Patent Publication Number: US-2018043646-A1

Title: Method of power transmission to contact lens and system using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from Taiwan Patent Application No. 105125559 filed on Aug. 11, 2016, which are hereby incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a contact lens capable of receiving electrical energy from its exterior, and particularly, to a method of power transmission to a contact lens and a system using the same. 
     2. Description of Related Art 
     A contact lens is a lens placed on the cornea of an eye for vision correction or eye protection. When the miniature technology of electrical devices has been gradually mature, a contact lens is used not only to correct vision but also to sense the physical properties of an eye or mechanical substances in tears by a miniaturized electrical device which is embedded into the contact lens. Thus, a user can understand the health of his eyes or body. For example, a control circuit, a microprocessor, a communication device, a power supply, a sensor, an actuator, an LED, a photoelectrical sensor, or a miniaturized antenna is integrated with a contact lens so that the contact lens can be used to correct vision and further improve vision. Furthermore, it can yield additionally functional results. 
     The foregoing miniaturized electrical device needs to consume electrical power for its normal operation. Accordingly, it is an important and unresolved problem that sufficient electrical power is effectively supplied to the contact lens. For example, U.S. publication patent application US2013/0041245 A1 disclosed an assembly of a contact lens and a pressure sensor capable of long-termly measuring intraocular pressure. The assembly embeds a resistance pressure sensor, an antenna, and a sensing chip into the contact lens. Such assembly of the contact lens is worn on the cornea of an eye. The electrical power is transmitted to the assembly of the contact lens by near field coupling. Accordingly, an antenna capable of transmitting data and electrical power is attached to the surrounding (i.e. an eye socket) of an eye for a tester. Moreover, the antenna is in electrical communication with a portable record apparatus by an electrical wire, and is capable of being powered by the portable record apparatus to generate an electromagnetic field with sufficient sensitivity. Thus, a required coupling current is induced in the antenna of the contact lens. However, when the apparatus and the antenna mounted to the eye socket simultaneously operate, the surrounding of the eye of the tester exists in the electromagnetic field with a certain power density so that a chronic injury is caused to the delicate eye. Furthermore, the electrical wire wraps tester&#39;s body so that he moves with some difficulty. 
     Also, U.S. Pat. No. 8,096,654 B2 disclosed a contact lens whose interior has an image display, several processing chips, an energy transfer antenna, and biosensors. In addition to the contact lens, a radio frequency communication apparatus and a power supply apparatus are necessarily provided at a far side. Such a contact lens can be applied to image display, biomedical sensing or related uses. It consumes the power externally from the power supply apparatus which electrically powers the contact lens in a far-field transferring energy way. Likewise, a tester needs to wear an additional apparatus, and exists a high power electromagnetic environment so that his eye and body may have quite injuries. 
     In view of above, the users are in very need of a safe and compact energy transfer apparatus capable of energy harvest (harvesting energy from the external of the system or apparatus and transferring it to electrical energy) and a contact lens with circuits which simultaneously operate. It can be broadly applied to preventive medicine and correctional health. 
     SUMMARY OF THE INVENTION 
     The present application provides a method of power transmission to a contact lens and a system using the same. Electrical energy is generated to power electrical components within a contact lens by physical motion based on the electromagnetic induction theory. 
     In view of above aspects, the present invention provides a system of power transmission to a contact lens which comprises a contact lens comprising at least a physiological signal sensing component, an induction coil, and an energy storage component electrically connected to the physiological signal sensing component and the induction coil; and a magnetic component, wherein an induction electromotive force is produced in the induction coil for charging the energy storage component when the magnetic component has a motion relative to the induction coil. 
     In an embodiment, the magnetic component comprises a material capable of generating magnetic lines. The magnetic component is disposed on the surface of an upper lid. 
     In an embodiment, the contact lens comprises a transparent material. The physiological signal sensing component, the induction coil, and the energy storage component are embedded into the transparent material. 
     In an embodiment, the induction coil is an antenna for transmitting wireless signals. The system comprises a receiving analyzer for receiving and analyzing the wireless signals from the antenna. 
