Method for operating a pair of smart glasses

Abstract

The invention relates to a method for operating smart glasses (50), the smart glasses (50) comprising an input unit and / or an output unit (7) and a gaze detection device (20), wherein the gaze detection device (20) detects any eye movement of an eye (10), the method comprising the following steps: irradiating at least one wavelength modulated laser beam (1) to the eye (10); detecting the optical path length (2) of the emitted laser beam (1) based on laser feedback interferometry of the emitted laser radiation with radiation backscattered from the eye (10); detecting a Doppler shift of the emitted and backscattered radiation based on laser feedback interferometry; and detecting eye velocity based on the Doppler shift, and wherein the input unit and / or the output unit (7) is operated based on the optical path length (2) and / or the eye velocity.

Description

Technical Field

[0001] The present invention relates to a method for operating smart glasses and the smart glasses. Background Art

[0002] It is known to use eye tracking or eye detection (also known as oculography) to determine eye movements and estimate gaze direction. It is also known to use smart glasses to project images, for example, onto the retina of a user. For example, gaze detection is used to adjust the control means of a projection unit of a pair of smart glasses, for example when displaying environmentally sensitive information. US 7,637,615 B2 discloses such smart glasses using retinal projection and prism-based eye tracking. Known systems for eye tracking are generally based on detecting information about the position of the eye using camera-based systems or electrical or electromagnetic sensors in the area of ​​the eye. In addition, scanning laser systems are known, for example, which use micromirrors to scan a laser spot on the eye. All of these systems are generally of high complexity and energy consumption, often with limited temporal resolution. Summary of the invention

[0003] In contrast, the method according to the invention with the features of claim 1 is characterized by a particularly energy-efficient and cost-effective method of operating a pair of smart glasses with a high user convenience. This is achieved by a method for operating a pair of smart glasses, the pair of smart glasses comprising an input unit and / or an output unit and a gaze detection device. The gaze detection device is used to determine eye movements using the following steps:

[0004] irradiating the eye with at least one wavelength modulated laser beam,

[0005] Detection of the optical path length of the emitted laser beam based on laser feedback interferometry of the emitted laser beam and the radiation backscattered from the eye,

[0006] Based on laser feedback interferometry, the Doppler shift of the emitted and backscattered radiation, in particular the Doppler shift between their frequencies, is detected, and

[0007] Detect eye velocity based on Doppler shift,

[0008] Therein, the input unit and / or the output unit operates based on the optical path length and / or the eye velocity.

[0009] Eye movement is considered to be any movement of the eye, in particular relative to the head of the user of the smart glasses. In particular, such eye movement corresponds to a change in the viewing direction of the eye. Furthermore, the eye movement preferably corresponds to a rotation of the eye (in particular the eyeball) within the eye socket.

[0010] In other words, in the eye movement determination, a wavelength-modulated laser beam, in particular emitted from a wavelength-modulated laser source, is irradiated onto the eye of the user. The laser beam is at least partially backscattered at the surface of the eye. The backscattered radiation is a portion of the radiation scattered at the surface of the eye which is parallel to the emitted laser beam and can therefore interfere with it. The backscattered portion interferes with the incident laser radiation, i.e. with the laser radiation propagating towards the eye. The backscattered portion of the irradiated laser beam may also be referred to as backscattered radiation. By so-called laser feedback interferometry, an overlap of the emitted laser beam and the backscattered radiation is produced, so that there is interference radiation produced thereby. This produced interference radiation can be detected and analyzed, for example, with the aid of a detector.

[0011] Laser feedback interferometry is considered to be the detection and analysis of the overlap of an irradiated laser beam and its backscattered parts, i.e. the detection and analysis of the generated interference radiation. Based on laser feedback interferometry, the optical path length of the emitted laser beam is determined. The optical path length is considered to be the product of the geometric distance from the laser source to the surface of the eye covered by the emitted laser beam and the refractive index of the material present there. This means that if the laser beam is emitted from the laser source directly towards the eye in air (refractive index of about 1), the optical path length approximates the distance between the laser source and the eye very well. For example, if the wavelength of the emitted laser radiation is known, the optical path length can be estimated based on constructive or destructive interference.

