Contact lens data transceiver
Embodiments of the disclosure relate to a low-power, high-data-rate, radio transceiver inside a contact lens. The radio transceiver includes a phase-locked loop having a frequency acquisition loop that turns on and off based on various performance characteristics of the transceiver. The transceiver also includes wireless power harvesting circuitry that receives a wireless power signal and generates a reference signal that is used by an oscillator within the transceiver.
1. A contact lens comprising:
an ultra-high-frequency (UHF) radio antenna contained within the contact lens;
a UHF radio transceiver contained within the contact lens and connected to the UHF radio antenna via a transmit/receive switch, the UHF radio transceiver designed to operate at a bit rate of one megabit per second or more; and
wherein the UHF radio transceiver comprises:
an analog UHF carrier phase tracking loop and an analog UHF frequency acquisition loop that share a voltage-controlled oscillator, the frequency acquisition loop designed to be turned off periodically during normal transceiver operation; and
an analog clock and data recovery module that is clocked no faster than the bit rate.
2. The contact lens of claim 1 further comprising:
digital processing circuits that operate on data received by the UHF radio transceiver where no such circuits that operate on received data within the contact lens are clocked faster than the bit rate.
3. The contact lens of claim 1 further comprising:
a high-frequency (HF) power coil that receives power via magnetic induction and an integrated circuit that conditions the received power to create a regulated direct-current electrical power supply for the UHF radio transceiver.
4. The contact lens of claim 3 wherein the UHF radio transceiver uses a reference frequency source that is based on a frequency of a wireless signal received by the HF power coil.
5. The contact lens of claim 4 wherein the HF power coil receives power from the wireless signal that is generated by an accessory device.
6. The contact lens of claim 1 further comprising:
a femtoprojector and an integrated circuit that receives video image data from the UHF radio transceiver and converts the data in to electronic signals to drive a light-emitting-diode microdisplay within the femtoprojector.
7. The contact lens of claim 1 further comprising:
an adjustable focus optical element and an integrated circuit that receives focus data from the UHF radio transceiver and converts the data into electronic signals to drive the optical element to change its focus.
8. The contact lens of claim 1 further comprising:
an electrochemical sensor and an integrated circuit that receives electronic signals from the electrochemical sensor and converts them into data that is transmitted by the UHF radio transceiver.
9. The contact lens of claim 1 further comprising:
motion sensors that output motion data that are transmitted by the UHF radio transceiver.
10. The contact lens of claim 1 wherein the UHF radio transceiver consumes less than 200 microwatts of power when transmitting and receiving data at a bit rate greater than one Megabit per second.
11. The contact lens of claim 1 wherein the UHF radio antenna is a dipole antenna.
12. The contact lens of claim 1 wherein the frequency acquisition loop is turned off unless a frame error rate of received data exceeds a threshold level.
13. The contact lens of claim 1 wherein the frequency acquisition loop is turned off unless a frame error rate of received data exceeds a threshold level.
14. A method for operating a contact lens, the method comprising:
operating an ultra-high-frequency (UHF) transceiver that comprises a phase tracking loop and a frequency tracking loop, the UHF transceiver operates at a bit rate of one Megabit per second or more, the UHF transceiver being coupled to an analog clock and data recovery module;
using the phase tracking loop to synchronize a carrier phase in the analog domain;
turning off the frequency tracking loop during normal transceiver operation; and
operating the analog clock and data recovery module at a clock rate that is no faster than the bit rate.
15. The method of claim 14 further comprising operating a digital processing circuit that is coupled to the UHF transceiver no faster than the bit rate.
16. The method of claim 14 further comprising using an integrated circuit to convert power that has been received by a high-frequency (HF) power coil via magnetic induction into a regulated direct-current to energize the UHF radio transceiver.
17. The method of claim 14 wherein the HF power coil receives power from a wireless signal that is generated by an accessory device.
18. The method of claim 14 further comprising using a femtoprojector to receive video image data from the UHF radio transceiver and convert the data in to electronic signals to drive a light-emitting-diode microdisplay within the femtoprojector.
19. The method of claim 14 further comprising using an adjustable focus optical element to receive focus data from the UHF radio transceiver and convert the data into electronic signals to drive the optical element to change its focus.
20. The method of claim 14 wherein the UHF radio transceiver consumes less than 200 microwatts of power when transmitting and receiving data at a bit rate greater than one Megabit per second.