Determining proximity of transmitter antennas of portable devices to a human body for limiting transmitter output power to meet specific absorption rate (SAR) requirements

• US 10,425,171 B2
• Filed: 12/15/2017
• Issued: 09/24/2019
• Est. Priority Date: 12/16/2016
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Seyed, Shurhabeel Zamir, Shee, Koon Keong, Aly, Aly
• Primary Examiner(s): Le, Nhan T
• Application Number:
  US15/844,392
• Publication Number:
  US 20180175944A1
• Time in Patent Office: 648 Days
• CPC Class Codes: H04B 1/3833 Hand-held transceivers
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04B 17/102 Power radiated at antenna
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range

Abstract

A method for adjusting transmitter output power (P_TX) comprises sensing, by a proximity sensor communicatively coupled to a transmitting device, whether an object is proximate to the transmitting device. The method further comprises analyzing an image from a camera to determine whether the transmitting device is proximate to a portion of a human body, when the proximity sensor senses the object proximate to the transmitting device. Further, the method comprises adjusting the P_TX of an antenna operatively coupled to the transmitting device to be less than or equal to a SAR threshold output power (P_SARMAX), when it is determined that the transmitting device is proximate to the portion of the human body or when it cannot be determined whether the transmitting device is proximate to a portion of a human body.

Claims

1. A method, comprising:

sensing, by a proximity sensor communicatively coupled to a transmitting device, whether an object is proximate to the transmitting device;

determining whether the transmitting device or a portion thereof is proximate to a portion of a human body at least by;

determining whether the transmitting device or a portion thereof is within a field of view of an image sensing system that is communicably coupled to the transmitting device; and

analyzing data captured by the image sensing system to determine whether the transmitting device or the portion thereof is proximate to the portion of the human body based in part or in whole upon results of determining whether the transmitting device or the portion thereof is within the field of view of the image sensing system; and

adjusting transmitting output power of an antenna operatively coupled to the transmitting device to be less than or equal to a threshold output power based in part or in whole upon results of determining whether the transmitting device or the portion thereof is proximate to the portion of the human body.

2. A method, comprising:

sensing, by a proximity sensor communicatively coupled to a transmitting device, an object proximate to the transmitting device;

determining whether transmitter output power of an antenna operatively coupled to the transmitting device is greater than a threshold output power;

obtaining image data from an image sensing system that is communicably coupled to the transmitting device;

determining whether the transmitting device is proximate to a portion of a human body at least by;

determining whether the transmitting device or a portion thereof is within a field of view of the image sensing system; and

analyzing data captured by the image sensing system to determine whether the transmitting device or the portion thereof is proximate to the portion of the human body based in part or in whole upon results of determining whether the transmitting device or the portion thereof is within the field of view of the image sensing system; and

adjusting the transmitter output power to be less than or equal to the threshold output power based at least in part upon results of determining whether the transmitting device is proximate to the portion of the human body.

3. The method of claim 2, further comprising determining whether the antenna is configured to transmit the transmitter output power.

4. The method of claim 2, further comprising not adjusting the transmitter output power of the antenna, when the proximity sensor does not sense the object proximate to the transmitting device.

5. The method of claim 2, further comprising determining whether a human body proximity flag has been set, when it is determined that the transmitter output power of the antenna is not greater than the threshold output power.

6. The method of claim 5, further comprising delaying performance of the method by a predetermined amount of time, when it is determined that the human body proximity flag has been set.

7. The method of claim 5, further comprising not adjusting the transmitter output power of the antenna, when it is determined that the human body proximity flag has not been set.

8. The method of claim 2, further comprising clearing a human body proximity flag after of the image data has been obtained.

9. The method of claim 2, further comprising determining whether the transmitting device is proximate to the portion of the human body is confirmed.

10. The method of claim 9, further comprising setting a human body proximity flag, when it cannot be confirmed that that the transmitting device is not within the FOV of the camera.

11. The method of claim 2, further comprising not adjusting the transmitter output power of the antenna, when it is determined that the transmitting device is not proximate to the portion of the human body.

12. The method of claim 2, further comprising setting a human body proximity flag, when it is determined that the transmitting device is proximate to the portion of the human body or when it cannot be determined whether the transmitting device is proximate to the portion of the human body.

13. The method of claim 2, wherein the proximity sensor comprises an optical sensor, a capacitive touch sensor, or a mechanical button sensor.

14. The method of claim 2, wherein the antenna is internal or external to the transmitting device.

15. The method of claim 2, wherein the antenna is configured to transmit a radio frequency (RF) signal.

16. The method of claim 2, wherein the image sensing system is operatively coupled to a user device.

17. The method of claim 16, wherein the user device comprises a head-mounted display.

18. A system, comprising:

a transmitting device;

an antenna operatively coupled to the transmitting device;

a proximity sensor, communicatively coupled to the transmitting device, to sense an object proximate to the transmitting device;

an image sensing system communicably coupled to the transmitting device to capture image data; and

a processor configured at least to;

determine whether transmitter output power of the antenna is greater than a threshold output power,

determine whether the transmitting device is proximate to a portion of a human body at least by;

determining whether the transmitting device or a portion thereof is within a field of view of the image sensing system; and

analyzing data captured by the image sensing system to determine whether the transmitting device or the portion thereof is proximate to the portion of the human body based in part or in whole upon results of determining whether the transmitting device or the portion thereof is within the field of view of the image sensing system; and

adjust the transmitter output power to be less than or equal to the threshold output power based at least in part upon results of determining whether the transmitting device is proximate to the portion of the human body.

19. The system of claim 18, wherein the processor determines whether the antenna is configured to transmit the transmitter output power.

20. The system of claim 18, wherein the processor does not adjust the transmitter output power of the antenna when it is confirmed that the transmitting device is not proximate to the portion of the human body.

21. The system of claim 18, wherein the processor determines whether a human body proximity flag has been set when the processor determines that the transmitter output power of the antenna is not greater than the threshold output power.

22. The system of claim 21, wherein performance of the processor is delayed by a predetermined amount of time when the processor determines that the human body proximity flag has been set.

23. The system of claim 21, wherein the processor does not adjust the transmitter output power of the antenna when the processor determines that the human body proximity flag has not been set.

24. The system of claim 18, wherein the processor clears a human body proximity flag after the image data has been captured.

25. The system of claim 18, wherein the processor determines whether it can be confirmed that the transmitting device is proximate to the portion of the human body.

26. The system of claim 25, wherein the processor adjusts the transmitter output power of the antenna to be less than or equal to threshold output power when the processor determines that it cannot be confirmed that the transmitting device is not proximate to the portion of the human body.

27. The system of claim 18, wherein the processor does not adjust the transmitter output power of the antenna when the processor determines that the transmitting device is not proximate to the portion of the human body.

28. The system of claim 18, wherein the processor sets a human body proximity flag when the processor determines that the transmitting device is proximate to the portion of the human body, or when the processor cannot confirm whether the transmitting device is not proximate to the portion of the human body.

29. The system of claim 18, wherein the proximity sensor comprises an optical sensor, a capacitive touch sensor, or a mechanical button sensor.

30. The system of claim 18, wherein the antenna is internal or external to the transmitting device.

31. The system of claim 18, wherein the antenna is configured to transmit a radio frequency (RF) signal.

32. The system of claim 18, wherein the image sensing system is operatively coupled to a user device.

33. The system of claim 32, wherein the user device comprises a head-mounted display.