DYNAMICALLY RECONFIGURABLE APERTURES FOR OPTIMIZATION OF PPG SIGNAL AND AMBIENT LIGHT MITIGATION

• US 20160310027A1
• Filed: 04/26/2016
• Published: 10/27/2016
• Est. Priority Date: 04/27/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: HAN, Chin San
• Granted Patent: US 10,117,587 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 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

a material capable of forming one or more dynamically reconfigurable apertures 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.

2. The electronic device of claim 1, further comprising

one or more light paths, each light path associated with one of the one or more light emitters and one of the one or more light sensors,

wherein the electronic device is capable of dynamically reconfiguring one or more of a separation distance of the one or more light paths, a size of the one or more dynamically reconfigurable apertures, a location of the one or more dynamically reconfigurable apertures, and a shape of the one or more dynamically reconfigurable apertures.

3. The electronic device of claim 1, wherein one or more optical properties of the material is changed to form the one or more dynamically reconfigurable apertures.

4. The electronic device of claim 3, wherein the material comprises a liquid crystal layer capable of forming the one or more dynamically reconfigurable apertures.

5. The electronic device of claim 3, wherein the material comprises a plurality of microelectromechanical (MEMS) shutters capable of forming the one or more dynamically reconfigurable apertures.

6. The electronic device of claim 1, wherein the material comprises a light guide configured to receive at least one of the emitted light and the reflection of the emitted light.

7. The electronic device of claim 6, wherein at least one of the emitted light and the reflection of the emitted light enters or exits the light guide in a location different from the one or more light emitters or the one or more light sensors.

8. The electronic device of claim 6, 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.

9. The electronic device of claim 3, wherein the optical properties of the material are different in a location corresponding to the one or more dynamically reconfigurable apertures than a location outside of the one or more dynamically reconfigurable apertures.

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

11. 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.

12. The electronic device of claim 10 or claim 11, further comprising

a first light path associated with at least one of the one or more light sensors and at least one of the one or more light emitters and having a first separation distance;

and

a second light path associated with at least one of the one or more light sensors and at least one of the one or more light emitters and having a second separation distance greater than the first separation distance,

wherein 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 associated with the second light path 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 associated with the first light path.

13. 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.

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

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

16. 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.

17. A method of determining a user'"'"'s physiological state with an electronic device, including one or more light emitters and one or more light sensors, the method comprising:

emitting a first light from the one or more light emitters;

receiving a second light by the one or more light sensors, the second light being a reflection of the first light; and

dynamically reconfiguring one or more apertures to a first configuration to allow the first light to be transmitted from the one or more light emitters, and to allow the second light to be received at the one or more light sensors.

18. The method of claim 17, further comprising associating a light path with one of the one or more light emitters and one of the one or more light sensors, wherein the dynamic reconfiguration of the one or more apertures leads to at least one of a different separation distance between the one or more light emitters and the one or more light sensors, a different size of the one or more apertures, a different location of the one or more apertures, and a different shape of the one or more apertures.

19. The method of claim 17, further comprising:

emitting a third light from the one or more light emitters;

receiving a fourth light by the one or more light sensors, the fourth light being a reflection of the third light; and

dynamically reconfiguring one or more apertures to a second configuration to allow the third light to be transmitted from the one or more light emitters, and to allow the fourth light to be received at the one or more light sensors,

wherein a separation distance for the first configuration is different from a separation distance different for the second configuration.

20. The method of claim 19 further comprising:

determining a PPG signal from the first configuration; and

determining a perfusion index from the second configuration.

21. The method of claim 19, wherein the one or more apertures of the second configuration block the second light and wherein the one or more apertures of the first configuration block the fourth light.

22. The method of claim 17, further comprising:

determining an amount of noise from a signal of the second light; and

dynamically reconfiguring the one or more apertures to a second configuration when the amount of noise or the signal of the second light is greater than or equal to a first threshold, the second configuration having a lower amount of noise than the first configuration.

23. The method of claim 17, further comprising:

determining a signal value of the second light; and

dynamically reconfiguring the one or more apertures to a second configuration when the signal value of the second light is less than or equal to a second threshold, the signal value of the second light being higher than a signal value of the first light in the first configuration.

24. The method of claim 17, further comprising controlling a voltage of a liquid crystal material to dynamically reconfigure the one or more apertures.

25. The method of claim 17, further comprising controlling a position of one or more microelectromechanical (MEMS) shutters to dynamically reconfigure the one or more apertures.

26. The method of claim 17, further comprising controlling an addressing of one or more individually addressable light emitters to dynamically change properties of one or more light paths, each light path associated with one of the one or more light emitters and one of the one or more light sensors.

27. The method of claim 17, further comprising controlling an addressing of one or more individually addressable light sensors to dynamically change properties of one or more light paths, each light path associated with one of the one or more light emitters and one of the one or more light sensors.

28. The method of claim 26 or 27, wherein the properties of the one or more light paths include at least one of a separation distance, a size, a location, and a shape.

29. The method of claim 17, wherein the dynamic reconfiguration is based on at least one of a user activity and an environmental condition.

30. The method of claim 17, further comprising:

emitting a third light from the one or more light emitters;

receiving a fourth light from the one or more light sensors, the fourth light being a reflection of the third light;

dynamically reconfiguring one or more apertures to a second configuration to allow the third light to be transmitted from the one or more light emitters, and to allow the fourth light to be received at the one or more light sensors;

emitting a fifth light from the one or more light emitters;

receiving a sixth light from the one or more light sensors, the sixth light being a reflection of the fifth light;

dynamically reconfiguring one or more apertures to a third configuration to allow the fifth light to be transmitted from the one or more light emitters, and to allow the sixth light to be received at the one or more light sensors; and

comparing a signal from the second light to a signal from the fourth and sixth light.

31. The method of claim 17, further comprising:

emitting a third light from the one or more light emitters;

receiving a fourth light from the one or more light sensors, the fourth light being a reflection of the third light;

dynamically reconfiguring one or more apertures to a second configuration in a first direction to allow the third light to be transmitted from the one or more light emitters, and to allow the fourth light to be received at the one or more light sensors;

comparing a signal from the second light to a signal from the fourth light; and

when a value associated with the signal from the second light is greater than or equal to a value associated with the fourth light,

emitting a fifth light from the one or more light emitters;

receiving a sixth light from the one or more light sensors, the sixth light being a reflection of the fifth light;

dynamically reconfiguring one or more apertures to a third configuration in a second direction, opposite the first direction, to allow the fifth light to be transmitted from the one or more light emitters, and to allow the sixth light to be received at the one or more light sensors.