12th the data glasses 10 arranged and aligned so that the emitted light is essentially parallel to the bracket 12th and towards the eye 100 is sent out.

The optical arrangement also includes 1 a deflection device 4th with a micromirror actuator 45 which is set up by the laser device 3 Redirect emitted light and through a into the lens 11 embedded optical element 2 to scan. This is done by the micromirror actuator 45 deflected visible and infrared light along two axes x, y via the optical element 2 scanned. The micromirror actuator 45 is operated resonantly in at least one axis.

The optical element 2 has a first hologram 21 and a second hologram 22nd on. The two holograms 21 , 22nd are together in a single-layer holographic film 20th trained (see 2 ).

The two holograms 21 , 22nd are designed to be able to implement the two functions of retina projection and gaze tracking. In detail is the first hologram 21 set up to redirect the visible light, the first being a hologram 21 is transparent to the infrared light. Furthermore, the second is the hologram 22nd set up to redirect the infrared light, the second hologram 22nd is transparent to visible light.

A power of the first hologram 21 is designed so that the first hologram 21 deflected light rays 27 of visible light completely through a pupil 103 of the eye can pass through to the retina 101 to be able to project an image. A power of the second hologram 22nd is, however, designed so that the second hologram 22nd deflected light rays 28 of the infrared light essentially parallel from the optical element 2 towards the eye 100 are radiated and essentially completely to the optical element 2 turned outside of the eyes 102 of the eye 100 irradiate.

Advantage of the two holograms 21 , 22nd which are each for the two functions of the smart glasses 10 To achieve different deflections of the visible or infrared light is that a particularly simple and compact construction of the data glasses 10 can be provided. In particular, few and compact components are required here, so that the data glasses can offer the user a high level of wearing comfort and ease of use. In particular, the necessary components can be arranged in such a way that the user's field of vision is not unnecessarily restricted.

Furthermore, the two offer holograms 21 , 22nd the advantage that in each case a deflection of the corresponding light beams that is optimally matched to the intended use can be implemented.

A particularly favorable further training shows the 3 showing a detailed view of an optical arrangement 1 shows according to a second embodiment of the invention. The second exemplary embodiment essentially corresponds to the first exemplary embodiment with the difference that the second hologram 22nd of the optical element 2 is designed differently.

In the second exemplary embodiment, the second hologram 22nd over its extension area 25th varying focal lengths or refractive powers. The second is a hologram 22nd designed so that within an edge region 40a a scan area 40 on the second hologram 22nd incident infrared light rays on an eye center 102b the outside of the eyes 102 of the eye 100 are directed. Central in the scan area 40 , so in a central area 40b , on the second hologram 22nd Infrared light rays that strike one are thereby directed towards the center of the eye 102b surrounding eye rim area 102a the outside of the eyes 102 of the eye 100 directed. For this purpose, there is a refractive power of the second hologram 22nd at the edge 40a larger than in the central area 40b . This enables non-linear effects of the micromirror actuator in a simple and effective manner 45 are compensated, so that one due to the resonant operation at the edge area 40a present high density of sample points when scanning is used to the eye center 102b to be able to scan with a high resolution. In this way, a particularly high level of precision can be achieved in eye tracking.

the 4th shows a detailed view of an optical element 2 an optical arrangement 1 according to a third embodiment of the invention. The third exemplary embodiment corresponds essentially to the first exemplary embodiment from FIG 1 and 2 with the difference that the two holograms 21 , 22nd are not formed in a common layer, but in separate layers.

The optical element 2 of the third embodiment includes a first holographic film 20a in which the first hologram 21 and a second holographic film 20b , in which the second hologram 22nd is trained. The two holographic films 20a , 20b can by means of an adhesive layer 20c be connected to each other. The composite of the two holographic films 20a , 20b is in the lens 12th embedded, that is, on both sides of a part of the lens 12th surround. For example, the holographic films 20a , 20b be arranged on a (not shown) carrier layer, which is in the finished optical element 2 for example between the material of the spectacle lens 12th and the holographic films 20a , 20b can be located.

In the third embodiment shown, the second is holographic film 20b doing it on one of the eye 100 facing side arranged. That is, that from the laser device 3 Irradiated visible and infrared light, characterized by an irradiation direction A, hits the second hologram first 22nd in the second holographic film 20b . Alternatively, the two holographic films 20a , 20b however, it can also be arranged the other way around, so that the first holographic film 20a with the first hologram 21 closer to the eye 100 than the second holographic 20b with the second hologram 22nd lies.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 7637615 B2 [0002]

Claims (15)

Optical arrangement of data glasses (10), comprising: - An optical element (2) with a first hologram (21) and a second hologram (22), and - a laser device (3) which is set up to radiate visible light and infrared light onto the optical element (2), - the first hologram (21) being set up to deflect the visible light for projection onto a retina (101) of an eye (100) of a user, and - wherein the second hologram (22) is set up to deflect the infrared light for irradiating an outer side (102) of the eye (100) of the user. Optical arrangement according to Claim 1 wherein the optical element (2) comprises a single-layer holographic film (20) in which the first hologram (21) and the second hologram (22) are formed. Optical arrangement according to Claim 1 wherein the optical element (2) comprises a first holographic film (20a) in which the first hologram (21) is formed, and a second holographic film (20b) in which the second hologram (22) is formed. Optical arrangement according to one of the preceding claims, wherein the second hologram (22) is set up to direct the infrared light in the form of parallel and / or diverging and / or converging light rays onto the outside of the eye (102). Optical arrangement according to one of the preceding claims, further comprising a deflection device (4) which is set up to deflect the visible light and infrared light emitted by the laser device (3) onto the optical element (2). Optical arrangement according to Claim 5 wherein the deflecting device (4) has a micromirror actuator (45) which is set up to scan the visible light and the infrared light, in particular along at least two axes, via the optical element (2). Optical arrangement according to Claim 6 , wherein at least one of the two holograms (21, 22), preferably the second hologram (22), has locally different refractive powers, which are formed as a function of a local beam speed of the light beams scanned via the optical element (2). Optical arrangement according to Claim 7 wherein the at least one hologram (21, 22), preferably the second hologram (22), has a smaller or greater refractive power in an edge region (40a) of an extension surface (25) than in a central region (40b) of the extension surface (25) . Optical arrangement according to one of the Claims 6 until 8th , wherein the second hologram (22) is designed such that in an edge region (40a) of a scan region (40) incident on the second hologram (22) infrared light rays are directed to an eye center (102b) of the eye (100), and that infrared light rays impinging centrally in the scanning area (40) are directed onto a peripheral area (102a) of the eye (100) surrounding the center of the eye (102b). Optical arrangement according to one of the preceding claims, further comprising a detector (5) for detecting infrared light scattered back from the outside of the eye (102). Optical arrangement according to Claim 10 , wherein the detector (5) comprises a photodiode (51). Optical arrangement according to Claim 11 , the detector (5) having two photodiodes (51, 52) each with a laser line filter, the two laser line filters in particular having different transmission wavelengths by 5 nm to 20 nm. Optical arrangement according to one of the Claims 10 until 12th , wherein the detector (5) has a filter device for filtering the light incident on the detector (5). Optical arrangement according to Claim 13 , wherein the filter device has a long-pass filter and / or a band-pass filter and / or a laser line filter which is designed exclusively for the transmission of infrared light. Data glasses, comprising an optical arrangement (1) according to one of the preceding claims, in particular wherein the optical element (2) is embedded in a spectacle lens (11) of the data glasses (10).

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