[0012] Preferably, the triangle wave modulated laser light is emitted as a wavelength modulated laser beam within a wavelength range. The optical path length can be determined by analyzing the interferometrically emitted and backscattered radiation, in particular by calculating the average value of the resulting interference frequency relative to the two edges of the triangle wave modulated signal.

[0013] Furthermore, if there is a movement of the eye relative to the scattered laser radiation, a Doppler shift occurs, in particular between the frequency of the emitted radiation and the frequency of the backscattered radiation due to the Doppler effect. With the aid of laser feedback interferometry, this Doppler shift can be detected. The Doppler shift can then be used to determine the eye velocity. The eye velocity is considered to be the tangential velocity at a point on the eye surface, which corresponds to the point at which the laser radiation impinges on the eye surface. Preferably, the eye velocity comprises the absolute value of the current velocity as well as the direction of the current velocity.

[0014] The input unit and / or the output unit are then operated based on the determined optical path length and / or eye velocity. The method thus allows the input unit and / or the output unit to be operated in a particularly simple and efficient manner by the eye movements of the user. The use of laser feedback interferometry, in particular the specific method of detecting eye movements using the Doppler effect, has the advantage of a particularly high temporal sampling rate, whereby eye movements can be detected with a particularly high temporal resolution. In addition, the method offers the advantage of using simple and inexpensive components and evaluation algorithms with lower energy requirements. In particular, no computationally intensive image data processing is required. In addition, advantageously, no moving parts such as scanning devices will be required, thus providing a particularly flexible and robust applicability.

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

[0016] Preferably, the input unit and / or the output unit is activated or deactivated based on the optical path length and / or the eye velocity. That is, the eye tracking device is able to initiate activation and / or deactivation of the input unit and / or the output unit. Preferably, the deactivated state is a state in which no energy is consumed by the input unit and / or the output unit. Thus, a particularly energy-efficient operation of the smart glasses can be provided, since power supply of the gaze detection device is only required when no input from the user and / or no output to the user is required.

[0017] Particularly preferably, the gaze detection device directs a single laser beam to the eye, wherein, based on the detected optical path length, a detection is performed when the gaze direction of the eye is aligned so that the single laser beam enters the eye through the pupil. A part of the input unit and / or the output unit and / or the eye tracking device is operated based on the detection of the single laser beam entering the eye. For example, the eye tracking device can therefore be set to a sleep mode with reduced energy consumption. Preferably, in this sleep mode, only a single laser beam is directed to the eye. By any corresponding eye movement of the user, so that the laser beam enters the eye through the pupil, corresponding to looking in a specific direction, for example downward in the user's field of view, the input unit and / or the output unit and / or the eye tracking device can be operated and, for example, can be fully activated. Preferably, the individual laser beams can be designed to be visible to the user during the process, so that the user receives corresponding optical feedback when operating. This can enable the smart glasses to be operated particularly power-saving and user-friendly.

[0018] Preferably, the eye gesture is recognized based on the optical path length and / or the eye velocity. The input unit and / or the output unit will operate based on the recognized predetermined eye gesture. The eye gesture can, for example, be any predetermined movement pattern of the eye, such as a downward turn followed by a sideways turn. In particular, different actions can be performed based on different predetermined eye gestures. In particular, it may be sufficient to determine the relative eye movement by means of an eye tracking device, wherein for example the predetermined eye gestures can be clearly distinguished without determining the absolute eye position. Therefore, a specific high-resolution and energy-efficient detection of eye movements using an eye tracking device can enable a particularly efficient and reliable operation of the smart glasses.

[0019] Preferably, the input unit and / or the output unit comprises an image projection unit arranged to project the image onto the retina of the eye.By operating the image projection unit using an eye tracking device, a particularly convenient and precise image projection may be provided.

[0020] Preferably, image parameters of the image projected by the image projection unit are adjusted based on the determined optical path length and / or eye velocity. This allows the image visible to the user to have a particularly high image quality, wherein a specific adjustment of the image parameters means that, for example, areas in which a lower image quality is sufficient for anatomical reasons can be displayed with little display effort, thereby obtaining a particularly efficient operation of the smart glasses.

