Contact lens and procedure using a contact lens

Abstract

A contact lens (12) is proposed, comprising at least one integrated blink sensor (10) at least for detecting a safety- and / or health-relevant blink anomaly of an eyelid of a wearer of the contact lens (12), and comprising at least one integrated output unit (14) which is configured to trigger and / or output a warning signal, wherein the integrated blink sensor (10) is designed as an acceleration sensor.

Description

State of the art

[0001] So-called "smart contact lenses" with integrated acceleration sensors specifically configured to detect relative eye positions, for example, to distinguish between a near focus and a far focus by distinguishing between slight squinting and parallel eye alignment, have already been proposed in documents US 9,671,619 B2, US 2017 / 0023793 A1, or US 10,444,541 B2. A special device with integrated acceleration sensors for detecting the head positions of the contact lens wearer is proposed in documents US 2017 / 0031159 A1 and US 2017 / 0354326 A1. The same two documents also propose the provision of additional integrated photodiodes for detecting blinking.The documents US 4,349,724 A (electrodes for detecting muscle movements) and EP 3 338 623 A1 as well as US 2015 / 0257699 A1 (magnetic sensors or acceleration sensors on the eyelid) describe other known and relatively complex alternatives to blink detection. Disclosure of the invention

[0002] A contact lens is proposed with at least one integrated blink sensor at least for detecting a safety- and / or health-relevant blink anomaly of an eyelid of a wearer of the contact lens, and with at least one integrated output unit which is configured to trigger and / or output a warning signal, wherein the integrated blink sensor is designed as an acceleration sensor.

[0003] This advantageously provides a user-friendly (no need for external sensors attached to the body, such as electrodes or magnets, etc.), cost-effective, and / or technically simple eye blink monitoring function. Advantageously, acceleration sensors are particularly compact to manufacture, particularly compared to photodiodes. Advantageously, as surface-mounted devices, acceleration sensors are particularly easy to electrically contact, particularly compared to photodiodes. Furthermore, safety can be increased, particularly through the warning signal, for example, by reliably detecting health-relevant (e.g., caused by dry eyes or emergencies such as strokes) and / or safety-relevant (e.g., caused by fatigue in traffic) eye blink abnormalities.

[0004] Contact lenses, less commonly called adhesive lenses or adhesive shells, are usually transparent, flat, and disc-shaped objects designed to float on the fine tear film of the eye. Contact lenses are often used to correct vision problems. However, there are also contact lenses that do not have optical corrective properties. These can serve cosmetic or other purposes, such as correcting the shape of the cornea (night lenses) or protecting the eye in the event of injury (bandage lenses). The contact lens can be designed as a soft contact lens or a hard contact lens. The blink sensor is designed to detect changes in condition caused by a blink of the eye wearing the contact lens.In particular, the blink sensor is designed to detect characteristic movements of at least a portion of the contact lens generated by a blink of the eye wearing the contact lens. For example, the contact lens can be slightly displaced on a surface of the eye by the blink. For example, the blink can generate a measurable shock on the contact lens. For example, the contact lens can follow a movement generated by the blink into and / or out of the eye socket of the eye.

[0005] A safety-relevant anomaly could, for example, be an eyelid blinking abnormality caused by fatigue, e.g. of a driver or a worker, etc. The publications by Morris and Miller, "Electrooculographic and performance indices of fatigue during simulated flight", Biol Psychol 1996, 42, pp. 343-360, by Caffier et al., "Experimental evaluation of eye-blink parameters as a drowsiness measure", Eur J Appl Physiol 2003, 89, pp. 319-325 or by Wilkinson et al., "The Accuracy of Eyelid Movement Parameters for Drowsiness Detection", J. Clinical Sleep Medicine 2013, Vol. 09, Issue 12, pp. 1315-1324 describe examples of eyelid blinking abnormalities that allow conclusions to be drawn about increased fatigue. Appropriate early warning messages can prevent accidents, e.g. B. traffic accidents or accidents at work, can be advantageously avoided.In addition, a fatigue parameter can advantageously be recorded, allowing, for example, subsequent evidence to determine whether a driver or worker who caused an accident was overtired. The wearer can wear a contact lens according to the invention in only one eye, but it is also conceivable for the wearer to wear contact lenses according to the invention in both eyes. These two contact lenses could then communicate with each other, for example, to perform a mutual plausibility check of the detected events, e.g., before issuing a warning message.

[0006] The integrated eyelid sensor is integrated into the contact lens, in particular into a base material of the contact lens. Preferably, the integrated eyelid sensor is embedded in the base material of the contact lens. Preferably, the eyelid sensor is completely surrounded by the base material of the contact lens. The base material is preferably a transparent plastic, which in particular comprises a region with an optical function for correcting vision defects. Alternatively, the eyelid sensor can also be applied only to one surface of the contact lens, preferably to an outer surface of the contact lens facing away from an eye surface. In particular, the eyelid sensor is arranged in a region of the contact lens which is different from the region having the optical function for correcting vision defects.Preferably, the integrated blink sensor is arranged in an edge region of the contact lens, which is designed as a (curved) disc / cup. In particular, the contact lens has a material thickness that decreases radially outward. For this reason, a particularly low overall height of the blink sensor and all other integrated electronic components of the contact lens is particularly important to maintain sufficient wearing comfort. The integrated blink sensor can have its own processing unit, such as a microcontroller, or can communicate with another integrated (e.g., a microcontroller of the output unit) or external microcontroller.

