Patent Publication Number: US-11022819-B2

Title: Lens-to-lens communication for contact lenses

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 14/873,025, filed on Oct. 1, 2015, the contents of which are herein incorporated by reference. The present application is also related to a U.S. application Ser. No. 14/873,034, also filed on Oct. 1, 2015. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to contact lenses, and in particular to communication between contact lenses. 
     BACKGROUND INFORMATION 
     Contact lenses have been developed that include on-board measurement sensors. When worn by a user, contact lenses have access to measure biometric data through the tear solution of the eye, for example. Contact lenses are also in position to measure a gaze direction of a user. In certain contexts, it is desirable for data from the measurements to be accessible by the contact lens worn in the opposite eye. Other contact use cases would also benefit from lens-to-lens communication between contact lenses. However, conventional technologies generally require the user/wearer to manually bring additional hardware into proximity with a pair of contacts to share data between contact lenses. Having additional hardware required for lens-to-lens communication reduces the contexts and functionality of contact lenses that would benefit from lens-to-lens communication. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  illustrates a user wearing a pair of contact lenses that form a lens-to-lens communication system, in accordance with an embodiment of the disclosure. 
         FIG. 2  illustrates a block diagram schematic that includes contact lenses having transmission and reception circuitry for lens-to-lens communication, in accordance with an embodiment of the disclosure. 
         FIG. 3A  illustrates one example of blink detection circuitry that includes a photodiode, in accordance with an embodiment of the disclosure. 
         FIG. 3B  illustrates one example of data transmission circuitry for a contact lens, in accordance with an embodiment of the disclosure. 
         FIG. 3C  illustrates one example of data reception circuitry for a contact lens, in accordance with an embodiment of the disclosure. 
         FIG. 4A  illustrates a top view of an example contact lens for lens-to-lens communication, in accordance with an embodiment of the disclosure. 
         FIG. 4B  illustrates a side view of the example contact lens of  FIG. 4A , in accordance with an embodiment of the disclosure. 
         FIG. 5  illustrates a flow chart for an example process of lens-to-lens communication, in accordance with an embodiment of the disclosure. 
         FIG. 6  illustrates a flow chart for an example process of detecting eye convergence using lens-to-lens communication, in accordance with an embodiment of the disclosure. 
         FIG. 7  illustrates a second flow chart for an example process of detecting eye convergence using lens-to-lens communication, in accordance with an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of a system and method of lens-to-lens communication with contact lenses are described herein. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
       FIG. 1  illustrates a user  199  wearing a pair of contact lenses that form a lens-to-lens communication system, in accordance with an embodiment of the disclosure. User  199  is wearing a pair of contact lenses that includes a right contact lens  150 A and a left contact lens  150 B. Contact lenses  150 A and  150 B communicate by using biopath  133  as a signal path for low power signals. This disclosure describes lens-to-lens communication between contact lenses and also describes certain use cases for lens-to-lens communication. In some cases, the lens-to-lens communication will be during a blinking of eyes of user  199 . A blink of a human eye typically is not less than 100 ms. Blinking is typically synchronized in that both eye blink at the same time. Hence, a detection of a blink can be an advantageous time to establish a reference time for data transmission between contact lenses. 
       FIG. 2  illustrates a block diagram schematic of a system  200  that includes contact lenses  150 A and  150 B. In  FIG. 2 , contact lenses  150  include logic engine  225 , data transmission circuitry  235 , data reception circuitry  240 , blink detection circuitry  231 , and gaze detection circuitry  232 . Not all embodiments will necessarily include all of the elements illustrated in contact lenses  150 . 
     Logic engine  225  may include a microprocessor, a Field Programmable Gate Array (“FPGA”), or other discrete logic. Logic engine  225  may be fabricated utilizing CMOS processing techniques into a semiconductor substrate of contact lens  150 . Logic engine  225  may include memory to store settings, instructions, and/or data received from circuitry of contact lens  150 . Logic engine  225  is coupled to receive a blink signal from blink detection circuitry  231 . Blink detection circuitry  231  is configured to generate the blink signal in response to an eye blinking or closing (when contact  150  is inserted into an eye). Logic engine  225  is also coupled to receive an inward gaze signal from gaze detection circuitry  232 . Gaze detection circuitry is configured to generate an inward gaze signal in response to an eye looking inward (when contact  150  is inserted into an eye). Looking “inward” is looking inward toward the nose of a wearer of contact lens  150 . 
