Optical telemetry of data and power for wireless biomedical sensors and actuators

• US 6,898,464 B2
• Filed: 10/03/2001
• Issued: 05/24/2005
• Est. Priority Date: 10/05/2000
• Status: Expired due to Fees

• Current Assignee: Innersea Technology
• Original Assignee: Innersea Technology
• Inventors: Sexton, Sean V., Larson, Bruce C., Edell, David J.
• Primary Examiner(s): Layno, Carl H.
• Application Number:
  US09/969,871
• Publication Number:
  US 20020107557A1
• Time in Patent Office: 1,329 Days
• Field of Search: 607/2, 607/32, 607/60, 128/903, 128/904, 600/544
• US Class Current: 607/60
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0017 transmitting optical signals transmission by light H04B10/00
• CPC Class Codes: A61B 5/0028 Body tissue as transmission medium, i.e. transmission systems where the medium is the human body
• CPC Class Codes: H04B 10/807 Optical power feeding, i.e. transmitting power using an optical signal
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

An apparatus and corresponding method for providing data communications to and from a location within a body cavity in which an internal transmitter receives a first data stream from an in vivo sensor, electrode, or transducer. The internal transmitter is configured and arranged to asynchronously modulate the first data stream and to provide as an output a first optical signal carrying the asynchronously modulated first data stream. The apparatus further includes an external receiver that is configured and arranged external to the body cavity such that an optical input to the external receiver is optically coupled to the internal transmitter output and receives the optical signal therefrom. The external receiver asynchronously demodulates the received optical signal and provides as an output at least one signal indicative of the first data stream.

Claims

1. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

an internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream; and

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream.

2. The apparatus of claim 1

wherein the internal transmitter includes:

an encoder module coupled to a first electronic module and receiving the data stream therefrom, the encoder configured and arranged to asynchronously modulate the first data stream using said asynchronous modulation scheme and to provide as an output an optical drive signal modulated with the encoded first data stream; and

an optical transmitter coupled to the encoder module and receiving the optical drive signal therefrom, the optical transmitter configured and arranged to provide the optical signal according to the optical drive signal; and

wherein the external receiver includes;

an optical receiver optically coupled to the output optical signal of the internal transmitter, the optical receiver configured and arranged to convert the received optical signal into a first electronic signal; and

a demodulator coupled to the optical receiver and receiving the first electronic signal therefrom, the demodulator configured and arranged to asynchronously demodulate the first electronic signal and to provide at least one output signal representative of the first data stream.

6. The apparatus of claim 1 wherein the asynchronous modulation scheme is a frequency modulation scheme.

3. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream; and

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream,

wherein the asynchronous modulation scheme is a pulse position modulation scheme.

4. The apparatus of claim 3 wherein the pulse position modulation scheme is a pulse period modulation scheme.

5. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream; and

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream,

wherein the asynchronous modulation scheme is an amplitude modulation scheme.

7. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream;

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream;

wherein the internal transmitter includes an encoder module coupled to a first electronic module and receiving the data stream therefrom, the encoder configured and arranged to asynchronously modulate the first data stream using said asynchronous modulation scheme and to provide as an output an optical drive signal modulated with the encoded first data stream, and an optical transmitter coupled to the encoder module and receiving the optical drive signal therefrom, the optical transmitter configured and arranged to provide the optical signal according to the optical drive signal;

wherein the external receiver includes an optical receiver optically coupled to the output optical signal of the internal transmitter, the optical receiver configured and arranged to convert the received optical signal into a first electronic signal, and a demodulator coupled to the optical receiver and receiving the first electronic signal therefrom, the demodulator configured and arranged to asynchronously demodulate the first electronic signal and to provide at least one output signal representative of the first data stream; and

further including;

an internal input multiplexer having a plurality of inputs each coupled to one of a first plurality of data streams, the input multiplexer further including an output coupled to the encoder, the input multiplexer configured and arranged to multiplex the plurality of data streams into an output signal of a first multiplexed data stream, the output of the input multiplexer coupled to the encoder for encoding thereby and wherein the first optical signal is modulated with the encoded first multiplexed data stream,

wherein the first optical signal is transmitted and received by the optical receiver, the demodulator providing as an output a second multiplexed data stream and further including an output multiplexer having an input coupled to the demodulator and receiving the second multiplexed data stream, the output multiplexer having a plurality of outputs, the output multiplexer configured and arranged to de-multiplex the plurality of data streams into a plurality of output signals, wherein each of the plurality of output signals corresponds to at least one of the plurality of data streams.

8. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream;

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream;

an external transmitter disposed external to the body cavity, the external transmitter receiving a second data stream, the external transmitter configured and arranged to modulate the second data stream using a modulation scheme and to provide as an output a second optical signal carrying the modulated second data stream; and

an internal receiver configured and arranged internal to the body cavity such that an input to the internal receiver is optically coupled to the external transmitter output and receives the second optical signal therefrom, the internal receiver further configured and arranged to demodulate the second optical signal and to provide as an output at least one signal representative of the second data stream, wherein bi-directional communications are obtained to and from the body cavity.