[0007] The blink sensor is designed, in particular, as an acceleration sensor, which is configured for the (continuous) measurement of accelerations of at least one measuring element of the acceleration sensor and / or of the entire acceleration sensor. In particular, the acceleration sensor detects accelerations experienced by the contact lens. The acceleration sensor can be uniaxial, biaxial, or triaxial, i.e., it can be sensitive in one, two, or three spatial directions. When using multi-axis sensors, signals measured in different axes can be quadratically added to advantageously generate a particularly low-noise measurement signal. The measurement signals of the acceleration sensor can be processed either in the acceleration sensor's own processing unit, in another processing unit of the contact lens, or in an external processing unit.

[0008] The integrated output unit can be arranged and / or formed separately from the acceleration sensor. Alternatively, the output unit can also be formed with the acceleration sensor / integrated into the acceleration sensor. The integrated output unit is formed integrated into the contact lens, in particular into a base material of the contact lens. Preferably, the integrated output unit is embedded in the base material of the contact lens. Preferably, the output unit is completely surrounded by the base material of the contact lens. Alternatively, the output unit can also be applied only to one surface of the contact lens, preferably on the outer surface of the contact lens facing away from an eye surface. In particular, the output unit is arranged in a region of the contact lens which is different from the region having the optical function for correcting vision defects.Preferably, the integrated blink sensor is arranged in the edge region of the contact lens. It is also conceivable for the contact lens to have additional electronic components integrated into the contact lens, such as an integrated battery, an integrated communications unit, and / or a separate integrated processing unit, e.g., with a separate microcontroller. The acceleration sensor can be configured separately from one or more of these additional electronic components. Alternatively, the acceleration sensor can be integrated with one or more of these additional electronic components.

[0009] The warning signal can be configured to indicate a danger associated with the detected blinking anomaly. The warning signal can be configured to indicate an eye condition associated with the detected blinking anomaly, e.g., dry eyes, etc. The warning signal can be configured to indicate a health condition associated with the detected blinking anomaly and / or a health hazard associated with the detected blinking anomaly. The warning signal can be a visual warning signal (flashing signal, color signal, etc.), a tactile warning signal (vibration, pressure, heat, etc.), and / or an acoustic warning signal. The warning signal can also be configured as a warning message in text and / or image form, for example, as a sent text message (email, SMS, etc.) or as a sent image message.The warning signal can additionally be issued by at least one further output unit, which can also be part of the contact lens or which can alternatively be assigned to an external device linked to the contact lens, such as a smartphone, a smartwatch, a VR / AR headset, a (wireless) headset, a smart ring, a smart tag or another external computer system.

[0010] It is further proposed that the blink anomaly detectable by the blink sensor be configured as an increased or decreased blink frequency compared to a normal state, for example approximately 10 blinks per minute, and / or as a blink sequence that represents an indicator of the presence of an abnormality, such as fatigue. This advantageously allows for simple and / or reliable anomaly detection. It is conceivable that the normal state is fixed. Alternatively, the normal state can also be calibrated and / or calibratable for each individual wearer. For example, the contact lens can first measure an average blink frequency for each individual wearer and use this as the basis for subsequent anomaly detection. For example, a multiple blink, i.e. a blink sequence of at least two, if necessaryEven multiple blinks in quick succession can be an indication of onset of fatigue or drowsiness. An increased blink rate can be a possible sign of extreme tension, nervousness, or a general state of stress. A decreased blink rate can be a sign of dry eyes and / or eye irritation, which can occur as a result of prolonged, concentrated reading or prolonged, concentrated screen work.

[0011] If the blink anomaly detectable by the eyelid blink sensor is a deviation from an average blink duration, simple and / or reliable anomaly detection can advantageously be carried out. An increase in the average blink duration, in particular a slowed blink, can be an indication of the onset of fatigue or drowsiness. The slowed blink leads in particular to smaller acceleration amplitudes in the measurement signal of the acceleration sensor, which, however, extend over a longer period of time than the average. For example, the deviation can be an increase in the blink duration of at least 25%, preferably by at least 50% and more preferably by at least 100%. Alternatively, blink durations that are shortened compared to the average can also be detected as an blink anomaly. It is conceivable that the average blink duration is fixed.Alternatively, the average blink duration could also be calibrated or calibrated individually for each wearer.