[0021] Particularly preferably, the image sharpness and / or image resolution and / or brightness and / or color distribution of the image projected by the image projection unit is adjusted. Preferably, these image parameters are adapted over the entire field of view of the user corresponding to the instantaneous viewing angle of the eye. Advantageously, the image parameters are adjusted according to the position of the fovea of ​​the eye, which corresponds to the sharpest visual area. In particular, the image projected by the image projection unit is adjusted so that in the area of ​​the fovea there is a higher image sharpness and / or a higher image resolution than in the surrounding areas of the visual field. Particularly preferably, the image sharpness and / or image resolution decreases radially outwards in the visual field of the user, in particular continuously. This enables efficient operation of the smart glasses, since a lower display quality of the image projection unit can be achieved in areas in which the visual ability is declared in less detail for anatomical reasons. This results in a lower computational effort and a lower energy consumption in the image projection unit.

[0022] Preferably, the method further comprises the following steps: detecting the maximum eye velocity during the eye movement and predicting the eye movement end position based on the maximum eye velocity. Thereby, the operation of the input unit and / or the output unit is performed based on the eye movement end position. Particularly preferably, the adjustment of the image parameters of the image projected by the image projection unit is performed based on the eye movement end position. Therefore, in particular, it can be predicted at which position the eye movement stops in the case of a rapid eye movement (i.e., a so-called saccade). Preferably, the prediction of the eye movement end position is based on the assumption that the eye performs a uniformly accelerated movement during such an eye movement. That is, there is a constant positive acceleration during the first half of such an eye movement, while a constant (especially of the same magnitude) negative acceleration is generated during the second half of the eye movement. By detecting the first half of the corresponding speed curve, i.e., the speed of the eye movement from rest to the maximum speed during the movement, the second half of the speed curve can be estimated, in particular based on the assumption of mirror symmetry. In this way, in particular by integrating the determined speed curve, the end point of the eye movement can be estimated. Preferably, the maximum speed during the eye movement is determined based on the detection of a reduced eye speed following an increase in the eye speed. In particular, if image parameter adjustment occurs to adapt to the predicted eye movement end position, any delay in adjusting image parameters in response to a change in the user's gaze can advantageously be avoided, so that a very precise and optimally adapted display of the projected image can always be ensured.

[0023] Particularly preferably, the input unit and / or the output unit comprises a sound reproduction unit and / or an electronic user device. The electronic user device is preferably provided as a separate device connectable to the smart glasses, for example using a wireless connection. This enables a particularly flexible use of the smart glasses.

[0024] Preferably, eyelid closure of an eye is detected based on the optical path length and / or eye velocity. This means that in particular any blinking can be detected. In this case, the determined eye velocity is the speed of eyelid closure. In particular, eyelid closure can be determined based on a characteristic velocity and preferably a characteristic direction of the velocity determined using an eye tracking device. Preferably, the detection of eyelid closure can be used to operate an input unit and / or an output unit. For example, any specific action can be performed using a predetermined blinking pattern or by closing the eyelids for a predetermined time period. Furthermore, the detection of eyelid closure of an eye can be used for fatigue detection. Therefore, a particularly wide range of applications of smart glasses can be provided.

[0025] Preferably, at least part of the eye tracking device is always active. Thus, for example, a specific eye gesture can be performed at any time to operate, in particular activate, an input unit and / or an output unit, which would otherwise be switched off. As a result, the input unit and / or the output unit can be operated as required, so that the energy consumption of the smart glasses over their entire operating time is particularly low. Due to the particularly energy-efficient gaze detection method, it can be operated all the time, for example without the high energy consumption of the smart glasses.

[0026] Preferably, the method further comprises the step of detecting the reflectivity of the eye based on the amplitude and phase of the radiation backscattered by the eye, thereby operating the input unit and / or the output unit based on the reflectivity. Preferably, this reflectivity-based operation can also be performed instead of or in addition to the operation based on the optical path length and / or the eye velocity. It is particularly advantageous if the image projection unit is operated based on the determined optical path length and / or the eye velocity and / or based on the reflectivity, in particular wherein image parameters of the image projected by the image projection unit are adjusted based on the determined optical path length and / or the eye velocity and / or based on the reflectivity. In this context, reflectivity refers in particular to the complex reflectivity with the amplitude and the phase of the radiation backscattered by the eye. By additionally measuring the reflectivity of the eye, the current position of the eye can therefore be determined particularly accurately. Advantageously, based on the different reflectivities of different parts of the eye, it can be identified which part of the eye the laser beam currently irradiates, for example, and any absolute eye position can be estimated therefrom. For example, when the laser radiation impinges on different parts of the eye, the reflectivities can be significantly different and can differ in characteristics. For example, significantly stronger scattering occurs when the laser radiation hits the iris of the eye and passes through the cornea compared to the irradiation of the retina. Preferably, the determination of the reflectivity can therefore be used to determine when the laser beam, which is in particular stationary relative to the user's head, moves past anatomical boundaries during an eye movement. In this way, any eye movement can be determined particularly easily and precisely, for example as a trigger for operating an input unit and / or an output unit.

