Dynamically reconfigurable apertures for optimization of PPG signal and ambient light mitigation

• US 10,117,587 B2
• Filed: 04/26/2016
• Issued: 11/06/2018
• Est. Priority Date: 04/27/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Han, Chin San
• Primary Examiner(s): Wu, Eugene T
• Application Number:
  US15/139,133
• Publication Number:
  US 20160310027A1
• Time in Patent Office: 924 Days
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6898 Portable consumer electronic devices, e.g. music players, telephones, tablet computers
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths

Abstract

This relates to an electronic device with dynamically reconfigurable apertures to account for different skin types, usage conditions, and environmental conditions and methods for measuring the user'"'"'s physiological signals. The device can include one or more light emitters, one or more light sensors, and a material whose optical properties can be changed in one or more locations to adjust the optical path and the effective separation distances between the one or more light emitters and one or more light sensors or the size, location, or shape of the one or more dynamically reconfigurable apertures. In some examples, the material can be a liquid crystal material, MEMS shutter layer, or light guide, which can form the one or more dynamically reconfigurable apertures. In some examples, the light emitters or light sensors or both can be an array of individually addressable optical components.

Claims

1. An electronic device for measuring physiological information, the device comprising:

one or more light emitters configured to emit light;

one or more light sensors configured to detect a reflection of the emitted light and generate one or more signals indicative of the detected reflected light;

a device component capable of forming dynamically reconfigurable apertures having a configuration to allow light to be transmitted from at least one of the one or more light emitters to at least one of the one or more light sensors, each aperture including a center location; and

a processor configured to;

dynamically adjust a separation distance between the center locations of at least two of the apertures; and

determine the physiological information based on the one or more signals.

2. The electronic device of claim 1, wherein the electronic device is capable of dynamically reconfiguring one or more of a size of the apertures, a location of the apertures, and a shape of the apertures.

3. The electronic device of claim 1, wherein the one or more light sensors includes at least two light sensors capable of sensing different wavelengths.

4. The electronic device of claim 1, wherein the one or more light emitters includes at least two light emitters capable of emitting at different wavelengths.

5. The electronic device of claim 3 or claim 4, wherein:

wherein a sensing wavelength of at least one of the one or more light sensors or an emission wavelength of at least one of the one or more light emitters and separation distance associated with a second configuration is longer than a sensing wavelength of the at least one of the one or more light sensors or an emission wavelength of the at least one of the one or more light emitters and separation distance, respectively, associated with a first configuration.

6. The electronic device of claim 1, wherein the processor is further configured to:

change one or more optical properties of the device component to form the apertures.

7. The electronic device of claim 6, wherein the device component comprises a liquid crystal layer capable of forming the apertures.

8. The electronic device of claim 6, wherein the device component comprises a plurality of microelectromechanical (MEMS) shutters capable of forming the apertures.

9. The electronic device of claim 6, wherein the one or more optical properties of the device component are different in a location corresponding to the center locations than a location outside of the apertures.

10. The electronic device of claim 1, wherein the one or more light emitters are formed from an array of individually addressable light emitters.

11. The electronic device of claim 1, wherein the one or more light sensors are formed from an array of individually addressable light sensors.

12. The electronic device of claim 1, further comprising at least one optical filter, wherein at least one of the one or more light emitters is a broadband source coupled to the at least one optical filter.

13. The electronic device of claim 1, wherein the device component comprises a light guide configured to receive at least one of the emitted light and the reflected light.

14. The electronic device of claim 13, wherein at least one of the emitted light and the reflected light enters or exits the light guide in a location different from a location corresponding to the one or more light emitters or the one or more light sensors.

15. The electronic device of claim 13, wherein the light guide is located on a same layer as at least one of the one or more light emitters and the one or more light sensors.

16. The electronic device of claim 1, wherein the one or more light emitters are located on a different layer than the one or more light sensors.

17. An electronic device for measuring physiological information, the device comprising:

one or more light emitters configured to emit light;

one or more light sensors configured to detect a reflection of the emitted light and generate one or more signals indicative of the detected reflected light; and

a device component capable of forming dynamically reconfigurable apertures having a configuration to allow light to be transmitted from at least one of the one or more light emitters to at least one of the one or more light sensors,

a processor configured to;

determine the physiological information based on the one or more signals;

wherein;

during a first configuration;

the one or more light emitters are configured to emit a first light,

the one or more light sensors are configured to receive a second light, the second light being a reflection of the first light, and

the apertures, each having a center location, are configured to;

allow the first light to be transmitted from the one or more light emitters, and

allow the second light to be received at the one or more light sensors; and

during a second configuration;

the one or more light emitters are configured to emit a third light,

the one or more light sensors are configured to receive a fourth light, the fourth light being a reflection of the third light,

the apertures are configured to;

allow the third light to be transmitted from the one or more light emitters, and

allow the fourth light to be received at the one or more light sensors; and

wherein the processor is further configured to compare a signal from the second light to a signal from the fourth light and dynamically adjust a separation distance between the center locations of the apertures from the first configuration to the second configuration.

18. The electronic device of claim 17, wherein the processor is further configured to:

determine a PPG signal from the first configuration; and

determine a perfusion index from the second configuration.

19. The electronic device of claim 17, wherein the processor is further configured to:

dynamic reconfigure the apertures one or more of a different size of the apertures, a different location of the apertures, and a different shape of the apertures.

20. The electronic device of claim 17,

wherein the apertures of the second configuration block light at a location of the first light emitted by the one or more light emitters during the first configuration, and the apertures of the first configuration block light at a location of the third light emitted by the one or more light emitters during the second configuration.

21. The electronic device of claim 17, wherein the apertures are configured with a third configuration, the third configuration based on the compared signals and being one of the configurations used in the comparison.

22. The electronic device of claim 17, wherein the first configuration is associated with a first determination of aperture size, location, and shape, and the second configuration is associated with a second determination of aperture size, location, and shape,

wherein the first determination is coarser than the second determination.

23. The electronic device of claim 17, wherein the apertures are capable of being dynamically reconfigured from the first configuration to the second configuration during an initial calibration procedure.

24. The electronic device of claim 17, wherein the processor is further configured to:

control a voltage of a liquid crystal material to dynamically reconfigure the apertures.

25. The electronic device of claim 17, wherein the device component includes a plurality of individual sections, wherein the processor is further configured to control each individual section.

26. The electronic device of claim 25, further comprising:

a plurality of electrodes, wherein the processor is further configured to apply a voltage difference to control the plurality of individual sections to dynamically change one or more of a size, number, location, and shape of the apertures.

27. The electronic device of claim 17, further comprising:

a window located at or near an external housing of the electronic device,

wherein an active area of the one or more light emitters and an active area of the one or more light sensors face the external housing, and the device component is located proximate to the window.

28. The electronic device of claim 17, further comprising:

an optical component layer including the one or more light emitters and the one or more light sensors.

29. The electronic device of claim 17, wherein the one or more light emitters are located on a different layer than the one or more light sensors.