Sensor unit for smart glasses, method for operating a sensor unit in smart glasses, and smart glasses

Abstract

The invention relates to a sensor unit (105) for smart glasses. The sensor unit (105) comprises at least one sensor (605a) for sensing a viewing direction of an eye, the at least one sensor (605a) being designed as a laser feedback interferometry sensor. The sensor unit (105) also comprises a deflection device (605e) having an electroactive polymer material (605g) and electrodes (605i). The deflection device (605e) is mechanically coupled to the at least one sensor (605a) and is designed to move the at least one sensor (605a), in response to an electrical voltage (U) applied to the electroactive polymer material (605g) via the electrodes (605i), in order to deflect light beams emitted by the at least one sensor (605a).

Description

[0001] R. 416101

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[0003] Description

[0004] title

[0005] Sensor unit for smart glasses, method for operating a sensor unit in smart glasses and smart glasses

[0006] State of the art

[0007] The invention relates to a sensor unit for smart glasses, a method for operating a sensor unit in smart glasses, and smart glasses according to the preamble of the independent claims. The present invention also relates to a computer program.

[0008] For example, static laser sensors, particularly laser feedback interferometry (LFI) sensors, can be used in smart glasses. The laser beam of the individual LFI sensor is designed to strike the eye to measure the surface velocity of the eye and eye movement. The so-called eyebox, i.e., the area in which the eye can be located and tracked, should be enlarged to enable a system with static LFI sensors to be used for the mass market and to accommodate various head shapes, interpupillary distances, eye shapes, eyelid shapes, etc. Such LFI sensors for eye tracking can be implemented as laser feedback interferometry sensors to capture gaze gestures, scanned laser feedback interferometry sensors for eye tracking, or LFI sensors without a scanner for eye tracking.Mechanical beam deflection in general can be achieved, for example, by mirrors, MEMS micromirrors, galvo mirrors or the like, by diffractive elements that deflect the beam, such as holographic optical elements, by rotating prisms, by electroactive polymers (EAPs) for haptic display applications, or by shape memory alloy elements. R. 416101.

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[0010] Disclosure of the invention

[0011] Against this background, the approach presented here introduces a sensor unit for smart glasses, a method for operating such a sensor unit in smart glasses, and smart glasses according to the main claims. Advantageous further developments and improvements of the device specified in the independent claim are possible through the measures listed in the dependent claims.

[0012] A sensor unit for smart glasses is presented, the sensor unit having the following features:

[0013] at least one sensor for detecting the gaze direction of an eye, wherein the at least one sensor is designed as a laser feedback interferometry sensor; and

[0014] A deflection device comprising an electroactive polymer material and electrodes, wherein the deflection device is mechanically coupled to the at least one sensor, wherein the deflection device is configured to move the at least one sensor in response to an electrical voltage applied to the electroactive polymer material via the electrodes, in order to deflect light rays emitted by the at least one sensor.

[0015] A laser feedback interferometry sensor, or LFI sensor, is a detection device in which a laser beam is emitted from the sensor onto an external reflective surface and reflected back into the sensor. Depending on the degree of reflectivity of this reflective surface, and depending on a specific distance from the sensor, the intensity or amplitude of a particular wavelength varies, resulting in a corresponding sensor signal. Specifically, by evaluating this amplitude, represented by the sensor signal, it is possible to determine the degree of reflectivity of the reflective surface onto which the light beam is currently emitted. Knowing that the retina of the eye, which is... R. 416101

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[0017] Since the pupil, illuminated by a light beam, has a different refractive index than the sclera (i.e., an outer part of the eye), it is possible, given the position or angle of the light beam, to determine whether the light beam passes through the pupil and onto the retina. By analyzing this sensor signal, the position of the pupil, and thus the eye itself, can be determined. In this way, the eye's gaze direction can be ascertained.Even when the light beam is spread out and illuminates a larger area of ​​the eye, the amplitude value of the sensor signal, which represents a degree of retinal reflection, can determine what proportion of the light beam passes through the pupil and is reflected by the retina. This allows the position of the pupil, and therefore the direction of gaze, to be determined. The sensor can be configured to detect the direction of gaze and, optionally, the trajectory of that gaze and, additionally or alternatively, the speed of eye movement—in other words, to perform eye tracking. The sensor can also include at least one optical element, which can also be referred to as optics.The sensor, at least one, can be mounted or arranged on a substrate, such as an interposer board, a ceramic holder, etc. The sensor unit can integrate a single sensor or multiple sensors. For example, several sensors or LFI sensors can be mounted on a common substrate or mounted discretely. Alternative deflection devices or mechanisms can be based on piezoelectric actuation, magnetic deflection (as in a static MEMS mirror), shape memory alloys (SMA), electrostatic microactuators, or similar technologies.