[0027] Furthermore, the invention provides that the smart glasses comprise an input unit and / or an output unit and a gaze detection device. The input unit and / or the output unit are arranged to receive input from a user and / or provide output to a user. The gaze detection device comprises a laser device and a control device, the laser device being arranged to irradiate at least one laser beam onto the eye, the control device being arranged to operate the laser device. The smart glasses are configured to perform the above method. The smart glasses are characterized by a particularly simple and inexpensive configuration having a high eye movement detection rate and a low energy requirement.

[0028] Preferably, the laser device comprises at least one surface emitter (also called: vertical cavity surface emitting laser, or VCSEL for short) with a photodiode integrated therein. Such a laser device can be used for detecting eye movements based on laser feedback interferometry with an eye tracking device of a particularly simple, compact and cost-effective design. Such a laser device is particularly suitable for detection by self-mixing effects. Preferably, in this case, the photodiode is used for directly detecting any overlap of the radiation emitted and backscattered in the laser cavity. Particularly preferably, the laser device can comprise a plurality of surface emitters, each emitting a laser beam.

[0029] Preferably, at least one surface emitter with a photodiode integrated therein is arranged on the glasses frame and / or on the glasses temples. In this case, the glasses frame is particularly regarded as the area of ​​the smart glasses surrounding the glasses lens, and the glasses temples are particularly regarded as holding legs connected to the glasses frame, for example extending to the user's ears. For example, several surface emitters with integrated photodiodes can be arranged distributed around the glasses lens on the glasses frame to allow a particularly precise scanning of the eye throughout its range of movement. Alternatively or additionally, one or more laser sources can be integrated, preferably molded into the glasses lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In the following, the present invention is described by way of example embodiments in conjunction with the accompanying drawings. In the accompanying drawings, components with the same function are each represented by the same reference numeral, wherein:

[0031] Figure 1 is a simplified schematic diagram of a pair of smart glasses according to a first embodiment of the present invention.

[0032] Figure 2 is used Figure 1 Simplified schematic detail view of the gaze detection process of smart glasses.

[0033] Figure 3 is used Figure 1 Another simplified schematic detail view of smart glasses implementing gaze detection.

[0034] Figure 4 is from when performing gaze acquisition Figure 1 Simplified schematic representation of the measurement data of the smart glasses.

[0035] Figure 5 is used Figure 1 Another simplified schematic detail view of the gaze acquisition execution of the smart glasses, and

[0036] Figure 6 is a simplified schematic diagram of smart glasses according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0037] Figure 1 A simplified schematic diagram of a pair of smart glasses 50 according to a first embodiment of the present invention is shown. The smart glasses 50 include glasses lenses 52, glasses frames 51 in which the glasses lenses 52 are accommodated, and glasses temples 53 for holding the smart glasses 50 on the user's head. Therefore, the smart glasses 50 are configured to be worn on the user's head.

[0038] The smart glasses 50 comprise a gaze detection device 20, by means of which the gaze direction of the user's eye 10 can be determined. To this end, the gaze detection device 20 comprises a laser device 3 and a control device 4, which is arranged to operate the laser device 3 to perform a corresponding method for detecting the gaze direction of the eye 10. For the sake of compact design, the control device 4 is arranged in the temple 53 of the smart glasses 50.

[0039] The laser device 3 includes a total of five surface emitters 3a, 3b, 3c, 3d, 3e as laser sources. Four of the five surface emitters 3a, 3b, 3c, 3d are distributedly arranged on a glasses frame 51 surrounding a glasses lens 52. The fifth surface emitter 3e is arranged on a glasses leg 53. Each surface emitter 3a, 3b, 3c, 3d, 3e is arranged to irradiate a wavelength-modulated laser beam 1 onto an eye 10. In this case, a triangular wave modulated laser is emitted as a laser beam 1 within a wavelength range. For the sake of clarity, only a single laser beam 1 emitted by the first surface emitter 3a is shown in the figure. Each laser beam 1 is directed onto the ocular surface 11 of the eye 10 with a separate laser spot 30a, 30b, 30c, 30d, 30e.