[0012] Furthermore, it is proposed that the integrated output unit comprise a wireless communication device, which is configured in particular for communication with an external warning system, such as a smartphone, data glasses, a headphone system, or a smartwatch. This advantageously enables an effective warning. The communication device is preferably integrated into the contact lens together with the integrated output unit. Alternatively, the communication device can be arranged and / or configured separately from the acceleration sensor and / or the output unit. Signals, in particular measurement signals, between the integrated acceleration sensor and the communication device can be transmitted via a bidirectional data protocol (e.g., I 2 C, I 3C, SPI). Signal processing of the raw data, in particular raw measurement data, of the acceleration sensor can take place in the computing unit of the acceleration sensor itself and / or in a computing unit of the communication device and / or the output unit. Several of the integrated components of the contact lens can each comprise a computing unit designed as a microcontroller, e.g., for signal processing and / or signal transmission. The communication device can be provided via a radio interface, such as Bluetooth, for communication with external devices such as smartphones, wearables and / or IoT (Internet of Things) devices. The external devices can then be configured to output the warning signals via their screens, vibrators and / or loudspeakers, etc.With a headphone system, the warning is typically acoustic, whereas with data glasses the warning is more likely to be visual or both visual and acoustic. The communication device could in principle also be part of the integrated acceleration sensor. The terms “configured” and / or “intended” should be understood to mean, in particular, specially programmed, designed and / or equipped. The fact that an object is configured and / or intended for a specific function should be understood to mean, in particular, that the object fulfills and / or executes this specific function in at least one application and / or operating state. A “computing unit” should be understood to mean, in particular, a unit with an information input, an information processing unit and an information output.The computing unit advantageously comprises at least one processor, a memory, input and output means, further electrical components, an operating program, control routines, and / or calculation routines. The components of the computing unit are preferably arranged on a common circuit board and / or advantageously arranged in a common housing.

[0013] It is further proposed that the integrated output unit comprises a visual warning element, such as a micro-LED or an integrated display, and / or a tactile warning element, such as a vibrator or a temperature control element, e.g. a heater and / or cooler. This advantageously allows for effective warning. In particular, the visual warning element and / or the tactile warning element can be integrated into the contact lens itself. The visual warning element can be formed, for example, by a light source, in particular a micro-LED. The visual warning element can be configured to generate a light signal intended to alert the wearer to deviations in the blink frequency, blink amplitude and / or blink duration.It is conceivable that a type of blinking anomaly is already classified by the computing unit of the acceleration sensor, the computing unit of the output unit, or the computing unit of the communication device. Accordingly, the warning signal could take different forms depending on the type of blinking anomaly occurring, e.g., rapid blinking to avoid danger when onset of drowsiness is detected, or simply a slow flashing when the blinking frequency is too low, since there is no acute danger in this case. If the integrated output unit is designed as a vibrator, different vibration intensities, different vibration frequencies, or different vibration patterns can be output depending on the type of blinking anomaly detected.If the integrated output unit is designed as a tempering element, in particular as the heater and / or as the cooler, a temperature can be selected differently to output the type of blinking anomaly.

[0014] It is additionally proposed that the contact lens have a further integrated eyelid blink sensor which is based on a measuring principle that is different from the measuring principle of the eyelid blink sensor. This advantageously makes it possible to achieve a particularly high level of reliability of the warning signals. False alarms can advantageously be avoided. In particular, the further integrated eyelid blink sensor is designed differently from an acceleration sensor. The further integrated eyelid blink sensor can be integrated into the contact lens together with the integrated eyelid blink sensor or separately and distinct from the integrated eyelid blink sensor. The further integrated eyelid blink sensor can be a pressure sensor, a strain sensor or a force sensor. More than one further integrated eyelid blink sensor can also be integrated into the contact lens.When the eyelid covers the eyeball and the contact lens placed on it, a slight mechanical force, and thus pressure and mechanical tension, is exerted on the contact lens. This pressure or force, however, is measurable by the proposed additional blink sensor. While an acceleration sensor reacts to eyelid movements, i.e., changes in eyelid position, a pressure, strain, and / or force sensor provides an indication of the states "eyelid open" versus "eyelid closed." A combination of the various signal signatures of the measurement signals from the various blink sensors can be used to verify the plausibility of blink detection. This can advantageously reduce the rate of false-positive blink anomalies.

[0015] If the further integrated blink sensor is designed as a pressure sensor, as a rotation rate sensor, as a strain sensor or as a combination of at least two of these three sensor types, the rate of positively detected blink anomalies can be advantageously reduced.

[0016] Furthermore, it is proposed that the contact lens have an integrated computing unit configured to perform a plausibility check of blink measurement results and / or eyelid position measurement results based on a comparison of measurement signals from the integrated blink sensor and the further integrated blink sensor. This can advantageously reduce the rate of positively detected blink anomalies. The integrated computing unit can be designed separately from the other electronic components of the contact lens or integrated with at least one other electronic component of the contact lens.

[0017] If the integrated computing unit is configured to only issue a warning signal via the integrated output unit if there is a positive result from the plausibility check of the underlying measurement signals, the rate of false notifications can be advantageously reduced.

[0018] It is also proposed that the integrated blink sensor, and in particular the further integrated blink sensor, have an overall height of less than 400 µm, preferably less than 300 µm, and more preferably less than 200 µm. This advantageously makes it possible to achieve a particularly high level of wearing comfort for the contact lens. Advantageously, integration of the blink sensor into contact lenses of commercially available dimensions, i.e., sizes and thicknesses, can be enabled. In particular, wafers and / or wafer stacks forming the integrated blink sensor are thinned back during production by grinding or by a CMP (chemo-mechanical polishing) process. The overall height corresponds in particular to a maximum overall height of the integrated blink sensor.