     In an embodiment, the physiological signal sensing component is used to measure the intraocular pressure, humidity, temperature, pH, or the composition of tears for an eye. The contact lens further comprises a power management circuit. The power management circuit conducts rectification, voltage limitation, and voltage stabilization (regulation) for the induction electromotive force, and stores processed electrical energy in the energy storage component. 
     In an embodiment, the contact lens further comprises a transceiver and processer circuit including: a signal reading circuit capturing electrical signals generated from the physiological signal sensing component; a processor converting the electrical signals into processed signals; a modulator adapting the impedance of the induction coil to control the induction coil for generating the induction electromotive force, receiving high frequency wireless signals from an exterior or transmitting wireless signals to the exterior or being capable of converting the processed signals into high frequency wireless signals for feeding the induction coil them to transmit outwardly; and a demodulator receiving the high frequency wireless signals received by the induction coil from the exterior and recovering the high frequency wireless signals to low frequency signals for transmitting them to the processor. 
     In an embodiment, the energy storage component is a capacitor, an inductor, or a battery. 
     The present invention further provides a method for transmitting electrical energy to a contact lens comprising the steps of: providing a contact lens with an induction coil and a magnetic component; and moving the magnetic component relative to the induction coil in a manner that an induction electromotive force is produced in the induction coil. 
     The present invention provides a system of power transmission to a contact lens which comprises a contact lens comprising at least a physiological signal sensing component and an induction coil; and a magnetic component, wherein an induction electromotive force is produced in the induction coil for powering the physiological signal sensing component when the magnetic component has a motion relative to the induction coil. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to sufficiently understand the essence, advantages and the preferred embodiments of the present invention, the following detailed description will be more clearly understood by referring to the accompanying drawings. 
         FIG. 1  is a schematic diagram of a contact lens in accordance with an embodiment of the present application; 
         FIG. 2  is a schematic diagram of a magnetic component in accordance with an embodiment of the present application; 
         FIG. 3A  and  FIG. 3B  illustrate a schematic diagram of the contact lens of  FIG. 1  worn on the surface of an eye and the magnetic component of  FIG. 2  attached to an upper lid; 
         FIG. 4A  and  FIG. 4B  illustrate the magnetic component having a motion relative to the induction coil in accordance with an embodiment of the present application; 
         FIG. 5  is the function block diagram of a circuitry within a contact lens in accordance with an embodiment of the present invention; 
         FIG. 6  is a schematic diagram of a system of power transmission to a contact lens in accordance with another embodiment of the present invention; 
         FIG. 7  is the function block diagram of a circuitry within a contact lens in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description shows the preferred embodiments of the present invention. The present invention is described below by referring to the embodiments and the figures. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the principles disclosed herein. Furthermore, that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. 
       FIG. 1  is a schematic diagram of a contact lens in accordance with an embodiment of the present application. This embodiment illustrates a contact lens  10  with a temperature measurement function, but the application is not limited to this example. The concept may be applied to any wearable apparatus on the surface of an eye. The contact lens  10  mainly comprises a transparent substrate  11 , a physiological signal sensing component (or a physiological signal sensing system)  12 , an induction coil (or an antenna)  13  and a transceiver and processer circuit  14 . The material of the transparent substrate  11  may be silicone hydrogel (e.g. Hydroxyethyl methacrylate (HEMA)) which has the advantages of high levels of oxygen permeability and hydrophily. Therefore, a user can feel more comfortable with the contact lens within a long period. The material of the transparent substrate  11  can be other transparent polymer materials, but is not limited to the example. The induction coil  13  can transmit wireless signals outwards and also can receive external energy. For example, magnetic induction is produced by an external magnetic component in the induction coil  13  so that electrical energy which is accordingly generated powers the physiological signal sensing component  12  and a transceiver and processer circuit  14 . The electrical energy may be directly or indirectly (e.g. through a power management circuit) supplied to the two components. More detailed explanations are described in the embodiments below. 