     Logic engine  225  is configured to cause data transmission circuitry  235  to drive electrical signals onto electrode  261  in response to the blink signal from blink detection circuitry  231  reaching a pre-determined threshold.  FIG. 3A  illustrates blink detection circuitry  310  that could be used as blink detection circuitry  231 , in accordance with an embodiment of the disclosure. Blink detection circuitry  310  includes a photodiode or photosensor  371 , amplifier  373 , and output node  375 . Amplifier  373  generates the blink signal on node  375  in response to a current generated by photodiode  371  in response to ambient light  377  incident on photodiode  371 . The blink signal increases when the incident ambient light  377  increases in intensity and the blink signal decreases when incident ambient light  377  decreases, in  FIG. 3A . When a wearer of contact  150  closes the eye that the contact  150  is worn in, the photodiode will receive very little (if any) ambient light  377 . In one embodiment, logic engine  225  causes data transmission circuitry  235  to send the electrical data signals when a voltage on node  375  falls below a pre-determined threshold and recovers above the pre-determined threshold under a pre-determined amount of time (e.g. 400 ms) that would signify a blink. 
     In another embodiment, blink detection circuitry  231  includes sensing electrodes that are exposed to be contacted by an eyelid when an eye blinks, but the sensing electrodes are not contacted by the eyelid when the eye is open (viewing the world). In this embodiment, logic engine  225  measures an electrical impedance between the sensing electrodes to detect an eye blink. When the eyelid is open, the electrical impedance magnitude between the sensing electrodes will be very high (open circuit) since the eyelid will not be contacting the sensing electrodes. The eyelid closing will put a measureable electrical impedance across the sensing electrode as the eyelid contacts both sensing electrodes and closes the circuit. 
     When logic engine  225  detects that the eye has closed, it drives data transmission circuitry  235  to transmit electrical data signals onto electrode  261  and ultimately through biopath  133 . The electrical data signals are short pulses, in one embodiment. In one embodiment, the pulses are 400 mV and 10 ns in duration. A variety of different communication protocols can be utilized to communicate data between contacting lenses using low voltage pulses as bits. 
       FIG. 3B  illustrates one example of data transmission circuitry  320  for a contact lens, in accordance with an embodiment of the disclosure. Data transmission circuitry  320  is one example of data transmission circuitry  235 . Data transmission circuitry  320  is a transmitter for Binary phase-shift keying (“BPSK”) signaling. It is appreciated that data transmission circuitry  235  may be incorporated into logic engine  225 , in some embodiments. 
     Data transmission circuitry  320  includes programmable delays  386  and  387 , AND gate  393 , 2:1 multiplexors  391  and  392 , programmable gain amplifiers  381  and  382 , capacitors  383  and  384 , and resistor  385 . Symbol CLK  388  is a clock coming in at the pulse repetition frequency, or whenever a pulse is required. The pulse is generated at the output of AND gate  393  at the rising edge of symbol CLK  388 . At every positive edge of symbol CLK  388 , a pair of antipodal pulses is generated at terminal  261 . The first programmable delay  387  on the left dictates the width of a pulse within a pair of pulses. One pair of antipodal pulses is equivalent to one pulse bit symbol signal. This can be a delay line created with a cascade of a current starved inverter. The second programmable delay  386  dictates the pulse separation time between pulses within a symbol. This depends on the typical channel impulse response, and can be programmed so that there is no inter-pulse interference within a symbol. Muxes  391 / 392  take as inputs different types of pulses: the upper mux  392  is responsible for selecting the sign of the first pulse in a pair of pulses that forma a bit symbol, and the lower mux  391  is responsible for selecting the sign of the second pulse in a pair of pulses that form a bit. 
     The programmable gain stages  381 / 382  allow the digital pulses that come out of muxes  391 / 392  to be converted to analog, and these stages dictate the amplitude of the pulses. Capacitors  383 / 384  are summing capacitors that combine the two pulses differing in time and sign to terminal  261 . Resistor  385  is a large resistor that sets the DC bias of terminal  261  to zero. The pulses are generated in pairs of pulses, the pulses are opposite in sign, and carry zero net charge over the symbol (resistor to ground and equivalent but opposite in sign pulses going into the capacitors  383 / 384  will ensure that). Logic engine  225  is coupled to muxes  391 / 392 . By driving a digital high or low onto muxes  391 / 392 , logic engine  225  can generate positive or negative pulses. 
     In one embodiment, electrode  261  is disposed to come in contact with a tear film of an eye to transmit electrical data signals. In one embodiment, electrode  261  is encapsulated within a contact lens and disposed to be capacitively coupled to transmit electrical data signals to a tear solution of the eye. Electrode  263  may be encapsulated within a contact lens and disposed to be capacitively coupled to receive a raw data signal from a tear solution of the eye or disposed to come in contact with the tear film to receive the raw data signal. 