[0019] It is also proposed that the integrated blink sensor, and in particular the further integrated blink sensor, have a footprint of 2 mm 2or less. This allows for advantageous integration into the contact lens. Advantageously, integration can be achieved that neither impairs vision through the contact lens nor requires a significant magnification of the contact lens compared to commercially available contact lenses.

[0020] Furthermore, it is proposed that the integrated blink sensor, and in particular the further integrated blink sensor, be designed as a vertically integrated MEMS (micro-electro-mechanical system)-ASIC (application-specific integrated circuit) component and / or by a chip scale package (CSP). This advantageously makes it possible to achieve a particularly high level of wearing comfort for the contact lens. Advantageously, integration of the blink sensor into contact lenses of commercially available dimensions, i.e., sizes and thicknesses, can be enabled. Implementing the contact lens configuration according to the invention can place extreme demands on the miniaturization of the components to be integrated. In commercially available MEMS-ASIC acceleration sensors, the MEMS and ASIC chips are repackaged in a molded housing.For several years, the current industry standard for three-axis acceleration sensors for consumer electronics applications has been an LGA2x2 molded package with heights between 0.6 mm and 1.0 mm. Such standard sensors are too large, especially too thick, for integration into contact lenses. In particular, the design of the integrated blink sensor dispenses with the outer packaging of the MEMS and ASIC chips. The integrated acceleration sensor is preferably formed by a wafer stack consisting of a MEMS wafer, which is preferably manufactured using typical surface micromechanical manufacturing processes, and an ASIC wafer, which is preferably also initially manufactured using standard semiconductor manufacturing processes. The ASIC wafer is preferably a CMOS (complementary metal oxide semiconductor) wafer.The MEMS wafer preferably contains one or more functional layers, preferably made of silicon, from which conductor tracks, masses, springs, mechanical suspensions, and capacitive detection electrodes can be formed. The ASIC wafer preferably contains transistor circuits and wiring. Particularly for vertical integration, the MEMS wafer and ASIC wafer are mechanically and electrically connected to one another via a bonding layer using a metallic bonding process. The bonding layer can be produced using a eutectic bonding process, e.g., with aluminum on one wafer and germanium on the other wafer. A peripheral frame can be arranged in the bonding layer, enclosing a cavity formed by the mutually facing sides of the MEMS wafer and the ASIC wafer. Electrical contacts between the MEMS and ASIC wafers can also be established via the metallic bonding layer.An additional fixed evaluation electrode can optionally be arranged in the topmost metallization layer of the ASIC to detect movements perpendicular to the chip plane. In particular, the integrated acceleration sensor can have a single movable sensor mass, which can be deflected in multiple directions (xy, xz, or xyz) using suitable spring geometries. This configuration is particularly useful for this application, as Brownian noise is reduced due to a particularly large common sensor mass.

[0021] Furthermore, a method using a contact lens is proposed, wherein a blink sensor configured as an acceleration sensor and integrated into the contact lens detects a safety- and / or health-relevant blinking anomaly of the eyelid of a contact lens wearer, and wherein a warning signal is triggered and / or output by an output unit integrated into the contact lens. This advantageously provides a user-friendly (no need for external sensors attached to the body, such as electrodes or magnets, etc.), cost-effective, and / or technically simple blink monitoring function.

[0022] The contact lens according to the invention and the method according to the invention are not intended to be limited to the application and embodiment described above. In particular, the contact lens according to the invention and the method according to the invention may have a number of individual elements, components, units, and method steps that differs from the number stated herein to fulfill a function described herein. Furthermore, in the value ranges specified in this disclosure, values ​​within the stated limits are also to be considered disclosed and can be used arbitrarily. drawing

[0023] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0024] They show: Fig. 1 a schematic front view of a contact lens with an integrated blink sensor, Fig. 2 a schematic sectional view of an exemplary embodiment of the integrated blink sensor designed as an acceleration sensor, Fig. 3 simplifies an anomaly-free measurement signal of the blink sensor plotted over time with a normal signal shape, Fig. 4 the measurement signal of the eyelid sensor with a first exemplary signal form different from the normal Fig. 3 different signal shape, Fig. 5 the measurement signal of the eyelid sensor with a second exemplary signal form of the normal Fig. 3 different signal shape, Fig. 6 the measurement signal of the eyelid sensor with a third exemplary signal form of the normal Fig. 3 different signal shape, Fig. 7 the measurement signal of the eyelid sensor with a fourth exemplary signal form of the normal Fig. 3 different signal shape, Fig. 8 which is already in the Fig. 3 shows the ideal measurement signal of the integrated blink sensor occurring during regular blinking and another measurement signal of another integrated blink sensor, Fig. 9 the measurement signal of the integrated blink sensor and the further measurement signal of the further integrated blink sensor when the eye is closed for a longer period of time and Fig. 10 a schematic flow diagram of a process with the contact lens. Description of the embodiment

[0025] The Fig. 1 shows a schematic front view of a contact lens 12. The contact lens 12 forms an intelligent contact lens / a smart contact lens. The contact lens 12 has an integrated blink sensor 10. The integrated blink sensor 10 is designed as an acceleration sensor. The contact lens 12 has a further integrated blink sensor 24. The further integrated blink sensor 24 is based on a measuring principle that is different from a measuring principle of the blink sensor 10. The further integrated blink sensor 24 is designed as a pressure sensor. Alternatively, the further integrated blink sensor 24 could be designed as a yaw rate sensor, as a strain sensor, or as a combination of at least two of these three sensor types. Furthermore, the contact lens 12 could alternatively also have only the integrated blink sensor 10 or only several similar integrated blink sensors 10.