[0018] According to embodiments, in particular, the integration of a mechanical deflection device into a static laser feedback interferometry sensor unit for eyebox magnification can be provided. For example, at least one laser feedback interferometry sensor R. 416101 can be used.

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[0020] (LFI sensor) for tracking the eye. Electroactive polymers (EAPs) can also be used for the mechanical displacement and, additionally or alternatively, rotation of the LFI sensor. Such an EAP can thus be used for the mechanical displacement and, additionally or alternatively, rotation of an integrated optic. EAPs can enable static deflections with low power consumption. For example, a laser beam can be adjusted to actively enlarge the eyebox. Only small movements of a few degrees are required to significantly enlarge the eyebox. Such small movements can be caused by small voltages, which prevents overstressing of the polymers and thus extends their lifespan. This can reduce power consumption when forces need to be held statically.Thus, advantages of using static LFI sensors without scanners can still be achieved, i.e., in contrast to classic camera-based solutions, very high update rates of, for example, more than 1 kHz can be enabled with low power consumption.

[0021] According to one embodiment, the electrodes of the deflection device can be arranged in several spatially separated zones. A zone-specific electrical voltage can be applied to the electrodes in each zone. Such an embodiment offers the advantage that reliable and precise movement of the sensor, and thus deflection of the light beam, can be achieved in at least two spatial axes.

[0022] The sensor unit can also include a lens tube that incorporates an optical lens for manipulating the light rays from the at least one sensor. The at least one sensor can be integrated into the lens tube. This embodiment offers the advantage that the at least one sensor can be protected within the lens tube.

[0023] The at least one sensor can be mechanically coupled to the deflection device via the lens tube. The deflection device can thus be designed to move the at least one sensor and the lens tube, or to move them together. R. 416101

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[0025] Alternatively, the at least one sensor can be mechanically coupled to the lens tube via the deflection device. The deflection device can thus be designed to move the at least one sensor relative to the lens tube. This simplifies the mechanical integration of the sensor into the overall system, as the lens tube remains rigid or does not need to be moved. Furthermore, the EAP (Electro-Axis Process) can be reduced in size, so less energy is required to move the LFI (Low Fibre Index) sensor within the lens tube, as the mass that needs to be moved by the deflection device can be minimized.

[0026] Furthermore, the sensor unit can include an integrated circuit, in particular an application-specific integrated circuit (ASIC), which can be configured to apply the electrical voltage to the electroactive polymer material. This allows the deflection device to be advantageously controlled to ensure reliable and precise movement of the at least one sensor.

[0027] The deflection device can be arranged between the at least one sensor and the integrated circuit. The at least one sensor can be integrated directly onto the integrated circuit. This embodiment offers the advantage of a space-saving sensor unit.

[0028] Alternatively, the integrated circuit can be arranged between the at least one sensor and the deflection device. In this case, the at least one sensor can be integrated directly onto the integrated circuit. The integrated circuit can then be connected to the deflection device via flexible electrical leads. This embodiment offers the advantage that the sensor unit can be implemented in a space-saving manner, while the electrical connections can be protected from stress.

[0029] A method for operating an embodiment of a sensor unit mentioned herein in a pair of smart glasses is also presented, the method comprising the following steps: R. 416101

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[0031] Detecting the gaze direction of an eye; and

[0032] Moving the at least one sensor in response to an electrical voltage applied to the electroactive polymer material via the electrodes, which depends on the detected viewing direction, in order to deflect light rays emitted by the at least one sensor depending on the detected viewing direction.

[0033] The method can also include a step of applying an electrical voltage to the deflection device, in particular to the electrodes of the deflection device. Furthermore, the method can employ an additional camera in the system with a filter tuned to the wavelength of the LFI sensors or an IR filter to observe the positions of the sensor light beams on the eye and control the deflection device accordingly, ensuring that the beams always reach the eye. Additionally, the method can use an algorithm to select active sensors from a plurality of sensors, whereby the partial beam that detects signals from the eye can be selected based on the signals (SNR, velocity, distance, spectral distribution).