[0040] Figure 2 The laser spots 30a, 30b, 30c, 30d of the first four surface emitters 3a, 3b, 3c, 3d arranged on the eyeglass frame 51 are shown. Figure 3 , the fifth laser spot 30 e generated by the fifth surface emitter 3 e is displayed on the side of the eye 10 .

[0041] like Figure 2 and Figure 3 As shown, the laser spots 30a, 30b, 30c, 30d, 30e are preferably located in or near the area of ​​the iris 12 of the eye 10. As a result, when the eye 10 moves, the pupil 13 of the eye 10 often moves close to or passes through the laser spot 1, so that the position and movement of the pupil 13 can be determined with high accuracy to determine the gaze direction of the eye with high accuracy.

[0042] The implementation of the method for detecting the gaze direction of eye 10 is described in detail below, which is based on only a single laser beam 1 .

[0043] Firstly, a laser beam 1 is irradiated onto the eye 10. At the eye surface 11, the laser beam 1 will be at least partially backscattered. As a result, an overlap of the irradiated laser beam 1 with the portion of the backscattered radiation that propagates backwards in parallel in the direction of the surface emitter 3a occurs. Using a photodiode integrated in the surface emitter 3a, laser feedback interferometry is performed to detect the generated interference radiation, i.e. the overlap of the irradiated laser radiation 1 and the radiation backscattered in the opposite direction. Since the photodiode is directly integrated into the laser cavity of the surface emitter 3a, the detection of the generated interference radiation is performed by the so-called self-mixing effect.

[0044] exist Figure 4 Schematically shown in FIG. 2 is an exemplary spectrum 25 of the generated interference radiation which can be detected by the integrated photodiode of the surface emitter 3 a. Axis 25 a corresponds to the frequency and axis 25 b corresponds to the amplitude. Reference numeral 26 denotes the peak frequency of the detected interference radiation, which is determined, for example, by Fourier analysis. Due to the triangular modulation of the wavelength of the emitted laser beam 1, the peak frequency 26 depends on the optical path length 2. The optical path length 2 (see Figure 1 ) corresponds to the distance between the surface emitter 3a and the eye surface 11 covered by the laser beam 1. When the laser beam 1 is irradiated directly onto the eye 10, Figure 1 In the first embodiment, the optical path length 2 corresponds to the shortest distance between the surface emitter 3a and the eye surface 11. Therefore, in case the wavelength of the emitted laser beam 1 is known, the optical path length 2 can be determined for a specific eye position (i.e. for a specific gaze direction) based on laser feedback interferometry.

[0045] Figure 4 An exemplary spectrum 25 is shown, which is recorded during a constant movement of the eye surface 11 relative to the laser beam 1, i.e. during a rotation of the eye 10. During such a movement, due to the Doppler effect, a shift 27 of the peak frequency 26 towards a shifted peak frequency 26' as shown by the dashed line occurs. Therefore, the resulting Doppler shift of the emitted laser radiation and the backscattered laser radiation can be determined based on the spectrum 25. Based on this Doppler shift, the instantaneous eye velocity of the movement of the eye 10 and the direction of movement can be determined.

[0046] Preferably, in addition to detecting the frequency of the impinging and backscattered laser radiation, the reflectivity of the eye 10 can also be detected based on the amplitude and phase of the radiation backscattered by the eye 10. In this context, the reflectivity is defined as the complex reflectivity with the amplitude and phase of the radiation backscattered by the eye 10, wherein the reflectivity is different for different areas of the eye 10. In particular, the determined reflectivity changes when the laser beam 1 passes through anatomical boundaries of the eye 10, such as the iris 12 or the pupil 13. Therefore, the reflectivity of the eye 10 can be used to estimate which area of ​​the eye 10 is currently impinging on the laser beam 1. Together with the determined optical path length 2, the instantaneous absolute eye position of the eye 10 can therefore be determined.