[0026] The integrated blink sensor 10 and / or the further integrated blink sensor 24 is configured to detect a safety- and / or health-relevant blink anomaly of an eyelid of a wearer of the contact lens 12. The blink anomaly detectable by the integrated blink sensor 10 and / or the further integrated blink sensor 24 can be configured as a deviation from an average blink duration.

[0027] The blinking anomaly detectable by the integrated blink sensor 10 and / or the further integrated blink sensor 24 can be configured as an increased or decreased blinking frequency compared to a normal state, for example, approximately 10 blinks per minute. The blinking anomaly detectable by the integrated blink sensor 10 and / or the further integrated blink sensor 24 can be configured as a blinking sequence, for example, rapid multiple blinking, that represents an indicator of the presence of an anomaly, such as fatigue.

[0028] The contact lens 12 has an integrated computing unit 26. The computing unit 26 is, for example, designed together with the integrated blink sensor 10. Alternatively, the integrated computing unit 26 could also be designed separately from other electronic components of the contact lens 12 and only communicate with one or more of them. Alternatively, the integrated computing unit 26 could also be integrated into one of the other electronic components of the contact lens 12. The integrated computing unit 26 is configured to, based on a comparison of measurement signals 56, 62 (cf. Fig. 3 to 9) of the integrated blink sensor 10 and the further integrated blink sensor 24 to perform a plausibility check of blink measurement results and / or eyelid position measurement results. The integrated computing unit 26 is configured to initiate or permit the output of a warning signal via the integrated output unit 14 only if a positive result of the plausibility check of the underlying measurement signals 56, 62 is present.

[0029] The contact lens 12 has an integrated output unit 14. The integrated output unit 14 is configured to trigger and / or output a warning signal. The integrated output unit 14 comprises an optical warning element 20. The optical warning element 20 is integrated into the contact lens 12. The optical warning element 20 is designed as a micro-LED. Alternatively, the optical warning element 20 could also be designed as an optical display that is significantly more complex than the micro-LED and can transmit information to the wearer of the contact lens 12. The integrated output unit 14 comprises a tactile warning element 22. The tactile warning element 22 is designed as a vibrator. Alternatively or additionally, the tactile warning element 22 can also be designed as a temperature control element or comprise a temperature control element.The warning elements 20, 22 are intended to directly issue warnings or instructions to the wearer of the contact lens 12.

[0030] The integrated output unit 14 comprises a wireless communication device 16. The wireless communication device 16 is integrated into the contact lens 12. The wireless communication device 16 is configured for wireless communication with an external warning system 18. Examples of Fig. 1 shows external warning systems 18, which are designed as a headset system, a smartphone, data glasses, and a smartwatch. However, other alternative external warning systems 18 are also conceivable.

[0031] The contact lens 12 has an integrated power supply 32. The integrated power supply 32 supplies the electrical components of the contact lens 12 with current and voltage. The integrated power supply 32 comprises, for example, a miniature battery / microbattery. The miniature battery / microbattery is designed to be rechargeable. For example, the miniature battery / microbattery can be inductively charged. Alternatively, the integrated power supply 32, and thus the contact lens 12, can also have multiple miniature batteries / microbatteries.

[0032] The integrated power supply 32 is arranged outside a see-through area 34 of the contact lens 12. The integrated blink sensor 10 is arranged outside the see-through area 34 of the contact lens 12. The further integrated blink sensor 24 is arranged outside the see-through area 34 of the contact lens 12. The integrated computing unit 26 is arranged outside the see-through area 34 of the contact lens 12. The integrated output unit 14 is arranged partially outside the see-through area 34 of the contact lens 12. The communication device 16 of the integrated output unit 14 is arranged outside the see-through area 34 of the contact lens 12. The tactile warning element 22 is arranged outside the see-through area 34 of the contact lens 12. The integrated output unit 14 is arranged partially within the see-through area 34 of the contact lens 12.The optical warning element 20 is arranged within the see-through area 34 of the contact lens 12.

[0033] The electronic components of the contact lens 12 are connected to each other by electrical connections 80. The electrical connections 80 are shown in the figure for the sake of simplicity, with the exception of an exemplary electrical connection 80 between the integrated blink sensor 10 and the integrated power supply 32. Fig. 1 not shown.

