METHOD FOR INDUCING SLEEP WITH SOUNDS AND SOUND PLAYBACK DEVICE PERFORMING THE SAME

1 . A method for inducing sleep with sounds, applied to a sound playback device, the sound playback device configured to play an inducing sound having a frequency difference to a user, the method comprising the steps of:

calculating and obtaining N sleep cycles based on an estimated sleep time of the user, where 3≤N≤15; and

playing the inducing sound within at least three sleep cycles, the inducing sound comprising a first stage, a second stage, a third stage and a fourth stage;

wherein, in the first stage, the frequency difference of the inducing sound decreases in a continuous moderate decremental manner from a first frequency difference to a second frequency difference, wherein the continuous moderate decremental manner is to decrease the frequency difference at an interval of no more than X seconds, where 0<X≤10, or to reduce the frequency difference by no more than Y hertz each time, where 0<Y≤1;

in the second stage, the frequency difference of the inducing sound is kept at the second frequency difference;

in the third stage, the frequency difference of the inducing sound increases in a continuous moderate incremental manner from the second frequency difference to a third frequency difference, wherein the continuous moderate incremental manner is to increase the frequency difference at an interval of no more than Z seconds, where 0<Z≤10, or to increase the frequency difference by no more than S hertz each time, where 0<S≤1; and

in the fourth stage, the frequency difference of the inducing sound is kept at the third frequency difference.

2 . The method as claimed in claim 1 , wherein the first frequency difference is a hertz, the second frequency difference is b hertz, and the third frequency difference is c hertz, where 10≤a≤20, 2≤b≤4, and 10≤c≤20.

3 . The method as claimed in claim 1 , wherein the estimated sleep time is calculated and obtained according to a predicted sleep time and a predicted wake-up time.

4 . The method as claimed in claim 3 , wherein the predicted wake-up time is determined according to an alarm reminder time set by the user.

5 . The method as claimed in claim 3 , wherein the predicted sleep time is determined according to a body tossing state of the user, and the predicted wake-up time is determined by an alarm reminder time set by the user.

6 . A sound playback device, configured to play an inducing sound having a frequency difference to a user, the sound playback device comprising:

a speaker; and

a sound playback controller, electrically connected to the speaker, the sound playback controller calculating and obtaining N sleep cycles based on an estimated sleep time of the user, where 3≤N≤15, and controlling the speaker to play the inducing sound within at least three sleep cycles, the inducing sound comprising a first stage, a second stage, a third stage and a fourth stage;

wherein, in the first stage, the frequency difference of the inducing sound decreases in a continuous moderate decremental manner from a first frequency difference to a second frequency difference, wherein the continuous moderate decremental manner is to decrease the frequency difference at an interval of no more than X seconds, where 0<X≤10, or to reduce the frequency difference by no more than Y hertz each time, where 0<Y≤1;

in the second stage, the frequency difference of the inducing sound is kept at the second frequency difference;

in the third stage, the frequency difference of the inducing sound increases in a continuous moderate incremental manner from the second frequency difference to a third frequency difference, wherein the continuous moderate incremental manner is to increase the frequency difference at an interval of no more than Z seconds, where 0<Z≤10, or to increase the frequency difference by no more than S hertz each time, where 0<S≤1; and

in the fourth stage, the frequency difference of the inducing sound is kept at the third frequency difference.

7 . The sound playback device as claimed in claim 6 , wherein the first frequency difference is a hertz, the second frequency difference is b hertz, and the third frequency difference is c hertz, where 10≤a≤20, 2≤b≤4, and 10≤c≤20.

8 . The sound playback device according to claim 6 , wherein the estimated sleep time is calculated and obtained according to a predicted sleep time and a predicted wake-up time.

9 . The sound playback device as claimed in claim 8 , wherein the predicted wake-up time is determined according to an alarm reminder time set by the user.

10 . The sound playback device as claimed in claim 8 , wherein the predicted sleep time is determined according to a body tossing state of the user, and the predicted wake-up time is determined by an alarm reminder time set by the user.