     The electrical data signals travel from electrode  261  through biopath  133  to reach data reception circuitry  240 B via electrode  263 . Biopath  133  includes biological matter disposed between the human eye and in particular the biological matter in the path between electrodes  261  and  263 . 
       FIG. 3C  illustrates one example of data reception circuitry for a contact lens, in accordance with an embodiment of the disclosure. Data reception circuitry  330  is one example of data reception circuitry  240 . Data reception circuitry  330  is a receiver for BPSK signaling. Data reception circuitry  330  includes low-noise-amplifier (LNA)  336 , windowed integrators  353 , Analog-to-Digital Converters (“ADCs”)  356 , and Digital Engine  359 . Windowed integrators  353 , Analog-to-Digital Converters (“ADCs”)  356 , and Digital Engine  359  may be considered to form a mixed-signal correlator. The electrical data signals driven onto electrode  261  are received as raw data signals at electrode  263  and LNA  336 . LNA  336  amplifies the raw data signal into an amplified data signal  337 . Interleaved windowed integrators  353  shuffle and integrate the LNA output  337  onto a bank of integrating capacitors (not illustrated) whose structure and multiplicity (number of windowed integrators that will be shuffled in/out) will be optimized for efficiency and power. ADCs  356  are coupled to sample the analog integration value to digital and Digital Engine  359  generates output data  339  by performing timing, channel, and bit recovery on the digital outputs of ADCs  356 . In one embodiment, an inverse transform is performed to reconstruct the electrical data signal(s) that was driven onto electrode  261 . The inverse transform of the amplified data signal  337  may be informed by an impedance-based channel modeling of biopath  133 . 
     In the illustrated embodiment of system  200 , each contact lens has both data transmission circuitry  235  and data reception circuitry  240  to enable bi-directional communication. However, in one embodiment of system  200 , one contact lens (e.g. lens  150 A) has data transmission circuitry  235 , but not data reception circuitry  240  and the other contact lens (e.g. lens  150 B) has data reception circuitry  240 , but not data transmission circuitry  235 . In this embodiment, the communication between contact lenses in unidirectional. 
       FIG. 4A  illustrates a top view of a contact lens  410  that includes logic engine  225 , data transmission circuitry  235 , data reception circuitry  240 , blink detection circuitry  231 , and gaze detection circuitry  232 , in accordance with an embodiment of the disclosure. Contact lens  410  is one example of contact lenses  150 . Contact lens  410  includes transparent material  421  that is made from a biocompatible material suitable for a contact lens. In one embodiment, the contact lens includes a silicone elastomer. In one embodiment, the contact lens includes hydrogel. Substrate  430  is illustrated as a substantially flattened ring disposed atop or embedded within transparent material  421 . In one embodiment, the flattened ring has a diameter of about 10 millimeters, a radial width of about 1 millimeter, and a thickness of about 50 micrometers. 
     Substrate  430  includes one or more surfaces for mounting elements such as logic engine  225 , data transmission circuitry  235 , data reception circuitry  240 , blink detection circuitry  231 , and gaze detection circuitry  232 . In one embodiment, substrate  430  includes a semiconductor material (e.g. silicon) and logic engine  225  is formed in substrate  430  by way of common CMOS processes. In one embodiment, substrate  430  includes a multi-layer flexible circuit board. In one embodiment, substrate  430  is made of a rigid material such as polyethylene terephthalate (“PET”). In one embodiment, substrate  430  is made of flexible material such as polyimide or organic material. Substrate  430  may be disposed along an outer perimeter of contact lens  410  so as not to interfere with a viewable region of contact lens  410  that a wearer of contact lens  410  would be looking through. However, in one embodiment, substrate  430  is substantially transparent and does not substantially interfere with a wearer&#39;s view, regardless of disposition location. 
     In  FIG. 4A , blink detection circuitry  231  (which may include a photodiode) is disposed in substrate  430  in a middle band of lens  410  such that when a wearer of lens  410  is viewing the world, the blink detection circuitry (and included photodiode) is exposed to ambient light. When the eye blinks, it covers blink detection circuitry  231 , which changes the blink signal generated by blink detection circuitry  231 . Contact lens  410  may be weighted (similar to contacts designed to correct astigmatism) to keep certain elements of contact lens  410  in their relative spatial orientations relative to the eye. 