[0034] This process can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, for example in a control unit.

[0035] The approach presented here further creates a control device or control unit configured to perform, control, or implement the steps of a variant of the method presented here in appropriate devices. This embodiment of the invention in the form of a control unit also allows the problem underlying the invention to be solved quickly and efficiently.

[0036] For this purpose, the control unit may include at least one processing unit for processing signals or data, at least one storage unit for storing signals or data, and at least one interface to a sensor or a R. 416101

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[0038] The actuator must be capable of reading sensor signals from the sensor or outputting data or control signals to the actuator and / or have at least one communication interface for reading or outputting data embedded in a communication protocol. The processing unit may be, for example, a signal processor, a microcontroller, or the like, and the storage unit may be flash memory or a magnetic storage unit. The communication interface may be configured to read or output data wirelessly and / or via a wired connection. A communication interface capable of reading or outputting wired data may, for example, read or output this data electrically or optically from or into a corresponding data transmission line.

[0039] In this context, a control unit can be understood as an electrical device that processes sensor signals and outputs control and / or data signals accordingly. The device may have an interface, which can be implemented in hardware and / or software. In the case of a hardware-based interface, the interfaces can, for example, be part of a so-called system ASIC, which incorporates various functions of the device. However, it is also possible that the interfaces are separate integrated circuits or at least partially comprised of discrete components. In the case of a software-based interface, the interfaces can be software modules, which, for example, are located on a microcontroller alongside other software modules.

[0040] Also advantageous is a computer program product or computer program with program code that may be stored on a machine-readable carrier or storage medium such as semiconductor memory, hard disk memory, or optical memory and is used to carry out, implement, and / or control the steps of the method according to one of the embodiments described above, particularly if the program product or program is executed on a computer or device. R. 416101

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[0042] Furthermore, a pair of data glasses with at least one example of an embodiment of a sensor unit mentioned herein is presented.

[0043] In a pair of smart glasses, at least one sensor unit in a variant presented here can be used to enlarge the usable eyebox of the smart glasses.

[0044] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows:

[0045] Fig. 1 shows a schematic representation of an exemplary embodiment of data glasses;

[0046] Fig. 2 shows an exemplary amplitude spectrum for the operation of the data glasses in a first case, i.e., during movement without modulation;

[0047] Fig. 3 shows an exemplary amplitude spectrum for the operation of the data glasses in a second case, i.e., during movement with modulation;

[0048] Fig. 4a shows a diagram of two time profiles of the parameters l(t) and the power Pt using a triangular modulation approach, which also allows for simultaneous measurement of the distance to the target;

[0049] Fig. 4b shows a diagram of two time courses of the parameters l(t) and the power Pt using a triangular modulation approach, which also allows for simultaneous measurement of the distance to the target;

[0050] Fig. 5 shows a schematic representation of an eye during operation of a sensor unit of data glasses;

[0051] Fig. 6a shows a schematic representation of an embodiment of a sensor unit for data glasses;

[0052] Fig. 6b shows a schematic representation of an embodiment of a sensor unit for smart glasses; R. 416101

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[0054] Fig. 7 shows a schematic representation of an embodiment of a sensor unit for data glasses;

[0055] Fig. 8a shows a schematic representation of an embodiment of a sensor unit for data glasses;

[0056] Fig. 8b shows a schematic representation of an embodiment of a sensor unit for data glasses;

[0057] Fig. 9 shows a schematic representation of an embodiment of a sensor unit for smart glasses; and

[0058] Fig. 10 shows a flowchart of an exemplary embodiment of a method for operating a sensor unit in data glasses.

[0059] In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and acting similarly, without repeating these elements.

[0060] Fig. 1 shows a schematic representation of an embodiment of a pair of smart glasses 100. The smart glasses 100 comprise a sensor unit 105 with at least one laser feedback interferometry sensor (hereinafter also referred to as LFI sensor), which is configured to emit a light beam 110, here designed as a laser beam, onto a part of the eye 115 of a user of the glasses 100. The light beam 110 can strike at least partially the sclera 120, i.e., the sclera, the iris 125, or the pupil 130. If the light beam 110 strikes the pupil 130, it penetrates the interior of the eye 115 and is reflected by the retina 135. If the light ray 110 hits the sclera 120 or the iris 125, it will indeed be reflected, but due to the lower reflectivity of the sclera 120 or the iris 120, it will be reflected with significantly less intensity than if it were reflected by the retina 135.The reflected beam can then be returned to R. 416101.