[0034] The Fig. Figure 2 shows a schematic sectional view of an exemplary embodiment of the integrated blink sensor 10 designed as an acceleration sensor. The integrated blink sensor 10 is formed by a chip scale package (CSP). The integrated blink sensor 10 has a base area 30 of 2 mm 2or less. The integrated blink sensor 10 is designed as a vertically integrated MEMS-ASIC component. The blink sensor 10, which forms an acceleration sensor, is formed by a wafer stack 36. The wafer stack 36 comprises a MEMS wafer 38. The MEMS wafer 38 is manufactured using known surface micromechanical manufacturing methods. The wafer stack 36 comprises an ASIC wafer 40. The ASIC wafer 40 is a CMOS wafer. The ASIC wafer 40 is manufactured using known manufacturing methods in the semiconductor industry. The MEMS wafer 38 contains one or more functional layers, preferably made of silicon, from which conductor tracks, masses, springs, mechanical suspensions, and / or capacitive detection electrodes can be formed. The ASIC wafer 40 contains transistor circuits and rewiring. The MEMS wafer 38 and the ASIC wafer 40 are mechanically and electrically connected to each other via a metallic bonding process.The wafer stack 36 includes a bonding layer 42 which connects the MEMS wafer 38 and the ASIC wafer 40 to each other.

[0035] The bonding layer 42 is preferably produced using a eutectic bonding process, e.g., with aluminum on one wafer 38, 40 and germanium on the other wafer 38, 40. A peripheral frame 44 is arranged in the bonding layer 42. The frame 44 encloses a cavity 46 formed by the mutually facing sides of the MEMS wafer 38 and the ASIC wafer 40. Furthermore, electrical contacts can also be established between the MEMS wafer 38 and the ASIC wafer 40 via the metallic bonding layer 42. A fixed evaluation electrode for detecting movements perpendicular to a wafer plane is optionally arranged in an uppermost metallization layer of the ASIC wafer 40.

[0036] The Fig. The double arrows 48, 50 shown in Figure 2 indicate that a sensor element of the acceleration sensor is laterally and vertically movable. This allows accelerations in the corresponding directions of the double arrows 48, 50 to be detected. The sensor element can be a single movable sensor mass, which can be deflected in multiple directions (xy, xz, or xyz) due to suitable spring geometries. Such a configuration is particularly useful for the application because, due to the resulting maximization of the sensor mass, Brownian noise can be reduced (Brownian noise scales with 1 / root(mass)). Alternatively, however, multiple sensor masses, each deflectable in different directions, can also be provided. The ASIC wafer 40 comprises at least one TSV (Through Silicon Via) 52. The TSV 52 is provided for transmitting signals, e.g., input / output signals, from the ASIC wafer 40.On a side of the ASIC wafer 40 facing away from the MEMS wafer 38, the ASIC wafer 40 has a redistribution layer (RDL). Contact pads 54 for electrically contacting the blink sensor 10 are arranged in the redistribution layer. The redistribution layer is electrically separated from a substrate of the ASIC wafer 40 by one or more passivation layers.

[0037] For integration into the contact lens 12, the height 28 of the blink sensor 10 must be very low. The integrated blink sensor 10 has a height 28 of less than 400 µm. For this purpose, the wafer stack 36, in particular both wafers 38, 40 of the wafer stack 36, are thinned back during production by grinding and / or CMP (chemo-mechanical polishing) processes. In this process, the ASIC wafer 40 is thinned / ground back to a smaller thickness than the MEMS wafer 38. This advantageously allows the TSVs 52 to be produced particularly easily and / or particularly cost-effectively.

[0038] It is obvious that other technical implementations (other wafer stacks, other external contacting, other MEMS processes, etc.) also fall within the scope of the invention. Fig. The construction shown in Figure 2 merely represents a particularly advantageous exemplary embodiment. The additional blink sensor 24, which is intended, for example, for measuring pressure or mechanical stress, can also be implemented as a chip-scale package through vertical integration of MEMS and ASIC wafers. This is described, for example, in the document DE 10 2014 200 512 A1 for a pressure sensor or in the document DE 10 2020 202 277 A1 for a strain sensor. Due to the similarity of the manufacturing technologies to the previously described blink sensor 10 designed as an acceleration sensor, it is possible to integrate the additional blink sensor 24 designed as a pressure sensor and / or as a strain sensor with the blink sensor 10 designed as an acceleration sensor on a common chip.

[0039] The Fig. Figure 3 shows a simplified measurement signal 56 of the eyelid blink sensor 10, which is designed as an acceleration sensor, plotted over time. The wearer of the contact lens 12 is assumed to be at rest in this case, so that the measured acceleration is on average zero (corresponding to a horizontal line). In a first phase 58, the eye of the wearer of the contact lens 12 is open and no blinking occurs. The measurement signal 56 shows no deflections. In a second phase 60 following the first phase 58, the eye fitted with the contact lens 12 blinks. The blink results in a signal amplitude. This signal amplitude is clearly measurable for the eyelid blink sensor 10. The signal amplitude is zero with a double integration over time, since the wearer of the contact lens 12 was assumed to be stationary. Therefore, positive and negative amplitude components will always be observable in the measurement signal 56. The Fig. 3 shown deflections of the measuring signal 56 and the Fig. The blink frequency and blink sequence shown in Figure 3 are intended to represent a state without blink abnormalities. The blink frequency, blink sequence, and blink durations are within the normal range in this example.