     In  FIG. 4A , gaze detection circuitry  232  is also disposed in substrate  430  and positioned in the middle band of contact lens  410 . In addition, gaze detection circuitry  232  may be positioned closest to the nose of a wearer of lens  410 . In one embodiment, gaze detection circuitry  232  includes a photodiode or an array of photodiodes. When an eye looks inward to focus at a near object/person/place, a photodiode included in gaze detection circuitry  232  may become covered by the eyelid, which changes a signal generated by the photodiode. In one embodiment, gaze detection circuitry  232  is similar to circuitry  310 . In one embodiment, gaze detection circuitry  232  and blink detection circuitry  231  share electrical components, such as photodiodes. In other words, an array of photodiodes could be utilized to detect both blinking and inward gaze events. The electrical impedance scheme described above in association with blink detection circuitry  231  may also be utilized as gaze detection circuitry  232  to determine when the eye is gazing inwardly. As will be described in more detail below, detecting an inward gaze of the eye can be useful in adjusting an optical power for the eye to assist in near-field focusing. 
     Still referring to  FIG. 4A , data transmission circuitry  235  is coupled to one or more electrodes  460  to send out electrical data signals onto the tear solution of the eye. Data reception circuitry  240  is also coupled to one or more electrodes  460  to receive the electrical data signals from the tear solution of the eye. The quantity and placement of electrodes will vary depending on whether a larger signal transmission/receptions is required, the ability to beamform the transmitted and received pulse path, whether the electrodes can be reused for impedance sensing, and the data protocol utilized. In one embodiment, only one electrode (e.g.  261 ) is used to drive the electrical data signals. In one embodiment, only one electrode (e.g.  263 ) is used to receive the electrical data signals as raw data signals from data transmission circuitry  235 . 
       FIG. 4B  illustrates a side view of contact lens  410  that includes logic engine  225 , data transmission circuitry  235 , data reception circuitry  240 , blink detection circuitry  231 , and gaze detection circuitry  232 , in accordance with an embodiment of the disclosure.  FIG. 4B  shows transparent material  421  has a concave surface side  426  (eyeside) opposite a convex surface side  424  (external side). Concave surface side  426  will have substantial contact with the eye of a wearer of lens  410 . A circular outside edge  428  connects concave surface side  426  and convex surface side  424 . In  FIG. 4B , a photodiode in blink detection circuitry  231  or gaze detection circuitry  232  will face outward so that it can measure ambient scene light. Any terminals to measure electrical impedance will be disposed on the external side  424  lens  410  in order to sense any eyelid covering contact  410  (in contrast to eyeside  426 , which will be constantly contacting the eye). Electrode  460  and additional electrodes (not illustrated) are disposed on the eyeside of contact lens  410  so that the electrodes contact the tear film of the eye and thus access biopath  133 . 
       FIG. 5  illustrates a flow chart for an example process  500  of lens-to-lens communication, in accordance with an embodiment of the disclosure. The order in which some or all of the process blocks appear in process  500  should not be deemed limiting. Rather, one of ordinary skill in the art having the benefit of the present disclosure will understand that some of the process blocks may be executed in a variety of orders not illustrated, or even in parallel. 
     In process block  505 , an eye blink is detected with blink detection circuitry (e.g.  231 A) included in a first contact lens (e.g. lens  150 A). Electrical power for data transmission circuitry may be activated by in response to detecting the eye blink, in process block  510 . Providing electrical power to data transmission circuitry  235  only after a blink is detected may save power compared to powering data transmission circuitry at all times. In process block  515 , data is transmitted from the first contact lens (e.g. lens  150 A) to a second contact lens (e.g.  150 B) in response to detecting the eye blink. The data may take the form of electrical pulses that communicate digital words. The data is received with data reception circuitry (e.g.  240 B) of the second contact lens (e.g.  150 B) in process block  520 . An optical power for the second eye is adjusted in response to the data in process block  525 . 
       FIG. 6  illustrates a flow chart for an example process  600  of detecting eye convergence using lens-to-lens communication, in accordance with an embodiment of the disclosure. The order in which some or all of the process blocks appear in process  600  should not be deemed limiting. Rather, one of ordinary skill in the art having the benefit of the present disclosure will understand that some of the process blocks may be executed in a variety of orders not illustrated, or even in parallel. 