[0047] Thus, any eye movements can be determined based on laser feedback interferometry using the eye tracking device 20, wherein any eye movement of the eye 10 can be determined and tracked. In conjunction with a determination of the absolute eye position, which is performed, for example, only at predetermined times, and additionally based on the reflectivity, the instantaneous gaze direction of the eye 10 can be determined. Due to the components required to perform the gaze direction determination, a particularly high temporal resolution of the gaze direction determination can be achieved with a low energy requirement. In addition, particularly low-cost components can be used.

[0048] Furthermore, a pair of smart glasses 50 comprises an input and / or output device 7, which is configured to provide an output to a user. The input and / or output device 7 comprises a projection unit, which is arranged to project an image onto the retina of the eye 10. The projection unit can, for example, be used to display an augmented or virtual reality (also: augmented reality AR or virtual reality). Preferably, the projection unit is coupled to the control device 4, wherein the control device 4 is arranged to operate the projection unit depending on the determined gaze direction.

[0049] By means of the control device 4, the projected image can thus be adjusted depending on the gaze direction. For particularly efficient and user-friendly operation, the image parameters of the image projected by the projection unit are adjusted depending on the position of the fovea (fovea) of the eye 10, which corresponds to the sharpest vision area. In this regard, the position of the fovea can be determined based on any previous calibration of the eye detection device 20.

[0050] Thus, the image projected by the image projection unit will be adjusted such that in the region of the fovea there is a higher image sharpness and a higher image resolution than in the circumferential region of the visual field. Preferably, the image sharpness and / or the image resolution decreases radially outwards relative to the user's visual field. In this way, a particularly efficient operation of the smart glasses 50 can be provided, since a lower display quality of the image projection unit can be achieved in regions where the visual capabilities are less pronounced for anatomical reasons. This results in a lower computational effort and a particularly low energy demand for the smart glasses 50.

[0051] In addition, eye gestures can be recognized using the eye tracking device 20. For example, various predetermined eye gestures can be assigned to different predetermined actions of the smart glasses 50. For example, an eye gesture can be defined as a predetermined sequential movement of the eye 10. For example, the eye gesture can be a vertical downward turn followed by a horizontal turn to the right. This corresponds to the user first looking down and then looking to the right.

[0052] If such an eye gesture is detected based on the eye velocity and the optical path length 2 determined using the eye tracking device 20, the image projection unit can be operated in a predetermined manner. For example, the image projection unit can be activated or deactivated to enable the smart glasses 50 to be operated as desired and thus in a particularly energy-saving manner. Alternatively or additionally, the eye gesture can be used to activate the operation of a menu option of the content displayed in augmented or virtual reality. For example, it is particularly convenient if a specific eye gesture, preferably an upward and / or downward scrolling of the eye 10, activates the scrolling of the content displayed in augmented reality or virtual reality.

[0053] exist Figure 5 A particularly simple and energy-saving way of operating the smart glasses 50 is shown in FIG. Figure 5 , an operating state of the smart glasses 50 is shown, wherein the input unit and / or the output unit 7 is deactivated and the eye tracking device 20 is in sleep mode. In sleep mode, only exactly one surface emitter 3b of the gaze detection device 20 is operable, while all other surface emitters 3a, 3c, 3d, 3e are deactivated. By a single activated surface emitter 3b, only a single laser beam 1 is directed to the eye 10 in exactly one laser port 30b, as Figure 5 shown.

[0054] In sleep mode, a simplified eye detection will be performed. Specifically, for example, only the optical path length 2 is determined. Based on the optical path length 2, it can be determined when the eye 10 moves into a position such that a single laser beam 1 can enter the eye 10 through the pupil 13. This applies to Figure 5 , when the user is looking downward, i.e. when the eye 10 performs a vertical downward rotation toward direction A. This specific eye gesture, i.e. the state when the laser beam 1 enters the eye 10, is used here to activate the projection unit and the inactive part of the eye tracking device 20. By emitting a single laser beam 1 as visible light from the surface emitter 3b, feedback about the activation can be indicated to the user.