     The physiological signal sensing component  12  may an ASIC (Application-Specific IC), a MEMS device, or a sensing device formed by a nano or peco chemical material, metal material or bio material. They can be used to measure the intraocular pressure, humidity, temperature, pH, or the composition (e.g. blood glucose) of tears. Various sensors with different uses or types may be applied to the embodiment, and include active devices and passive devices. The former ones including active circuits consume more power, and the later ones consume quite less power. The sufficient power is provided to the devices based on their requirements, and otherwise, the devices cannot read sensing signals or normally perform. The transceiver and processer circuit  14  can convert the electrical signals (e.g. voltage signals or current signals) generated from the physiological signal sensing component  12  to radio frequency (RF) signals, and wireless signals are transmitted outwards by the antenna  13 . The application is not limited to the conversion from the electrical signals to the RF signals. The electrical signals may be converted to signals Bluetooth conforming to Bluetooth or WiFi protocols. Similar to the foregoing ring-like wirings, the antenna  13  is coated on the surface of the transparent substrate  11  and disposed outside the temperature sensing device as several ring-like wirings. It transmits wireless signals conforming to a communication protocol outwards. 
     The foregoing magnetic component comprises a material capable of generating magnetic lines. Therefore, the induction coil  13  cuts the magnetic lines, and an induction electromotive force is produced in the induction coil  13 . The induction coil  13  is made in an electrically close loop so that an induced voltage is accordingly produced by the induction electromotive force.  FIG. 2  is a schematic diagram of a magnetic component in accordance with an embodiment of the present application. A magnetic component  20  includes an N pole  21  and S pole  22 . The magnetic lines leave from the N pole  21 , go through ambient air, and come in the S pole  22 . Then, the lines pass the interior of the magnetic component  20  and reach the N pole  21  repeatedly. 
       FIG. 3A  and  FIG. 3B  illustrate a schematic diagram of the contact lens of  FIG. 1  worn on the surface of an eye and the magnetic component of  FIG. 2  attached to an upper lid. As shown in  FIG. 3A , when an eye is open, the magnetic component  20  is attached to an upper lid and is above the upper rim of the contact lens  10  worn on an eyeball  80 . The magnetic component  20  and the contact lens  10  are included in a system  30  for transmitting electrical energy to a contact lens. A normal person blinks about dozens of times per minute when awake. The upper lid moves towards the lower lid till they are temporally close or near during each blink. Therefore, the magnetic lines of the magnetic component  20  attached to the upper lid cross the induction coil  13 , and are cut by the induction coil  13 . Accordingly, an induction electromotive force is produced in the induction coil  13 . Afterward the upper lid is away from the lower lid toward the upper portion of the eyeball  80 . Similarly, the magnetic lines of the magnetic component  20  cross the induction coil  13  and are cut by it, but an induced voltage produced in the induction coil  13  is changed in its voltage direction. However, the different directions of induced voltages may charge and discharge an energy storage component (not shown) during a cycle of each blink. Therefore, a next embodiment (See  FIG. 5 ) will propose a circuit to resolve such a discharge problem. 
       FIG. 4A  and  FIG. 4B  illustrate the magnetic component having a motion relative to the induction coil in accordance with an embodiment of the present application. Compared with  FIGS. 3A and 3B , these diagrams can clearly illustrate that the magnetic component  20  has a motion relative to the induction coil  13  of the contact lens  10  when a person blinks his eye. The average of person&#39;s blink is about dozens of times per minute. An induced voltage or energy is accordingly produced during each blink so as to power the physiological signal sensing component  12 , the transceiver and processer circuit  14 , and other power consuming components. For example, a power management component, a control circuit, a microprocessor, a communication component, a power supply, a sensor, a actuator, an LED, photosensor and so on (not shown; i.e. not limit to the embodiment as shown in  FIG. 1 ) requires electrical power from the induced voltage or energy. 
       FIG. 5  is the function block diagram of a circuitry within a contact lens in accordance with an embodiment of the present invention. In view of above, induced voltages with different directions are produced in an induction coil (or antenna)  51  during a cycle of each blink. A power management circuit  52  can covert the induced voltages with different directions to a voltage with one direction through rectification, voltage limitation, and voltage stabilization. Thus, an energy storage component  53  can be effectively and fully charged. In this regard, there are no chances to discharge the energy storage component  53 . The energy storage component  53  is a capacitor, an inductor, or a battery (MEMS miniature battery), and powers a physiological signal sensing component  54  and a transceiver and processer circuit  55  through the power management circuit  52 . The transceiver and processer circuit  55  can convert the electrical signals (e.g. voltage signals or current signals) generated from the physiological signal sensing component  54  to radio frequency (RF) signals, and wireless signals are transmitted outwards by the induction coil  51 . 