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[0062] The laser feedback interferometry sensor of the sensor unit 105 is coupled in so that a sensor signal 140 can be provided from the intensity of the reflected light beam 110, the amplitude of which represents the intensity of the reflected light beam 110. From this sensor signal 140, it can then be determined, for example, in a corresponding determination unit 145, in which direction 150 the eye 115 is oriented.

[0063] This allows, for example, the exploitation of the fact that at a high intensity of the reflected light beam 110, the gaze direction 150 of the eye 115 is directed towards an area very close to, or near, the laser feedback interferometry sensor 105, and at a low intensity of the reflected light beam 110, the gaze direction 150 of the eye 115 is not directed towards the laser feedback interferometry sensor 105, so that the light beam 110 falls on the sclera 120 or the iris 125 and is thus reflected with lower intensity than if it were to fall on the retina 135. In the determination unit 145, an alignment signal 155 can then be determined, which represents the current gaze direction 150 of the eye 115 and which can be sent, for example, to a display unit 160.A display is output to output or show information in a corresponding area of ​​a spectacle lens 165 of the glasses 100, so that the output or displayed information is directly and clearly visible to a user of the glasses 100 in their field of vision.

[0064] It is also conceivable that the alignment signal 155 is output to a corresponding varifocal lens 170 to control a corresponding change in refractive power, thus enabling, for example, a very comfortable adjustment of the refractive power of the spectacle lens 165 to the user. Depending on the direction of gaze 150, the refractive power of the spectacle lens 165 can be adjusted for distance vision or night vision. It is also conceivable that, with appropriate adjustments to eye parameters, which can change with age, for example, a new adjustment of the refractive powers required for the different directions of gaze 150 can be made, so that the spectacles 100 can continue to be used as such, and only the lens power for the different directions of gaze 150 needs to be readjusted. R. 416101

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[0066] An important element for realizing the approach proposed here is the use of at least one laser feedback interferometry sensor in the sensor unit 105. This sensor is already technically mature and available and could, for example, be embedded directly on or in the spectacle lens 165. However, it is also conceivable that the laser feedback interferometry sensor is located in a lateral area of ​​the smart glasses 100, for example, next to the display unit 160, and that only a corresponding optical element for deflecting, widening, or reflecting the light beam 110 is provided on or in the spectacle lens 165. This would allow the sensor to be positioned on or in the smart glasses 100 according to the available installation space.

[0067] The sensor unit 105 will be discussed in more detail with reference to the following figures. The data glasses 100 include at least the sensor unit 105, whereby the other components of the data glasses 100 mentioned above are optional and / or can be replaced by similar or other components.

[0068] The basic operating principle of a laser feedback interferometry sensor, or LFI sensor, is already known. The approach presented here focuses on the advantageous use of this sensor component.

[0069] The following is a basic LFI procedure.

[0070] The operating principle of a laser is based on an optical resonator.

[0071] Within the resonator, electrons are excited by an external energy input. The radiation, initially generated by spontaneous emission, is guided multiple times through the interior of the optical resonator, for example, by mirrors. The resulting oscillating electromagnetic wave excites the electrons to emit in phase, producing coherent radiation. A mirror element with low transmittance, for example 1%, is located on one side to couple the resulting laser radiation out of the resonator. In the case of a Vertical Cavity Surface Emitting Laser (VCSEL), layers designed as a Distributed Bragg Reflector (DBR) are used as the optical mirror. R. 416101

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[0073] The underlying physical principle of an oculography system is based on so-called "laser self-mixing." When the coherent radiation emitted by a laser is scattered by a surface, some of this radiation returns to the laser cavity, the optical resonator. If twice the distance to the scatterer corresponds to an integer multiple of the wavelength, the backscattered radiation is in phase with the radiation in the laser cavity. It thus adds constructively to the radiation already present there, reducing the lasing threshold and thereby increasing the laser's output power. If the distance to the scatterer, and thus the optical path length, is changed, positive or negative interference occurs repeatedly within the laser cavity, depending on the distance. This causes the laser power to modulate in an oscillating pattern between a radiation maximum and a radiation minimum.Alternatively, the current driving the laser can be ramp-modulated, thereby modulating the laser's wavelength. At a fixed distance, this also changes the number of wavelengths that "fit" into the optical path, resulting in the described oscillating temporal interference pattern. If the optical radiation power is then measured by a photodiode (monitoring photodiode), the change in the amplitude of the radiation power can be used to infer the change in intensity of the backscattered laser power.