[0040] The Fig. 4 shows the measurement signal 56 with a first exemplary signal form different from the normal signal form of the Fig. 3 deviating signal shape. The deviation of the signal shape is caused by an eye blink anomaly. The Fig. Figure 4 shows a multiple blink, i.e. a sequence of at least two, possibly several, blinks in quick succession. Multiple blinks can be an indication of onset of fatigue or drowsiness. Fig. The blinking anomaly shown in Figure 4 may be an indication of a safety-threatening condition when the wearer of the contact lens 12 is performing an activity that requires his full attention.

[0041] The Fig. 5 shows the measurement signal 56 with a second exemplary signal form of the Fig. 3 deviating signal shape. The deviation of the signal shape is caused by an eye blink anomaly. The Fig. Figure 5 shows a significantly slowed eyelid blink. A slowed eyelid blink can also be an indication of the onset of fatigue or drowsiness. The slowed eyelid blink results in smaller acceleration amplitudes in the measurement signal 56, which, however, extend over a longer period. Fig. The blinking anomaly shown in Figure 5 may be an indication of a safety-threatening condition when the wearer of the contact lens 12 is performing an activity that requires his full attention.

[0042] The Fig. 6 shows the measurement signal 56 with a third exemplary signal form different from the normal signal form of the Fig. 3 deviating signal shape. The deviation of the signal shape is caused by an eye blink anomaly. The Fig. Figure 6 shows a measurement signal 56 in which the blink frequency is significantly increased. The increased blink frequency leads to a measurement signal 56 in which the acceleration-free states between the deflections of the measurement signal 56 are significantly shorter compared to the normal state. An increased blink frequency can be an indication of strong tension, high nervousness, and / or a general state of stress. The Fig. The blinking anomaly shown in Figure 6 may be a sign of a health-threatening condition associated with increased stress levels.

[0043] The Fig. 7 shows the measurement signal 56 with a fourth exemplary signal form different from the normal signal form of the Fig. 3 deviating signal shape. The deviation of the signal shape is caused by an eye blink anomaly. The Fig. Figure 7 shows a measurement signal 56 in which the blinking frequency is significantly reduced. The reduced blinking frequency leads to a measurement signal 56 in which the acceleration-free states between the deflections of the measurement signal 56 are significantly longer than in the normal state. Such a slowing of the blinking can occur during long periods of reading or prolonged screen activity. As a result, the eyes can become severely dry and irritated. The Fig. The blinking anomaly shown in Figure 7 may therefore be a sign of a condition that is hazardous to eye health.

[0044] In principle, blink detection could also be performed using a gyroscope or an IMU (Inertial Measurement Unit, i.e., a combined gyroscope and acceleration sensor), since blinking also results in a small rotational movement of the contact lens 12. However, unless the gyroscope is also required for other purposes in the contact lens 12, the acceleration sensor represents the smaller, more cost-effective, and more energy-efficient option.

[0045] The Fig. 8 shows again the already in the Fig. 3 shows the ideal measurement signal 56 of the integrated blink sensor 10 (above), which is designed as an acceleration sensor and occurs during regular blinking. Fig. 8 shows a further measurement signal 62 from the further integrated blink sensor 24 (below), which is embodied, for example, as a pressure sensor (or analogously, as a strain or force sensor). During the eyelid closure of the eye fitted with the contact lens 12, the further measurement signal 62 (pressure signal) from the further integrated blink sensor 24 rises to an elevated level 64, while it remains at a lower level 66 when the eye is open. While the integrated blink sensor 10, embodied as an acceleration sensor, only reacts to eyelid movements, i.e., changes in the eyelid position, the further integrated blink sensor 24, embodied as a pressure sensor (or as a strain or force sensor), provides an indication of the states "eyelid open" versus "eyelid closed." A combination of the two measurement signals 56, 62 with their different signal signatures can now be used to verify the plausibility of the blink detection.This can advantageously reduce the rate of false-positive blink abnormalities. This is particularly evident when considering . Fig. 9 clearly. The Fig. Figure 9 again shows the measurement signal 56 of the integrated blink sensor 10 (top) and the measurement signal 62 of the further integrated blink sensor 24 (bottom). In this case, the eye equipped with the contact lens 12 is open at the beginning of the measurement. Subsequently, the eye equipped with the contact lens 12 is closed and remains closed for a longer period of time. In this case, the measurement signal 56 of the integrated blink sensor 10, which is designed as an acceleration sensor, may not be sufficient to reliably detect that the eye remains closed. Although an acceleration signature of the measurement signal 56 of the integrated blink sensor 10 is different even with a sustained eyelid closure or reopening than with a brief blink, detecting these specific acceleration signatures can be challenging, complex, and / or unreliable.The additional measurement signal 62 from the additional integrated blink sensor 24, designed as a pressure sensor, provides a clear indication of the prolonged eyelid closure. The comparison of the two measurement signals 56, 62 can now be used to perform a plausibility check of the individual signals. In particular, the additional measurement signal 62 can now be used to verify / confirm a deflection of the measurement signal 56 that is recognized as a blink.