       FIG. 6  is a schematic diagram of a system of power transmission to a contact lens in accordance with another embodiment of the present invention. A system uses a mobile phone  61  or a notebook computer  62  as a receiving analyzer which at least comprises a signal receiving unit and an analyzing unit. The signal receiving unit receives wireless signals transmitted from the contact lens  10 . The analyzing unit may analyze and determine whether the intraocular pressure, humidity, temperature, pH, or the composition of tears is normal based on the wireless signals. The signal receiving unit may be a computer installed with specified software or an application program, a panel computer, a smart phone, a smart wrist watch or a portable device. 
       FIG. 7  is the function block diagram of a circuitry within a contact lens in accordance with another embodiment of the present invention. In view of above, when induced voltages with different directions are produced in an induction coil (or antenna)  71  during a cycle of each blink, a power management circuit  72  can convert them to a voltage with one direction through rectification, voltage limitation, and voltage stabilization. The power management circuit  72  comprises a rectifier (a full-wave rectifier or a bridge rectifier)  721  converting an induced voltage with varied polarities to one of constant polarity at its output, a voltage limiter  722  restraining the variation of the voltage, and a voltage stabilizer (a voltage regulator)  723 . Thus, an energy storage component  73  can store the energy and avoid being discharged. Moreover, a signal reading circuit  751  captures physical signals (electrical signals) generated from the physiological signal sensing component  74 , and further converts them into voltage signals, current signals or digital signals. The processed signals are transmitted to a processor (a microprocessor, microcontroller, or digital processor)  752  for simply conducting signal process or conversion (e.g. ADC). There are many signal processing methods such as correction, compression, decompression, encryption, and decryption, and they also may be applied to the signals for further processing. 
     A demodulator  753  receives the wireless signals collected by the induction coil  71  from the exterior of the contact lens, and recovers the high frequency wireless signals to low frequency signals. The wireless signals may be the control signals or other signals emitted from the mobile phone  61  or the notebook computer  62  ( FIG. 6 ). A modulator  754  comprises an envelope detector  7531  and a comparator  7532 . The modulator  754  can control or change the impedance (e.g. high impedance, medium impedance, low impedance) of the induction coil  71  to switch the induction coil  71  to generate an induced voltage or receive high frequency wireless signals from an exterior. The modulator  754  can convert the processed signals (low frequency) output from a processor  752  into high frequency wireless signals, and change the impedance of the induction coil  71  for feeding the induction coil high the frequency wireless signal to outwardly transmit them to communicate with an external receiver (the mobile phone  61  or the notebook computer  62 ). The processor  752  can control the operations of the signal reading circuit  751  and the modulator  754 . When a transceiver and processer circuit  75  is booted, a power-on reset circuit  755  rests its interior. An oscillator  756  generates a reference clock for the processor  752  to process signals. The power-on reset circuit  755  and the oscillator  756  can be integrated into the processor  752 . The modulator  754  can change the impedance of the induction coil  71 , and convert low frequency signals to radio frequency (RF) signals for the induction coil  71  to transmit wireless signal outwardly by changing the impedance of the induction coil  71 . The transceiver and processer circuit  75  includes the signal reading circuit  751 , the processor  752 , the demodulator  753 , the modulator  754 , the power-on reset circuit  755  and the oscillator  756 . Furthermore, the power management circuit  72  and the transceiver and processer circuit  75  can be integrated into a signal and power control circuit (or chip)  70 . The foregoing circuits are some examples, and may be replaced by various or similar equivalent circuits for each component or partial circuits but the application is not limit to the examples. 
     The foregoing embodiments of the invention have been presented for the purpose of illustration. Although the invention has been described by certain preceding examples, it is not to be construed as being limited by them. They are not intended to be exhaustive, or to limit the scope of the invention. Modifications, improvements and variations within the scope of the invention are possible in light of this disclosure.