[0074] By analyzing the number of oscillations (e.g., by counting the zero crossings or maximum values, or by calculating a Fourier spectrum and analyzing the amplitude in the frequency domain), the number of oscillations (transmissions of constructive and destructive interference) can be determined, and thus, given a known laser wavelength, the distance between the laser cavity and the scatterer can be calculated. A similar effect occurs with a scatterer moving parallel to the laser beam. Here, according to the Doppler effect, the frequency of the backscattered laser light changes. At low speeds, this can be approximated as a phase shift of the backscattered laser light in the laser cavity, leading, analogously to the effect described above, to oscillating oscillations of positive and negative interference (formation of a beat frequency). This beat frequency fb is directly proportional to the R. 416101

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[0076] Velocity v of the scatterer, where the speed of light Co, the angle a between laser beam and motion vector and the exciting laser frequency fo are known: fb = 2v / co*fo cos(a).

[0077] The ViP system can be operated in two different modes. In the first case, the laser operates unmodulated, meaning the wavelength / frequency of the laser does not change over time. In the second case, the frequency of the laser is modulated over time, for example, in the form of a triangular ramp function.

[0078] Fig. 2 shows an exemplary amplitude spectrum 200 for the operation of the data glasses 100 in a first case, i.e., during movement without modulation. The amplitude on the ordinate 210 is shown as a function of the frequency plotted on the abscissa 220. During movement, a signal 230 is displayed, the center frequency of which is directly correlated with the velocity component in the direction of the beam.

[0079] Fig. 3 shows an exemplary amplitude spectrum 300 for the operation of the data glasses 100 in a second case, i.e., during movement with modulation. Without movement, a signal comparable to the signal in Fig. 2 is obtained, where the frequency represents the distance between the scatterer and the ViP sensor. If movement occurs in addition, the signal splits into two signal components 310 and 320, where the distance 330 between the signal components is correlated with the velocity. In this way, distance, velocity, and the direction vector of the velocity can be determined.

[0080] Fig. 4 shows a diagram of two time histories of the parameters l(t) (Fig. 4a) and the power Pf (Fig. 4b) using a triangular modulation approach, which also allows for simultaneous measurement of the distance to the target.

[0081] The distance-dependent beat frequency fb can be determined by an FFT.

[0082] If multiple targets are located within the area illuminated by the LFI sensor, they all scatter a portion of the scattered light back, resulting in a superposition of several frequencies that leads to a spectral distribution in the FFT. This superposition is subsequently referred to as the distance spectrum. R. 416101

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[0084] This is referred to as the velocity spectrum. Similarly, there is a velocity spectrum which contains the Doppler frequencies fd. If different targets move at different speeds, a superposition of Doppler frequencies can also be observed in the spectrum. This superposition of Doppler frequencies in the spectrum is subsequently referred to as the velocity spectrum.

[0085] Fig. 5 shows a schematic representation of an eye 115 during operation of a sensor unit of smart glasses. The sensor unit corresponds to the sensor unit from one of the figures described herein. The iris 125 and the pupil 130 of the eye 115 are shown in particular. The eye 115 is struck by infrared laser beams or light beams from at least one LFI sensor, with the points of impact of the light beams being shown in the figure.

[0086] Measurement points 110a, 110b, 110c, and 110d are displayed on eye 115. This creates the so-called eyebox 510, within which at least one LFI sensor intersects eye 115, allowing the ocular surface velocity and / or gaze direction to be measured. By controlling or actively redirecting, deflecting, or deflecting the LFI IR laser beam of the sensor unit, the measurement points 110a, 110b, 110c, and 110d on eye 115 can be shifted. For example, the initial points of impact 110b and 110d of two LFI sensors can be moved to new positions or new measurement points 110a and 110c on eye 115 by activating the deflection device or the EAP (Eye Action Point) and the associated redirection. Thus, the LFI sensors follow the position or gaze direction of eye 115.

