Electronic device and method of estimating skin surface temperature using the same

1 . An electronic device comprising:

a first temperature sensor configured to measure a first temperature at a first position when an object comes into contact with a contact surface of a main body of the electronic device;

a second temperature sensor spaced apart from the first temperature sensor, and configured to measure a second temperature at a second position;

a third temperature sensor disposed inside the main body, and configured to measure a third temperature at a third position when heat is generated inside the main body; and

a processor configured to:

detect a temperature change due to heat generation inside the main body based on:

T

1

,

t

⁢

2

-

T

1

,

t

⁢

1

t

2

-

t

1

⁢

and

⁢

T

2

,

t

⁢

2

-

T

2

,

t

⁢

1

t

2

-

t

1

wherein T 1,t1 and T 1,t2 denote the first temperatures measured at two different time points t 1 and t 2 , respectively, T 2,t1 and T 2,t2 denote the second temperatures measured at the two different time points t 1 and t 2 , respectively;

T

1

-

T

2

T

1

-

T

3

⁢

and

⁢

T

1

-

T

2

T

1

-

T

3

wherein T 1 , T 2 , and T 3 denote the first temperature, the second temperature, and the third temperature that are respectively measured at a same time point, which is either the time point t 1 or the time point t 2 ; and

estimate skin surface temperature based on the first temperature T 1 , the second temperature T 2 , the third temperature T 3 , and the temperature change,

wherein the first position is closer to the contact surface of the main body than the second position and the third position, and the third position is closer to a layer comprising or mounting the processor or a battery than the first position and the second position, and the second position is located between the first position and the third position in a thickness direction of the main body.

2 . The electronic device of claim 1 , wherein a first condition is satisfied when the change in the first temperature T 1 is greater than or equal to a predetermined first threshold value, and a second condition is satisfied when the change in the second temperature T 2 is greater than or equal to a predetermined second threshold value, and

wherein in response to either one or both of the first condition and the second condition is satisfied, the processor is further configured to determine that the temperature change has occurred due to the heat generation inside the main body.

3 . The electronic device of claim 2 , wherein in response to the temperature change being detected, the processor is further configured to determine the first temperature T 1 and the second temperature T 2 as outliers.

4 . The electronic device of claim 3 , wherein in response to the first temperature T 1 and the second temperature T 2 being determined as the outliers, the processor is further configured to terminate measurement of the first temperature T 1 and the second temperature T 2 , or guide re-measurement of the first temperature T 1 and the second temperature T 2 after a lapse of a predetermined period of time.

5 . The electronic device of claim 1 , wherein in response to

T

1

-

T

2

T

1

-

T

3

⁢

and

⁢

T

1

-

T

2

T

1

-

T

3

being greater than or equal to a predetermined third threshold value when the first temperature is higher than the third temperature T 3 , or in response to

T

1

-

T

2

T

1

-

T

3

⁢

and

⁢

T

1

-

T

2

T

1

-

T

3

being less than or equal to a predetermined fourth threshold value when the third temperature T 3 is higher than the first temperature T 1 , the processor is further configured to determine that the temperature change has occurred due to the heat generation inside the main body.

6 . The electronic device of claim 5 , wherein upon determining that the temperature change has occurred, the processor is further configured to correct the first temperature T 1 and the second temperature T 2 based on the third temperature T 3 .

7 . The electronic device of claim 6 , wherein the processor is further configured to correct each of the first temperature T 1 and the second temperature T 2 by subtracting from each of the first temperature T 1 and the second temperature T 2 in the main body, heat that is transferred from a heat generating component to the first temperature sensor and the second temperature sensor, respectively.

8 . The electronic device of claim 7 , wherein the processor is further configured to estimate the skin surface temperature based on a difference between the corrected first temperature T 1 and the corrected second temperature T 2 .

9 . The electronic device of claim 1 , wherein the third temperature sensor is attached to a heat generating component that generates heat at a predetermined temperature inside the main body.

10 . The electronic device of claim 1 , wherein when the main body of the electronic device is in contact with a skin surface of the object, the first temperature sensor is disposed at a distance of 5 mm or less from the skin surface.

11 . A wearable device comprising:

a main body comprising:

a first temperature sensor disposed in the main body at a first position spaced apart from a contact surface of the wearable device by a first distance, and configured to measure a first temperature at the first position;

a second temperature sensor disposed in the main body at a second position spaced apart from the contact surface of the wearable device by a second distance, which is greater than the first distance, and configured to measure a second temperature at the second position;

a third temperature sensor disposed in the main body at a third position spaced apart from the contact surface by a third distance, which is greater than the second distance, and configured to measure a third temperature at the third position; and

a processor configured to:

detect a temperature change due to heat generation inside the main body based on:

T

1

,

t

⁢

2

-

T

1

,

t

⁢

1

t

2

-

t

1

⁢

and

⁢

T

2

,

t

⁢

2

-

T

2

,

t

⁢

1

t

2

-

t

1

wherein T 1,t1 and T 1,t2 denote the first temperatures measured at two different time points t 1 and t 2 , respectively, T 2,t1 and T 2,t2 denote the second temperatures measured at the two different time points t 1 and t 2 , respectively;

T

1

-

T

2

T

1

-

T

3

⁢

and

⁢

T

1

-

T

2

T

1

-

T

3

wherein T 1 , T 2 , and T 3 denote the first temperature, the second temperature, and the third temperature that are respectively measured at a same time point, which is either the time point t 1 or the time point t 2 ; and

estimate skin surface temperature based on the first temperature T 1 , the second temperature T 2 , the third temperature T 3 , and the temperature.

12 . The wearable device of claim 11 , wherein the processor is further configured to correct the first temperature T 1 and the second temperature T 2 based on the third temperature T 3 measured by the third temperature sensor when heat is generated inside the main body, and estimate the skin surface temperature based on the corrected first temperature T 1 and the corrected second temperature T 2 .

13 . The wearable device of claim 11 , wherein the third distance is 65 mm or less.

14 . The wearable device of claim 11 , wherein the main body further comprises a photoplethysmogram (PPG) sensor configured to measure a bio-signal of a user when the wearable device is worn by the user, and the processor is further configured to estimate blood pressure based on the bio-signal and the skin surface temperature.

15 . The wearable device of claim 11 , wherein the first distance is 5 mm or less, and the second distance is 15 mm or less.