9. The apparatus of claim 8 wherein the modulation scheme is a asynchronous modulation scheme.

10. The apparatus of claim 9 wherein the modulation scheme is a pulse modulation scheme.

11. The apparatus of claim 8 wherein the modulation scheme is an asynchronous modulation scheme.

12. The apparatus of claim 11 wherein the modulation schema is a pulse position modulation scheme.

13. The apparatus of claim 12 wherein the pulse position modulation scheme is a pulse period modulation scheme.

14. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream;

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream;

an external transmitter disposed external to the body cavity, the external transmitter receiving a second data stream, the external transmitter configured and arranged to modulate the second data stream using a modulation scheme and to provide as an output a second optical signal carrying the modulated second data stream; and

an internal receiver configured and arranged internal to the body cavity such that an input to the internal receiver is optically coupled to the external transmitter output and receives the second optical signal therefrom, the internal receiver further configured and arranged to demodulate the second optical signal and to provide as an output at least one signal representative of the second data stream, wherein bi-directional communications are obtained to and from the body cavity,

wherein a second electronic module includes a plurality of outputs and provides a second plurality of data streams therefrom, and further includes an external input multiplexer having a plurality of inputs each coupled to a corresponding one of the plurality of outputs of the second electronic module, the external input multiplexer further including an output coupled to the external encoder, the input multiplexer configured and arranged to multiplex the second plurality of data streams into an external output signal of a third multiplexed data stream, the output of the external input multiplexer coupled to the external encoder for encoding thereby and wherein the second optical signal is modulated with the encoded second multiplexed data stream, and

wherein the second optical signal is transmitted and received by the internal optical receiver, the internal demodulator providing as an output a fourth multiplexed data stream and further including an internal output multiplexer having an input coupled to the internal demodulator and receiving the second multiplexed data stream therefrom, the internal output multiplexer having plurality of outputs, the internal output multiplexer configured and arranged to de-multiplex the fourth multiplexed data stream into a second plurality of output signals, wherein each of the second plurality of output signals corresponds to at least one of the second plurality of data streams.

15. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream;

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream; and

a light pipe optically coupled to the optical transmitter and configured and arranged to transfer the first optical signal from the internal transmitter to a first transmit location.

16. The apparatus of claim 15 wherein the light pipe is a silicone light pipe.

17. The apparatus of claim 16 wherein the silicone light pipe is an optical fiber.

18. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream using an asynchronous modulation scheme and to provide as output a first optical signal carrying the asynchronously modulated first data stream; and

an external receiver configured and arranged external to the body cavity, the external receiver having an optical input optically coupled to the internal transmitter output, wherein the optical input of the external receiver receives the optical signal from the internal transmitter, the external receiver further configured and arranged to asynchronously demodulate the optical signal and to provide as an output at least one signal indicative of the first data stream,

wherein the internal transmitter includes at least one circuit using MOSFET transistors operating in the subthreshold region of operation.

19. An apparatus for providing data communications to and from a location within a body cavity, the apparatus comprising:

a internal transmitter receiving a first data stream, the internal transmitter configured and arranged to asynchronously modulate the first data stream and to provide as output a first optical signal carrying the asynchronously modulated first data stream; and

at least one overcoat layer encapsulating the internal transmitter, at least one overcoat layer providing the encapsulated internal transmitter with a density substantially matching the density of the body cavity.

20. The apparatus of claim 19 wherein at least one overcoat layer includes a low density foam material and wherein the density of the low density foam material is adjusted to substantially match the body cavity surrounding the internal transmitter using hollow glass micro-spheres.

21. The apparatus of claim 20 wherein the low density foam material is a low density silicone foam.

22. An offset cancellation stage for reducing low frequency and DC offset voltages in an electronic device including an input amplifier having a first input implanted within a body cavity, providing a first data stream as telemetry from a location within a body cavity, the first data stream provided by a first electronic module, the offset cancellation stage comprising:

a feedback circuit having the first input of the input amplifier coupled to one input of a first difference module, the output of the difference module provided to the input amplifier having a first transfer function, the input amplifier providing as an output signal, a second difference module having as a first input the output signal and as a second input a reference signal coupled thereto, the second difference module providing the difference between the output signal and the reference signal as an input to a feedback module having a second transfer function, the feedback module providing a feedback signal to the second input of the first difference module wherein the output of the first difference module is the difference between the first data stream and the feedback signal, wherein the second transfer function is selected to remove low frequency and DC offset components from the first data stream.

23. A method for providing data communications to and from a location within a body cavity, the method comprising the steps of:

providing at least one internal electrical signal;

encoding at least one internal electrical signal;

modulating an internal optical transmitter to provide an optical signal in an asynchronous modulation scheme according to the encoded at least one internal electrical signal;

transmitting the modulated optical signal through the body cavity;

receiving the modulated optical signal externally to the body cavity by an external optical receiver;

demodulating the received optical signal to provide an external demodulated electrical signal; and

decoding the external demodulated electrical signal to provide an external electrical signal representative of the internal electrical signal.

24. The method of claim 23, the method further comprising the steps of:

providing at least one external electrical signal;

encoding at least one external electrical signal;

modulating an external optical transmitter to provide an optical signal in a modulation scheme according to the encoded at least one external electrical signal;

transmitting the modulated optical signal into the body cavity;

receiving the modulated optical signal internally within the body cavity by an internal optical receiver;

demodulating the received optical signal to provide an internal demodulated electrical signal; and

decoding the external demodulated electrical signal to provide an internal electrical signal representative of the external electrical signal.

25. The method of claim 23 further wherein the step of transmitting the modulated optical signal through the body cavity includes the steps of:

transmitting the modulated optical signal;

receiving the modulated optical signal at an input of a light transmissive light pipe;

transmitting the modulated optical signal through the light pipe to a first transmitting location; and

transmitting from an output of the light pipe the modulated optical signal through the body cavity from the first transmitting location.