[0087] Fig. 6a shows a schematic representation of an embodiment of a sensor unit 105 for smart glasses. The sensor unit 105 is intended for use in smart glasses that are similar to or correspond to the smart glasses from Fig. 1. Thus, the sensor unit 105 shown here is similar to or corresponds to the sensor unit from Fig. 1. In the representation of Fig. 6a, the sensor unit 105 is shown in a schematic sectional view.

[0088] The sensor unit 105 comprises at least one sensor 605a for detecting the gaze direction of an eye. The at least one sensor 605a is designed as a laser feedback interferometry sensor. According to R. 416101

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[0090] In an exemplary embodiment, the at least one sensor 605a also includes its own optics 605c.

[0091] The sensor unit 105 further comprises a deflection device 605e with an electroactive polymer material 605g and electrodes 605i. The deflection device 605e is mechanically coupled to the at least one sensor 605a. The deflection device 605e is configured to move the at least one sensor 605a in response to an electrical voltage applied to the electroactive polymer material 605g via the electrodes 605i, in order to deflect light rays 110 emitted by the at least one sensor 605a.

[0092] According to one embodiment, the sensor unit 105 also includes a lens tube 605k, which has an optical lens 605m for manipulating the light beams 110 from the at least one sensor 605a. The at least one sensor 605a is integrated into the lens tube 605k. The lens tube 605k thus serves as a housing for the at least one sensor 605a. According to one embodiment, and as shown in Fig. 6a and Fig. 6b, the at least one sensor 605a is mechanically coupled to the deflection device 605e via the lens tube 605k. The lens tube 605k, in which the at least one sensor 605a is arranged, is attached to the deflection device 605e.

[0093] In Fig. 6a, the sensor unit 105 is shown in a first state in which an electrical voltage U of 0 volts is applied to the deflection device 605e or, more precisely, via the electrodes 605i to the electroactive polymer material 605g. Thus, the deflection device 605e is unactuated or in a rest position, with the at least one sensor 605a being aligned in a first direction.

[0094] Fig. 6b shows a schematic representation of an embodiment of a sensor unit 105 for smart glasses. The sensor unit 105 corresponds to the sensor unit from Fig. 6a, except that in Fig. 6b the sensor unit 105 is shown in a second state in which an electrical voltage U of more than 0 volts is applied to the deflection device 605e or, more precisely, via the electrodes 605i to the electroactive polymer material 605g. Thus, the R. 416101

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[0096] The deflection device 605e is actuated or in a deflection position, wherein the electroactive polymer material 605g is deformed and the at least one sensor 605a is oriented in a second direction different from the first direction.

[0097] In other words, in Figs. 6a and 6b, the at least one sensor 605a or LFI sensor with optics 605c is mounted, for example, on an interposer board, a ceramic holder, etc., and integrated into a lens tube 605k or lens barrel. This lens tube 605k holds the optical lens 605m for beam manipulation. Below the lens tube 605k, the deflection device 605e or the EAP element with its electrodes 605i and the polymer 605g is mounted, along with a power supply to control the system.

[0098] Fig. 7 shows a schematic representation of an embodiment of a sensor unit 105 for smart glasses. The sensor unit 105, shown in a schematic top view in Fig. 7, corresponds to or resembles the sensor unit from one of the other figures described herein. According to the embodiment shown in Fig. 7, the electrodes 605i of the deflection device are arranged in several spatially separated zones 705i-1, 705i-2, 705i-3, 705i-4. A zone-specific electrical voltage can be applied to the electrodes 605i in each zone 705i-1, 705i-2, 705i-3, 705i-4.

[0099] In other words, the electrodes 605i are divided into at least one zone, preferably two zones, or particularly preferably at least four spatially separated zones 705i-1, 705i-2, 705i-3, 705i-4, so that the polymer or polymer material 605g can be deflected or stretched and compressed. Fig. 7 shows a setup with four electrodes 605i in zones 705i-1, 705i-2, 705i-3, 705i-4 and the polymer 605g between them. The lens barrel or objective tube 605k with the sensor is mounted on the EAP element, and the IR beam is emitted from the lens 605m. By controlling the four electrodes 605i, the module can be tilted in two spatial axes, thus deflecting the light beam. R. 416101

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[0101] Fig. 8a shows a schematic representation of an embodiment of a sensor unit 105 for smart glasses. The sensor unit 105, shown schematically in Fig. 8a, corresponds to the sensor unit from Fig. 6a or Fig. 6b, except that while the sensor unit 105 also includes a lens tube 605k with an optical lens 605m for manipulating the light beams 110 from the at least one sensor 605a, and the at least one sensor 605a is integrated into the lens tube 605k, the at least one sensor 605a is mechanically coupled to the lens tube 605k via the deflection device 605e. Thus, both the at least one sensor 605a and the deflection device 605e are arranged in the lens tube 605k.