[0046] The Fig.10 shows a schematic flow diagram of a method using the contact lens 12. In the method, the eyelid blink sensor 10, which is designed as an acceleration sensor and integrated into the contact lens 12, detects a safety- and / or health-relevant blinking anomaly of an eyelid of an eye of a wearer of the contact lens 12. In at least one method step 68, the contact lens 12 is inserted into the wearer's eye. In at least one method step 70, the measurement signal 56 of the integrated eyelid blink sensor 10 is acquired. In at least one method step 72, the further measurement signal 62 of the further integrated eyelid blink sensor 24 is acquired. In at least one method step 74, the acquired measurement signal 56 of the integrated eyelid blink sensor 10 is examined for signatures that indicate a safety- and / or health-relevant blinking anomaly.In at least one method step 76, the plausibility of an eyelid blink anomaly detected from the measurement signal 56 of the integrated eyelid blink sensor 10 is checked by comparing it with the further measurement signal 62 of the further integrated eyelid blink sensor 24. In at least one method step 78, in particular depending on a confirmation of the plausibility, a warning signal is triggered by the output unit 14 integrated into the contact lens 12 and / or output, in particular to the wearer of the contact lens 12. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 9,671,619 B2

[0001] US 2017 / 0023793 A1

[0001] US 10,444,541 B2

[0001] US 2017 / 0031159 A1

[0001] US 2017 / 0354326 A1

[0001] US 4,349,724 A

[0001] EP 3 338 623 A1

[0001] US 2015 / 0257699 A1

[0001] DE 10 2014 200 512 A1

[0038] DE 10 2020 202 277 A1

[0038] Zitierte Nicht-Patentliteratur

[0000] Morris und Miller, „Electrooculographic and performance indices of fatigue during simulated flight“, Biol Psychol 1996, 42, S. 343-360

[0005] Caffier et al., „Experimental evaluation of eye-blink parameters as a drowsiness measure“, Eur J Appl Physiol 2003, 89, S. 319-325

[0005] Wilkinson et al., „The Accuracy of Eyelid Movement Parameters for Drowsiness Detection“, J. Clinical Sleep Medicine 2013, Vol 09, Issue 12, S. 1315-1324

[0005]

Claims

[1] Contact lens (12), with at least one integrated blink sensor (10) at least for detecting a safety- and / or health-relevant blink anomaly of an eyelid of a wearer of the contact lens (12), and with at least one integrated output unit (14) which is configured to trigger and / or output a warning signal, wherein the integrated blink sensor (10) is designed as an acceleration sensor. [2] Contact lens (12) according to claim 1, characterized by that the blinking anomaly detectable by the blink sensor (10) is designed as an increased or decreased blinking frequency compared to a normal state, for example about 10 blinks per minute, and / or as an eyelid blink sequence representing an indicator of the presence of an anomaly, such as fatigue. [3] Contact lens (12) according to claim 1 or 2, characterized bythat the blinking anomaly detectable by the blink sensor (10) is a deviation from an average blinking duration. [4] Contact lens (12) according to one of the preceding claims, characterized by in that the integrated output unit (14) comprises a wireless communication device (16) which is particularly designed for communication with an external warning system (18), such as a smartphone, data glasses, a headphone system or a smartwatch. [5] Contact lens (12) according to one of the preceding claims, characterized by that the integrated output unit (14) comprises an optical warning element (20), such as a micro-LED, and / or a tactile warning element (22), such as a vibrator or a tempering element. [6] Contact lens (12) according to one of the preceding claims, characterized bya further integrated blink sensor (24) which is based on a measuring principle that is different from a measuring principle of the blink sensor (10). [7] Contact lens (12) according to claim 6, characterized by that the further integrated blink sensor (24) is designed as a pressure sensor, as a rotation rate sensor, as a strain sensor or as a combination of at least two of these three sensor types. [8] Contact lens (12) according to claim 6 or 7, characterized by an integrated computing unit (26) which is configured to carry out a plausibility check of eyelid blink measurement results and / or eyelid position measurement results based on a comparison of measurement signals (56, 62) of the integrated eyelid blink sensor (10) and the further integrated eyelid blink sensor (24). [9] Contact lens (12) according to claim 8, characterized bythat the integrated computing unit (26) is designed to initiate or permit the output of a warning signal via the integrated output unit (14) only if there is a positive result of the plausibility check of the underlying measurement signals (56, 62). [10] Contact lens (12) according to one of the preceding claims, characterized by that the integrated blink sensor (10) has a height (28) of less than 400 µm. [11] Contact lens (12) according to one of the preceding claims, characterized by that the integrated blink sensor (10) has a base area (30) of 2 mm 2 or less. [12] Contact lens (12) according to one of the preceding claims, characterized by that the integrated blink sensor (10) is designed as a vertically integrated MEMS-ASIC component. [13] Contact lens (12) according to one of the preceding claims, characterized bythat the integrated blink sensor (10) is formed by a chip scale package (CSP). [14] Method with a contact lens (12), in particular according to one of the preceding claims, wherein a safety- and / or health-relevant blinking anomaly of an eyelid of a wearer of the contact lens (12) is detected by an eyelid blink sensor (10) designed as an acceleration sensor and integrated into the contact lens (12), and wherein a warning signal is triggered and / or output by an output unit (14) integrated into the contact lens (12).

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