     In process block  605 , a first inward gaze is detected with first gaze detection circuitry (e.g. circuitry  232 A) included in a first contact lens (e.g. lens  150 A). In process block  610 , a first inward gaze signal is transmitted from the first contact lens to a second contact lens (e.g.  150 B) in response to detecting the first inward gaze. The first inward gaze signal may be a digital word sent in the form of voltage pulses via biopath  133  to the second contact lens. The first inward gaze signal may be sent by data transmission circuitry  235 A, for example. A second inward gaze is detected with second gaze detection circuitry (e.g. circuitry  232 B) included in the second contact lens, in process block  615 . In process block  620 , the second contact lens receives the first inward gaze signal from the first contact lens. The first inward gaze signal may be received by reception circuitry  240 B, for example. An optical power for the second eye is adjusted when the first inward gaze signal is received within a pre-determined time period (e.g. 50 ms) from detecting the second inward gaze with the second gaze detection circuitry. The optical power may be changed by adjusting a control signal (e.g. voltage(s) signal) on a liquid crystal lens. The liquid crystal lens may be integrated into a contact lens, for example. 
       FIG. 7  illustrates a second flow chart for an example process  700  of detecting eye convergence using lens-to-lens communication, in accordance with an embodiment of the disclosure. Process  600  illustrates a unidirectional communication process while process  700  illustrates a bi-directional communication process. The order in which some or all of the process blocks appear in process  700  should not be deemed limiting. Rather, one of ordinary skill in the art having the benefit of the present disclosure will understand that some of the process blocks may be executed in a variety of orders not illustrated, or even in parallel. 
     In process block  705 , inward gaze detection circuitry (e.g. circuitry  232 B) is sampled for a left inward gaze signal. Process block  705  is executed until the left inward gaze signal is detected. In one example, a left inward gaze signal is detected when an output of a photodiode drops below a given threshold for a particular amount of time, which indicates that the photodiode is covered by an eyelid and thus, the left eye is looking inward and the wearer of the contact lens desires to focus on a near object (e.g. reading a book). If a left inward gaze is detected, process  700  proceeds to process block  710 . 
     In process block  710 , data transmission circuitry (e.g.  235 B) is prepared to send an inward gaze signal to the right contact (e.g. lens  150 A) via bio path  133 . Preparing the data transmission circuitry may include powering up the data transmission circuitry and preloading it with the data (e.g. digital data) to be transmitted. Leaving the data transmission circuitry off except for when it is actually needed to transmit data will save power for executing other functions of the contact lens. If there is no blink within a time period T 1  (e.g. 0.5 s), process  700  returns to process block  705 . In one use context, the wearer of contact lenses  150 A and  150 B signals to the contact lenses that the user would like to adjust an optical power for their eyes by blinking soon after looking inward. This allows the contact lens to detect both the user looking inward and then blinking soon afterwards as a signal that the contact lens should initiate an optical power adjustment to facilitate near-field focus, for example. 
     If there is a blink detected within time period T 1 , process  700  proceeds from process block  710  to process block  715 . In process block  715 , the left inward gaze signal is transmitted to the right contact (e.g. lens  150 A) via biopath  133 . Also in process block  715 , data reception circuitry  240  listens for a right inward gaze signal from the right contact. If the right inward gaze signal (acknowledgment) is not received by the left contact lens within a time period T 2  (e.g. 200 ms), process  700  returns to process block  705 . However, if right inward gaze signal (acknowledgment) is received by the left contact lens within time period T 2 , process  700  proceeds to process block  720  to adjust an optical power for the left eye. 
     When process block arrives at process block  720 , a left inward gaze has been detected by the left contact lens and the left contact lens has received an acknowledgment (the right inward gaze signal) that the right contact has also detected a right inward gaze. Hence, the conclusion is that the left eye and the right eye are converging by both looking inward. The left contact has also received confirmation that the wearer of the contacts would like their optical power adjusted by way of detecting a blink within time T 1  of detecting the left inward gaze. Process blocks  725 ,  730 ,  735 , and  740  are similar (except adjusted to the right contact) to process blocks  705 ,  710 ,  715 , and  720 , respectively. 
     The processes explained above are described in terms of computer software and hardware. The techniques described may constitute machine-executable instructions embodied within a tangible or non-transitory machine (e.g., computer) readable storage medium, that when executed by a machine will cause the machine to perform the operations described. Additionally, the processes may be embodied within hardware, such as an application specific integrated circuit (“ASIC”) or otherwise. 
     A tangible non-transitory machine-readable storage medium includes any mechanism that provides (i.e., stores) information in a form accessible by a machine (e.g., a computer, network device, personal digital assistant, manufacturing tool, any device with a set of one or more processors, etc.). For example, a machine-readable storage medium includes recordable/non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.). 
     The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. 
     These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.