[0102] In Fig. 8a, the sensor unit 105 is shown in a first state as in Fig. 6a, in which an electrical voltage U of 0 volts is applied to the deflection device 605e or, more precisely, via the electrodes 605i to the electroactive polymer material 605g. Thus, the deflection device 605e is unactuated or in a rest position, with the at least one sensor 605a being aligned in a first direction.

[0103] Fig. 8b shows a schematic representation of an embodiment of a sensor unit 105 for smart glasses. The sensor unit 105 corresponds to the sensor unit from Fig. 8a, except that in Fig. 8b the sensor unit 105 is shown as in Fig.

[0104] Figure 6b shows a second state in which an electrical voltage U of more than 0 volts is applied to the deflection device 605e or, more precisely, via the electrodes 605i to the electroactive polymer material 605g. Thus, the deflection device 605e is actuated or in a deflected position, whereby the electroactive polymer material 605g is deformed and the at least one sensor 605a is oriented in a second direction different from the first direction.

[0105] In other words, in Figs. 8a and 8b, the deflection device 605e is integrated directly into the lens tube 605k to minimize the mass that needs to be moved, rotated, or pivoted by the deflection device 605e. This simplifies the mechanical integration of the sensor unit 105 into the overall smart glasses system, since the outer barrel or lens tube 605kR. 416101

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[0107] Furthermore, the deflection device 605e can be significantly reduced in size, so that significantly less energy is required to tilt the LFI sensor in the lens tube 605k by a few degrees, for example 0 degrees to 5 degrees.

[0108] Fig. 9 shows a schematic representation of an embodiment of a sensor unit 105 for smart glasses. The sensor unit 105 and the representation in Fig. 9 correspond to the sensor unit and the representation in Fig. 8b, except that two sensors 605a and 905a are arranged on the deflection device 605e. In addition to sensor 605a with its optic 605c, another sensor 905a with further optic 905c is arranged on the deflection device 605e.

[0109] In other words, in addition to a single 605a sensor, several 605a and 905a sensors can also be integrated within an LFI sensor element or within the sensor unit 105. The 605a and 905a sensors, or LFI sensors, can be mounted on a common substrate or be mounted discretely and individually.

[0110] With reference to the figures described above, further similar embodiments of the sensor unit 105 are briefly explained below.

[0111] According to one embodiment, the sensor unit 105 further comprises an integrated circuit, in particular an application-specific integrated circuit (ASIC). The integrated circuit is configured to apply the electrical voltage to the electroactive polymer material 605g via the electrodes 605i. The integrated circuit can be configured to generate, adjust, and apply the electrical voltages. In one variant, the deflection device 605e is arranged between the at least one sensor 605a, 905a and the integrated circuit, and the at least one sensor 605a, 905a is integrated directly onto the integrated circuit, in particular onto an ASIC top surface. In another variant, the integrated circuit is arranged between the at least one sensor 605a, 905a and the deflection device 605e. The at least one sensor is... R. 416101

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[0113] The 605a and 905a are directly integrated onto the integrated circuit, and the integrated circuit is connected to the deflection device 605e via flexible electrical leads. In other words, the deflection device 605e, along with the EAP or polymer material 605g, is positioned beneath the integrated circuit or ASIC, and at least one sensor 605a, 905a, or LFI sensor is directly bonded to the integrated circuit. Flexible electrical leads between the ASIC and the EAP are provided to protect the bond wires of the LFI sensor from mechanical stress caused by the tilting of the deflection device 605e.

[0114] Alternative deflection mechanisms for the deflection device 605e may, according to other embodiments, also include piezoelectric actuation, magnetic deflection, shape memory alloys (SMA), electrostatic microactuators or the like.