[0055] Figure 6 A simplified schematic diagram of a pair of smart glasses 50 according to a second embodiment of the present invention is shown. The second embodiment corresponds substantially to Figure 1 The first embodiment of the invention is similar to that of the invention but differs in that the laser device 3 is arranged in an alternative manner. Figure 6In a second embodiment of the eye tracking device 20, the laser device 3 comprises four surface emitters 3a, 3b, 3c, 3d including integrated photodiodes, all of which are arranged on the temple 53 of the eyeglasses. Therefore, the laser beam 1 emitted by the surface emitters 3a, 3b, 3c, 3d will be irradiated indirectly onto the eye 10. In particular, the laser beam 1 is irradiated onto the eyeglass lens 52, taking the focal point 1' on the eyeglass lens 52 as an example. A deflection element 54 in the form of a holographic optical element is integrated in the eyeglass lens 52 to deflect the laser beam 1 towards the eye 10. In this way, an alternative arrangement of the laser device 3 can be provided, by which the optical path length 2 and the eye velocity can also be efficiently determined as a basis for operating the input unit and / or the output unit 7.

Claims

1. A method for operating a pair of smart glasses (50), the pair of smart glasses (50) comprising an input unit and / or an output unit (7) and a gaze detection device (20), wherein: The gaze detection device (20) detects any eye movement of the eye (10) by means of the method, the method comprising the following steps: irradiating at least one wavelength-modulated laser beam (1) onto the eye (10), detecting an optical path length (2) of the irradiated laser beam (1) based on laser feedback interferometry of the irradiated laser beam (1) and the portion of the laser beam (1) backscattered from the eye (10), Based on the laser feedback interferometry, the Doppler shift of the incident laser beam (1) and the backscattered portion is detected, and detecting eye velocity based on the Doppler shift, and wherein the input unit and / or the output unit (7) operates based on the optical path length (2) and / or the eye speed, and The gaze detection device (20) directs a single laser beam (1) toward the eye (10), wherein, based on the detected optical path length (2), it is detected when the single laser beam (1) enters the eye (10) through a pupil (13), and wherein, based on the detection of the single laser beam (1) entering the eye (10), the input unit and / or the output unit (7) and / or a part of the gaze detection device (20) are operated.

2. The method according to claim 1, wherein: The input unit and / or the output unit (7) is activated or deactivated based on the optical path length (2) and / or the eye speed.

3. The method according to claim 1, wherein: An eye gesture is detected based on the optical path length (2) and / or the eye velocity, and wherein the input unit and / or the output unit (7) operates based on the detected predetermined eye gesture.

4. The method according to claim 1, wherein: The input unit and / or the output unit (7) comprises an image projection unit for projecting an image onto the retina.

5. The method according to claim 4, wherein: Image parameters of the image projected by the image projection unit are adjusted based on the optical path length (2) and / or eye velocity.

6. The method according to claim 5, wherein: The image clarity and / or image resolution and / or brightness and / or color distribution of the image projected by the image projection unit is adjusted.

7. The method according to claim 1, further comprising the steps of: Detecting maximum eye velocity during eye movements, and predicting an eye movement end position based on the maximum eye velocity, Wherein, the input unit and / or the output unit (7) operates based on the end position of the eye movement.

8. The method according to claim 1, wherein: The input unit and / or the output unit (7) comprises a sound reproduction unit and / or an electronic user device.

9. The method according to claim 1, wherein: Eyelid closure of the eye (10) is detected based on the optical path length (2) and / or the eye velocity.

10. The method according to claim 1, wherein: At least a part of the gaze detection device (20) is always active.

11. The method according to claim 1, further comprising the steps of: detecting any reflectivity of the eye (10) based on the amplitude and phase of radiation backscattered from the eye, Wherein, the input unit and / or the output unit (7) is operated based on the reflectivity.

12. A pair of smart glasses, including: an input unit and / or an output unit (7) arranged to receive input from a user and / or provide output to a user; and a gaze detection device (20) for detecting any eye movement of the eye (10), The gaze detection device (20) comprises a laser device (3) adapted to irradiate at least one laser beam (1) towards the eye (10) and a control device (4) adapted to operate the laser device (3), and Wherein, the smart glasses (50) are adapted to perform the method according to any of the preceding claims.

13. A pair of smart glasses according to claim 12, wherein: The laser device (3) comprises at least one surface emitter (3a, 3b, 3c, 3d, 3e) in which a photodiode is integrated.

14. A pair of smart glasses according to claim 13, wherein: The at least one surface emitter (3a, 3b, 3c, 3d, 3e) in which the photodiode is integrated is arranged on a spectacle frame (51) particularly surrounding a spectacle lens (52), and / or on a spectacle temple (53), and / or in a spectacle lens (52).

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