[0115] Fig. 10 shows a flowchart of an embodiment of method 1000 for operating a sensor unit in smart glasses. Method 1000 can be implemented in conjunction with the sensor unit from one of the figures described above or a similar sensor unit in smart glasses. Thus, method 1000 can be implemented to operate the sensor unit from one of the figures described above or a similar sensor unit in smart glasses.

[0116] The method 1000 for operation comprises a step 1002 of detecting a gaze direction of an eye and a step 1004 of moving the at least one sensor in response to an electrical voltage applied to the electroactive polymer material via the electrodes, which depends on the detected gaze direction, in order to deflect light rays emitted by the at least one sensor depending on the detected gaze direction.

[0117] According to one embodiment, in method 1000 for operation, the active sensors are also selected by an algorithm, whereby the partial beam that detects signals from the eye can be selected based on signals (SNR, velocity, distance, spectral distribution). According to one embodiment, in method 1000 for operation, R. 416101

[0118] - 20 -

[0119] A camera or additional camera in the system with a filter or IR filter tuned to the wavelength of the LFI sensors can be used to observe the positions of the sensors on the eye and to control the EAP accordingly, so that the rays always hit the eye.

[0120] If an embodiment includes an “and / or” connection between a first feature and a second feature, this is to be read as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature.

Claims

R. 416101 - 21 - Claims 1. Sensor unit (105) for a data glasses (100), wherein the sensor unit (105) has the following features: at least one sensor (605a; 905a) for detecting a gaze direction (150) of an eye (115), wherein the at least one sensor (605a; 905a) is designed as a laser feedback interferometry sensor; and a deflection device (605e) comprising an electroactive polymer material (605g) and electrodes (605i), wherein the deflection device (605e) is mechanically coupled to the at least one sensor (605a; 905a), wherein the deflection device (605e) is configured to move the at least one sensor (605a; 905a) in response to an electrical voltage (U) applied to the electroactive polymer material (605g) via the electrodes (605i) in order to deflect light rays (110) emitted by the at least one sensor (605a; 905a).

2. Sensor unit (105) according to claim 1, wherein the electrodes (605i) of the deflection device (605e) are arranged in several spatially separated zones (705i-1, 705i-2, 705i-3, 705i-4), wherein a zone-specific electrical voltage (U) can be applied to the electrodes (605i) in each zone (705i-1, 705i-2, 705i-3, 705i-4).

3. Sensor unit (105) according to one of the preceding claims, comprising a lens tube (605k) having an optical lens (605m) for manipulating the light rays (110) from the at least one sensor (605a; 905a), wherein the at least one sensor (605a; 905a) is integrated into the lens tube (605k). R. 416101 - 22 - 4. Sensor unit (105) according to claim 3, wherein the at least one sensor (605a; 905a) is mechanically coupled to the deflection device (605e) via the lens tube (605k).

5. Sensor unit (105) according to claim 3, wherein the at least one sensor (605a; 905a) is mechanically coupled to the lens tube (605k) via the deflection device (605e).

6. Sensor unit (105) according to one of the preceding claims, comprising an integrated circuit, in particular an application-specific integrated circuit, configured to apply the electrical voltage (U) to the electroactive polymer material (605g).

7. Sensor unit (105) according to claim 6, wherein the deflection device (605e) is arranged between the at least one sensor (605a; 905a) and the integrated circuit, wherein the at least one sensor (605a; 905a) is directly integrated onto the integrated circuit.

8. Sensor unit (105) according to claim 6, wherein the integrated circuit is arranged between the at least one sensor (605a; 905a) and the deflection device (605e), wherein the at least one sensor (605a; 905a) is directly integrated onto the integrated circuit, wherein the integrated circuit is connected to the deflection device (605e) via flexible electrical leads.

9. Method (1000) for operating a sensor unit (105) according to one of the preceding claims in a pair of data glasses (100), wherein the method (1000) comprises the following steps: Detecting (1002) a gaze direction (150) of an eye (115); and Moving (1004) the at least one sensor (605a; 905a) in response to a direction of gaze (150) applied via the electrodes (605i) to the electroactive polymer material (605g) from the detected direction of gaze (150). 416101 - 23 - dependent electrical voltage (U) in order to deflect light rays (110) emitted by the at least one sensor (605a; 905a) depending on the detected viewing direction (150).

10. Data glasses (100) with at least one sensor unit (105) according to one of claims 1 to 8.

Images